/*
* Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
*
*
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*
*
*
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*/
package java.util;
import java.nio.file.
Path;
import java.nio.file.
Files;
import java.util.regex.*;
import java.io.*;
import java.math.*;
import java.nio.*;
import java.nio.channels.*;
import java.nio.charset.*;
import java.text.*;
import java.util.
Locale;
import sun.misc.
LRUCache;
/**
* A simple text scanner which can parse primitive types and strings using
* regular expressions.
*
* <p>A <code>Scanner</code> breaks its input into tokens using a
* delimiter pattern, which by default matches whitespace. The resulting
* tokens may then be converted into values of different types using the
* various <tt>next</tt> methods.
*
* <p>For example, this code allows a user to read a number from
* <tt>System.in</tt>:
* <blockquote><pre>{@code
* Scanner sc = new Scanner(System.in);
* int i = sc.nextInt();
* }</pre></blockquote>
*
* <p>As another example, this code allows <code>long</code> types to be
* assigned from entries in a file <code>myNumbers</code>:
* <blockquote><pre>{@code
* Scanner sc = new Scanner(new File("myNumbers"));
* while (sc.hasNextLong()) {
* long aLong = sc.nextLong();
* }
* }</pre></blockquote>
*
* <p>The scanner can also use delimiters other than whitespace. This
* example reads several items in from a string:
* <blockquote><pre>{@code
* String input = "1 fish 2 fish red fish blue fish";
* Scanner s = new Scanner(input).useDelimiter("\\s*fish\\s*");
* System.out.println(s.nextInt());
* System.out.println(s.nextInt());
* System.out.println(s.next());
* System.out.println(s.next());
* s.close();
* }</pre></blockquote>
* <p>
* prints the following output:
* <blockquote><pre>{@code
* 1
* 2
* red
* blue
* }</pre></blockquote>
*
* <p>The same output can be generated with this code, which uses a regular
* expression to parse all four tokens at once:
* <blockquote><pre>{@code
* String input = "1 fish 2 fish red fish blue fish";
* Scanner s = new Scanner(input);
* s.findInLine("(\\d+) fish (\\d+) fish (\\w+) fish (\\w+)");
* MatchResult result = s.match();
* for (int i=1; i<=result.groupCount(); i++)
* System.out.println(result.group(i));
* s.close();
* }</pre></blockquote>
*
* <p>The <a name="default-delimiter">default whitespace delimiter</a> used
* by a scanner is as recognized by {@link java.lang.Character}.{@link
* java.lang.Character#isWhitespace(char) isWhitespace}. The {@link #reset}
* method will reset the value of the scanner's delimiter to the default
* whitespace delimiter regardless of whether it was previously changed.
*
* <p>A scanning operation may block waiting for input.
*
* <p>The {@link #next} and {@link #hasNext} methods and their
* primitive-type companion methods (such as {@link #nextInt} and
* {@link #hasNextInt}) first skip any input that matches the delimiter
* pattern, and then attempt to return the next token. Both <tt>hasNext</tt>
* and <tt>next</tt> methods may block waiting for further input. Whether a
* <tt>hasNext</tt> method blocks has no connection to whether or not its
* associated <tt>next</tt> method will block.
*
* <p> The {@link #findInLine}, {@link #findWithinHorizon}, and {@link #skip}
* methods operate independently of the delimiter pattern. These methods will
* attempt to match the specified pattern with no regard to delimiters in the
* input and thus can be used in special circumstances where delimiters are
* not relevant. These methods may block waiting for more input.
*
* <p>When a scanner throws an {@link InputMismatchException}, the scanner
* will not pass the token that caused the exception, so that it may be
* retrieved or skipped via some other method.
*
* <p>Depending upon the type of delimiting pattern, empty tokens may be
* returned. For example, the pattern <tt>"\\s+"</tt> will return no empty
* tokens since it matches multiple instances of the delimiter. The delimiting
* pattern <tt>"\\s"</tt> could return empty tokens since it only passes one
* space at a time.
*
* <p> A scanner can read text from any object which implements the {@link
* java.lang.Readable} interface. If an invocation of the underlying
* readable's {@link java.lang.Readable#read} method throws an {@link
* java.io.IOException} then the scanner assumes that the end of the input
* has been reached. The most recent <tt>IOException</tt> thrown by the
* underlying readable can be retrieved via the {@link #ioException} method.
*
* <p>When a <code>Scanner</code> is closed, it will close its input source
* if the source implements the {@link java.io.Closeable} interface.
*
* <p>A <code>Scanner</code> is not safe for multithreaded use without
* external synchronization.
*
* <p>Unless otherwise mentioned, passing a <code>null</code> parameter into
* any method of a <code>Scanner</code> will cause a
* <code>NullPointerException</code> to be thrown.
*
* <p>A scanner will default to interpreting numbers as decimal unless a
* different radix has been set by using the {@link #useRadix} method. The
* {@link #reset} method will reset the value of the scanner's radix to
* <code>10</code> regardless of whether it was previously changed.
*
* <h3> <a name="localized-numbers">Localized numbers</a> </h3>
*
* <p> An instance of this class is capable of scanning numbers in the standard
* formats as well as in the formats of the scanner's locale. A scanner's
* <a name="initial-locale">initial locale </a>is the value returned by the {@link
* java.util.Locale#getDefault(Locale.Category)
* Locale.getDefault(Locale.Category.FORMAT)} method; it may be changed via the {@link
* #useLocale} method. The {@link #reset} method will reset the value of the
* scanner's locale to the initial locale regardless of whether it was
* previously changed.
*
* <p>The localized formats are defined in terms of the following parameters,
* which for a particular locale are taken from that locale's {@link
* java.text.DecimalFormat DecimalFormat} object, <tt>df</tt>, and its and
* {@link java.text.DecimalFormatSymbols DecimalFormatSymbols} object,
* <tt>dfs</tt>.
*
* <blockquote><dl>
* <dt><i>LocalGroupSeparator </i>
* <dd>The character used to separate thousands groups,
* <i>i.e.,</i> <tt>dfs.</tt>{@link
* java.text.DecimalFormatSymbols#getGroupingSeparator
* getGroupingSeparator()}
* <dt><i>LocalDecimalSeparator </i>
* <dd>The character used for the decimal point,
* <i>i.e.,</i> <tt>dfs.</tt>{@link
* java.text.DecimalFormatSymbols#getDecimalSeparator
* getDecimalSeparator()}
* <dt><i>LocalPositivePrefix </i>
* <dd>The string that appears before a positive number (may
* be empty), <i>i.e.,</i> <tt>df.</tt>{@link
* java.text.DecimalFormat#getPositivePrefix
* getPositivePrefix()}
* <dt><i>LocalPositiveSuffix </i>
* <dd>The string that appears after a positive number (may be
* empty), <i>i.e.,</i> <tt>df.</tt>{@link
* java.text.DecimalFormat#getPositiveSuffix
* getPositiveSuffix()}
* <dt><i>LocalNegativePrefix </i>
* <dd>The string that appears before a negative number (may
* be empty), <i>i.e.,</i> <tt>df.</tt>{@link
* java.text.DecimalFormat#getNegativePrefix
* getNegativePrefix()}
* <dt><i>LocalNegativeSuffix </i>
* <dd>The string that appears after a negative number (may be
* empty), <i>i.e.,</i> <tt>df.</tt>{@link
* java.text.DecimalFormat#getNegativeSuffix
* getNegativeSuffix()}
* <dt><i>LocalNaN </i>
* <dd>The string that represents not-a-number for
* floating-point values,
* <i>i.e.,</i> <tt>dfs.</tt>{@link
* java.text.DecimalFormatSymbols#getNaN
* getNaN()}
* <dt><i>LocalInfinity </i>
* <dd>The string that represents infinity for floating-point
* values, <i>i.e.,</i> <tt>dfs.</tt>{@link
* java.text.DecimalFormatSymbols#getInfinity
* getInfinity()}
* </dl></blockquote>
*
* <h4> <a name="number-syntax">Number syntax</a> </h4>
*
* <p> The strings that can be parsed as numbers by an instance of this class
* are specified in terms of the following regular-expression grammar, where
* Rmax is the highest digit in the radix being used (for example, Rmax is 9 in base 10).
*
* <dl>
* <dt><i>NonAsciiDigit</i>:
* <dd>A non-ASCII character c for which
* {@link java.lang.Character#isDigit Character.isDigit}<tt>(c)</tt>
* returns true
*
* <dt><i>Non0Digit</i>:
* <dd><tt>[1-</tt><i>Rmax</i><tt>] | </tt><i>NonASCIIDigit</i>
*
* <dt><i>Digit</i>:
* <dd><tt>[0-</tt><i>Rmax</i><tt>] | </tt><i>NonASCIIDigit</i>
*
* <dt><i>GroupedNumeral</i>:
* <dd><tt>( </tt><i>Non0Digit</i>
* <i>Digit</i><tt>?
* </tt><i>Digit</i><tt>?</tt>
* <dd> <tt>( </tt><i>LocalGroupSeparator</i>
* <i>Digit</i>
* <i>Digit</i>
* <i>Digit</i><tt> )+ )</tt>
*
* <dt><i>Numeral</i>:
* <dd><tt>( ( </tt><i>Digit</i><tt>+ )
* | </tt><i>GroupedNumeral</i><tt> )</tt>
*
* <dt><a name="Integer-regex"><i>Integer</i>:</a>
* <dd><tt>( [-+]? ( </tt><i>Numeral</i><tt>
* ) )</tt>
* <dd><tt>| </tt><i>LocalPositivePrefix</i> <i>Numeral</i>
* <i>LocalPositiveSuffix</i>
* <dd><tt>| </tt><i>LocalNegativePrefix</i> <i>Numeral</i>
* <i>LocalNegativeSuffix</i>
*
* <dt><i>DecimalNumeral</i>:
* <dd><i>Numeral</i>
* <dd><tt>| </tt><i>Numeral</i>
* <i>LocalDecimalSeparator</i>
* <i>Digit</i><tt>*</tt>
* <dd><tt>| </tt><i>LocalDecimalSeparator</i>
* <i>Digit</i><tt>+</tt>
*
* <dt><i>Exponent</i>:
* <dd><tt>( [eE] [+-]? </tt><i>Digit</i><tt>+ )</tt>
*
* <dt><a name="Decimal-regex"><i>Decimal</i>:</a>
* <dd><tt>( [-+]? </tt><i>DecimalNumeral</i>
* <i>Exponent</i><tt>? )</tt>
* <dd><tt>| </tt><i>LocalPositivePrefix</i>
* <i>DecimalNumeral</i>
* <i>LocalPositiveSuffix</i>
* <i>Exponent</i><tt>?</tt>
* <dd><tt>| </tt><i>LocalNegativePrefix</i>
* <i>DecimalNumeral</i>
* <i>LocalNegativeSuffix</i>
* <i>Exponent</i><tt>?</tt>
*
* <dt><i>HexFloat</i>:
* <dd><tt>[-+]? 0[xX][0-9a-fA-F]*\.[0-9a-fA-F]+
* ([pP][-+]?[0-9]+)?</tt>
*
* <dt><i>NonNumber</i>:
* <dd><tt>NaN
* | </tt><i>LocalNan</i><tt>
* | Infinity
* | </tt><i>LocalInfinity</i>
*
* <dt><i>SignedNonNumber</i>:
* <dd><tt>( [-+]? </tt><i>NonNumber</i><tt> )</tt>
* <dd><tt>| </tt><i>LocalPositivePrefix</i>
* <i>NonNumber</i>
* <i>LocalPositiveSuffix</i>
* <dd><tt>| </tt><i>LocalNegativePrefix</i>
* <i>NonNumber</i>
* <i>LocalNegativeSuffix</i>
*
* <dt><a name="Float-regex"><i>Float</i></a>:
* <dd><i>Decimal</i>
* <tt>| </tt><i>HexFloat</i>
* <tt>| </tt><i>SignedNonNumber</i>
*
* </dl>
* <p>Whitespace is not significant in the above regular expressions.
*
* @since 1.5
*/
public final class
Scanner implements
Iterator<
String>,
Closeable {
// Internal buffer used to hold input
private
CharBuffer buf;
// Size of internal character buffer
private static final int
BUFFER_SIZE = 1024; // change to 1024;
// The index into the buffer currently held by the Scanner
private int
position;
// Internal matcher used for finding delimiters
private
Matcher matcher;
// Pattern used to delimit tokens
private
Pattern delimPattern;
// Pattern found in last hasNext operation
private
Pattern hasNextPattern;
// Position after last hasNext operation
private int
hasNextPosition;
// Result after last hasNext operation
private
String hasNextResult;
// The input source
private
Readable source;
// Boolean is true if source is done
private boolean
sourceClosed = false;
// Boolean indicating more input is required
private boolean
needInput = false;
// Boolean indicating if a delim has been skipped this operation
private boolean
skipped = false;
// A store of a position that the scanner may fall back to
private int
savedScannerPosition = -1;
// A cache of the last primitive type scanned
private
Object typeCache = null;
// Boolean indicating if a match result is available
private boolean
matchValid = false;
// Boolean indicating if this scanner has been closed
private boolean
closed = false;
// The current radix used by this scanner
private int
radix = 10;
// The default radix for this scanner
private int
defaultRadix = 10;
// The locale used by this scanner
private
Locale locale = null;
// A cache of the last few recently used Patterns
private
LRUCache<
String,
Pattern>
patternCache =
new
LRUCache<
String,
Pattern>(7) {
protected
Pattern create(
String s) {
return
Pattern.
compile(
s);
}
protected boolean
hasName(
Pattern p,
String s) {
return
p.
pattern().
equals(
s);
}
};
// A holder of the last IOException encountered
private
IOException lastException;
// A pattern for java whitespace
private static
Pattern WHITESPACE_PATTERN =
Pattern.
compile(
"\\p{javaWhitespace}+");
// A pattern for any token
private static
Pattern FIND_ANY_PATTERN =
Pattern.
compile("(?s).*");
// A pattern for non-ASCII digits
private static
Pattern NON_ASCII_DIGIT =
Pattern.
compile(
"[\\p{javaDigit}&&[^0-9]]");
// Fields and methods to support scanning primitive types
/**
* Locale dependent values used to scan numbers
*/
private
String groupSeparator = "\\,";
private
String decimalSeparator = "\\.";
private
String nanString = "NaN";
private
String infinityString = "Infinity";
private
String positivePrefix = "";
private
String negativePrefix = "\\-";
private
String positiveSuffix = "";
private
String negativeSuffix = "";
/**
* Fields and an accessor method to match booleans
*/
private static volatile
Pattern boolPattern;
private static final
String BOOLEAN_PATTERN = "true|false";
private static
Pattern boolPattern() {
Pattern bp =
boolPattern;
if (
bp == null)
boolPattern =
bp =
Pattern.
compile(
BOOLEAN_PATTERN,
Pattern.
CASE_INSENSITIVE);
return
bp;
}
/**
* Fields and methods to match bytes, shorts, ints, and longs
*/
private
Pattern integerPattern;
private
String digits = "0123456789abcdefghijklmnopqrstuvwxyz";
private
String non0Digit = "[\\p{javaDigit}&&[^0]]";
private int
SIMPLE_GROUP_INDEX = 5;
private
String buildIntegerPatternString() {
String radixDigits =
digits.
substring(0,
radix);
// \\p{javaDigit} is not guaranteed to be appropriate
// here but what can we do? The final authority will be
// whatever parse method is invoked, so ultimately the
// Scanner will do the right thing
String digit = "((?i)["+
radixDigits+"]|\\p{javaDigit})";
String groupedNumeral = "("+
non0Digit+
digit+"?"+
digit+"?("+
groupSeparator+
digit+
digit+
digit+")+)";
// digit++ is the possessive form which is necessary for reducing
// backtracking that would otherwise cause unacceptable performance
String numeral = "(("+
digit+"++)|"+
groupedNumeral+")";
String javaStyleInteger = "([-+]?(" +
numeral + "))";
String negativeInteger =
negativePrefix +
numeral +
negativeSuffix;
String positiveInteger =
positivePrefix +
numeral +
positiveSuffix;
return "("+
javaStyleInteger + ")|(" +
positiveInteger + ")|(" +
negativeInteger + ")";
}
private
Pattern integerPattern() {
if (
integerPattern == null) {
integerPattern =
patternCache.
forName(
buildIntegerPatternString());
}
return
integerPattern;
}
/**
* Fields and an accessor method to match line separators
*/
private static volatile
Pattern separatorPattern;
private static volatile
Pattern linePattern;
private static final
String LINE_SEPARATOR_PATTERN =
"\r\n|[\n\r\u2028\u2029\u0085]";
private static final
String LINE_PATTERN = ".*("+
LINE_SEPARATOR_PATTERN+")|.+$";
private static
Pattern separatorPattern() {
Pattern sp =
separatorPattern;
if (
sp == null)
separatorPattern =
sp =
Pattern.
compile(
LINE_SEPARATOR_PATTERN);
return
sp;
}
private static
Pattern linePattern() {
Pattern lp =
linePattern;
if (
lp == null)
linePattern =
lp =
Pattern.
compile(
LINE_PATTERN);
return
lp;
}
/**
* Fields and methods to match floats and doubles
*/
private
Pattern floatPattern;
private
Pattern decimalPattern;
private void
buildFloatAndDecimalPattern() {
// \\p{javaDigit} may not be perfect, see above
String digit = "([0-9]|(\\p{javaDigit}))";
String exponent = "([eE][+-]?"+
digit+"+)?";
String groupedNumeral = "("+
non0Digit+
digit+"?"+
digit+"?("+
groupSeparator+
digit+
digit+
digit+")+)";
// Once again digit++ is used for performance, as above
String numeral = "(("+
digit+"++)|"+
groupedNumeral+")";
String decimalNumeral = "("+
numeral+"|"+
numeral +
decimalSeparator +
digit + "*+|"+
decimalSeparator +
digit + "++)";
String nonNumber = "(NaN|"+
nanString+"|Infinity|"+
infinityString+")";
String positiveFloat = "(" +
positivePrefix +
decimalNumeral +
positiveSuffix +
exponent + ")";
String negativeFloat = "(" +
negativePrefix +
decimalNumeral +
negativeSuffix +
exponent + ")";
String decimal = "(([-+]?" +
decimalNumeral +
exponent + ")|"+
positiveFloat + "|" +
negativeFloat + ")";
String hexFloat =
"[-+]?0[xX][0-9a-fA-F]*\\.[0-9a-fA-F]+([pP][-+]?[0-9]+)?";
String positiveNonNumber = "(" +
positivePrefix +
nonNumber +
positiveSuffix + ")";
String negativeNonNumber = "(" +
negativePrefix +
nonNumber +
negativeSuffix + ")";
String signedNonNumber = "(([-+]?"+
nonNumber+")|" +
positiveNonNumber + "|" +
negativeNonNumber + ")";
floatPattern =
Pattern.
compile(
decimal + "|" +
hexFloat + "|" +
signedNonNumber);
decimalPattern =
Pattern.
compile(
decimal);
}
private
Pattern floatPattern() {
if (
floatPattern == null) {
buildFloatAndDecimalPattern();
}
return
floatPattern;
}
private
Pattern decimalPattern() {
if (
decimalPattern == null) {
buildFloatAndDecimalPattern();
}
return
decimalPattern;
}
// Constructors
/**
* Constructs a <code>Scanner</code> that returns values scanned
* from the specified source delimited by the specified pattern.
*
* @param source A character source implementing the Readable interface
* @param pattern A delimiting pattern
*/
private
Scanner(
Readable source,
Pattern pattern) {
assert
source != null : "source should not be null";
assert
pattern != null : "pattern should not be null";
this.
source =
source;
delimPattern =
pattern;
buf =
CharBuffer.
allocate(
BUFFER_SIZE);
buf.
limit(0);
matcher =
delimPattern.
matcher(
buf);
matcher.
useTransparentBounds(true);
matcher.
useAnchoringBounds(false);
useLocale(
Locale.
getDefault(
Locale.
Category.
FORMAT));
}
/**
* Constructs a new <code>Scanner</code> that produces values scanned
* from the specified source.
*
* @param source A character source implementing the {@link Readable}
* interface
*/
public
Scanner(
Readable source) {
this(
Objects.
requireNonNull(
source, "source"),
WHITESPACE_PATTERN);
}
/**
* Constructs a new <code>Scanner</code> that produces values scanned
* from the specified input stream. Bytes from the stream are converted
* into characters using the underlying platform's
* {@linkplain java.nio.charset.Charset#defaultCharset() default charset}.
*
* @param source An input stream to be scanned
*/
public
Scanner(
InputStream source) {
this(new
InputStreamReader(
source),
WHITESPACE_PATTERN);
}
/**
* Constructs a new <code>Scanner</code> that produces values scanned
* from the specified input stream. Bytes from the stream are converted
* into characters using the specified charset.
*
* @param source An input stream to be scanned
* @param charsetName The encoding type used to convert bytes from the
* stream into characters to be scanned
* @throws IllegalArgumentException if the specified character set
* does not exist
*/
public
Scanner(
InputStream source,
String charsetName) {
this(
makeReadable(
Objects.
requireNonNull(
source, "source"),
toCharset(
charsetName)),
WHITESPACE_PATTERN);
}
/**
* Returns a charset object for the given charset name.
* @throws NullPointerException is csn is null
* @throws IllegalArgumentException if the charset is not supported
*/
private static
Charset toCharset(
String csn) {
Objects.
requireNonNull(
csn, "charsetName");
try {
return
Charset.
forName(
csn);
} catch (
IllegalCharsetNameException|
UnsupportedCharsetException e) {
// IllegalArgumentException should be thrown
throw new
IllegalArgumentException(
e);
}
}
private static
Readable makeReadable(
InputStream source,
Charset charset) {
return new
InputStreamReader(
source,
charset);
}
/**
* Constructs a new <code>Scanner</code> that produces values scanned
* from the specified file. Bytes from the file are converted into
* characters using the underlying platform's
* {@linkplain java.nio.charset.Charset#defaultCharset() default charset}.
*
* @param source A file to be scanned
* @throws FileNotFoundException if source is not found
*/
public
Scanner(
File source) throws
FileNotFoundException {
this((
ReadableByteChannel)(new
FileInputStream(
source).
getChannel()));
}
/**
* Constructs a new <code>Scanner</code> that produces values scanned
* from the specified file. Bytes from the file are converted into
* characters using the specified charset.
*
* @param source A file to be scanned
* @param charsetName The encoding type used to convert bytes from the file
* into characters to be scanned
* @throws FileNotFoundException if source is not found
* @throws IllegalArgumentException if the specified encoding is
* not found
*/
public
Scanner(
File source,
String charsetName)
throws
FileNotFoundException
{
this(
Objects.
requireNonNull(
source),
toDecoder(
charsetName));
}
private
Scanner(
File source,
CharsetDecoder dec)
throws
FileNotFoundException
{
this(
makeReadable((
ReadableByteChannel)(new
FileInputStream(
source).
getChannel()),
dec));
}
private static
CharsetDecoder toDecoder(
String charsetName) {
Objects.
requireNonNull(
charsetName, "charsetName");
try {
return
Charset.
forName(
charsetName).
newDecoder();
} catch (
IllegalCharsetNameException|
UnsupportedCharsetException unused) {
throw new
IllegalArgumentException(
charsetName);
}
}
private static
Readable makeReadable(
ReadableByteChannel source,
CharsetDecoder dec) {
return
Channels.
newReader(
source,
dec, -1);
}
/**
* Constructs a new <code>Scanner</code> that produces values scanned
* from the specified file. Bytes from the file are converted into
* characters using the underlying platform's
* {@linkplain java.nio.charset.Charset#defaultCharset() default charset}.
*
* @param source
* the path to the file to be scanned
* @throws IOException
* if an I/O error occurs opening source
*
* @since 1.7
*/
public
Scanner(
Path source)
throws
IOException
{
this(
Files.
newInputStream(
source));
}
/**
* Constructs a new <code>Scanner</code> that produces values scanned
* from the specified file. Bytes from the file are converted into
* characters using the specified charset.
*
* @param source
* the path to the file to be scanned
* @param charsetName
* The encoding type used to convert bytes from the file
* into characters to be scanned
* @throws IOException
* if an I/O error occurs opening source
* @throws IllegalArgumentException
* if the specified encoding is not found
* @since 1.7
*/
public
Scanner(
Path source,
String charsetName) throws
IOException {
this(
Objects.
requireNonNull(
source),
toCharset(
charsetName));
}
private
Scanner(
Path source,
Charset charset) throws
IOException {
this(
makeReadable(
Files.
newInputStream(
source),
charset));
}
/**
* Constructs a new <code>Scanner</code> that produces values scanned
* from the specified string.
*
* @param source A string to scan
*/
public
Scanner(
String source) {
this(new
StringReader(
source),
WHITESPACE_PATTERN);
}
/**
* Constructs a new <code>Scanner</code> that produces values scanned
* from the specified channel. Bytes from the source are converted into
* characters using the underlying platform's
* {@linkplain java.nio.charset.Charset#defaultCharset() default charset}.
*
* @param source A channel to scan
*/
public
Scanner(
ReadableByteChannel source) {
this(
makeReadable(
Objects.
requireNonNull(
source, "source")),
WHITESPACE_PATTERN);
}
private static
Readable makeReadable(
ReadableByteChannel source) {
return
makeReadable(
source,
Charset.
defaultCharset().
newDecoder());
}
/**
* Constructs a new <code>Scanner</code> that produces values scanned
* from the specified channel. Bytes from the source are converted into
* characters using the specified charset.
*
* @param source A channel to scan
* @param charsetName The encoding type used to convert bytes from the
* channel into characters to be scanned
* @throws IllegalArgumentException if the specified character set
* does not exist
*/
public
Scanner(
ReadableByteChannel source,
String charsetName) {
this(
makeReadable(
Objects.
requireNonNull(
source, "source"),
toDecoder(
charsetName)),
WHITESPACE_PATTERN);
}
// Private primitives used to support scanning
private void
saveState() {
savedScannerPosition =
position;
}
private void
revertState() {
this.
position =
savedScannerPosition;
savedScannerPosition = -1;
skipped = false;
}
private boolean
revertState(boolean
b) {
this.
position =
savedScannerPosition;
savedScannerPosition = -1;
skipped = false;
return
b;
}
private void
cacheResult() {
hasNextResult =
matcher.
group();
hasNextPosition =
matcher.
end();
hasNextPattern =
matcher.
pattern();
}
private void
cacheResult(
String result) {
hasNextResult =
result;
hasNextPosition =
matcher.
end();
hasNextPattern =
matcher.
pattern();
}
// Clears both regular cache and type cache
private void
clearCaches() {
hasNextPattern = null;
typeCache = null;
}
// Also clears both the regular cache and the type cache
private
String getCachedResult() {
position =
hasNextPosition;
hasNextPattern = null;
typeCache = null;
return
hasNextResult;
}
// Also clears both the regular cache and the type cache
private void
useTypeCache() {
if (
closed)
throw new
IllegalStateException("Scanner closed");
position =
hasNextPosition;
hasNextPattern = null;
typeCache = null;
}
// Tries to read more input. May block.
private void
readInput() {
if (
buf.
limit() ==
buf.
capacity())
makeSpace();
// Prepare to receive data
int
p =
buf.
position();
buf.
position(
buf.
limit());
buf.
limit(
buf.
capacity());
int
n = 0;
try {
n =
source.
read(
buf);
} catch (
IOException ioe) {
lastException =
ioe;
n = -1;
}
if (
n == -1) {
sourceClosed = true;
needInput = false;
}
if (
n > 0)
needInput = false;
// Restore current position and limit for reading
buf.
limit(
buf.
position());
buf.
position(
p);
}
// After this method is called there will either be an exception
// or else there will be space in the buffer
private boolean
makeSpace() {
clearCaches();
int
offset =
savedScannerPosition == -1 ?
position :
savedScannerPosition;
buf.
position(
offset);
// Gain space by compacting buffer
if (
offset > 0) {
buf.
compact();
translateSavedIndexes(
offset);
position -=
offset;
buf.
flip();
return true;
}
// Gain space by growing buffer
int
newSize =
buf.
capacity() * 2;
CharBuffer newBuf =
CharBuffer.
allocate(
newSize);
newBuf.
put(
buf);
newBuf.
flip();
translateSavedIndexes(
offset);
position -=
offset;
buf =
newBuf;
matcher.
reset(
buf);
return true;
}
// When a buffer compaction/reallocation occurs the saved indexes must
// be modified appropriately
private void
translateSavedIndexes(int
offset) {
if (
savedScannerPosition != -1)
savedScannerPosition -=
offset;
}
// If we are at the end of input then NoSuchElement;
// If there is still input left then InputMismatch
private void
throwFor() {
skipped = false;
if ((
sourceClosed) && (
position ==
buf.
limit()))
throw new
NoSuchElementException();
else
throw new
InputMismatchException();
}
// Returns true if a complete token or partial token is in the buffer.
// It is not necessary to find a complete token since a partial token
// means that there will be another token with or without more input.
private boolean
hasTokenInBuffer() {
matchValid = false;
matcher.
usePattern(
delimPattern);
matcher.
region(
position,
buf.
limit());
// Skip delims first
if (
matcher.
lookingAt())
position =
matcher.
end();
// If we are sitting at the end, no more tokens in buffer
if (
position ==
buf.
limit())
return false;
return true;
}
/*
* Returns a "complete token" that matches the specified pattern
*
* A token is complete if surrounded by delims; a partial token
* is prefixed by delims but not postfixed by them
*
* The position is advanced to the end of that complete token
*
* Pattern == null means accept any token at all
*
* Triple return:
* 1. valid string means it was found
* 2. null with needInput=false means we won't ever find it
* 3. null with needInput=true means try again after readInput
*/
private
String getCompleteTokenInBuffer(
Pattern pattern) {
matchValid = false;
// Skip delims first
matcher.
usePattern(
delimPattern);
if (!
skipped) { // Enforcing only one skip of leading delims
matcher.
region(
position,
buf.
limit());
if (
matcher.
lookingAt()) {
// If more input could extend the delimiters then we must wait
// for more input
if (
matcher.
hitEnd() && !
sourceClosed) {
needInput = true;
return null;
}
// The delims were whole and the matcher should skip them
skipped = true;
position =
matcher.
end();
}
}
// If we are sitting at the end, no more tokens in buffer
if (
position ==
buf.
limit()) {
if (
sourceClosed)
return null;
needInput = true;
return null;
}
// Must look for next delims. Simply attempting to match the
// pattern at this point may find a match but it might not be
// the first longest match because of missing input, or it might
// match a partial token instead of the whole thing.
// Then look for next delims
matcher.
region(
position,
buf.
limit());
boolean
foundNextDelim =
matcher.
find();
if (
foundNextDelim && (
matcher.
end() ==
position)) {
// Zero length delimiter match; we should find the next one
// using the automatic advance past a zero length match;
// Otherwise we have just found the same one we just skipped
foundNextDelim =
matcher.
find();
}
if (
foundNextDelim) {
// In the rare case that more input could cause the match
// to be lost and there is more input coming we must wait
// for more input. Note that hitting the end is okay as long
// as the match cannot go away. It is the beginning of the
// next delims we want to be sure about, we don't care if
// they potentially extend further.
if (
matcher.
requireEnd() && !
sourceClosed) {
needInput = true;
return null;
}
int
tokenEnd =
matcher.
start();
// There is a complete token.
if (
pattern == null) {
// Must continue with match to provide valid MatchResult
pattern =
FIND_ANY_PATTERN;
}
// Attempt to match against the desired pattern
matcher.
usePattern(
pattern);
matcher.
region(
position,
tokenEnd);
if (
matcher.
matches()) {
String s =
matcher.
group();
position =
matcher.
end();
return
s;
} else { // Complete token but it does not match
return null;
}
}
// If we can't find the next delims but no more input is coming,
// then we can treat the remainder as a whole token
if (
sourceClosed) {
if (
pattern == null) {
// Must continue with match to provide valid MatchResult
pattern =
FIND_ANY_PATTERN;
}
// Last token; Match the pattern here or throw
matcher.
usePattern(
pattern);
matcher.
region(
position,
buf.
limit());
if (
matcher.
matches()) {
String s =
matcher.
group();
position =
matcher.
end();
return
s;
}
// Last piece does not match
return null;
}
// There is a partial token in the buffer; must read more
// to complete it
needInput = true;
return null;
}
// Finds the specified pattern in the buffer up to horizon.
// Returns a match for the specified input pattern.
private
String findPatternInBuffer(
Pattern pattern, int
horizon) {
matchValid = false;
matcher.
usePattern(
pattern);
int
bufferLimit =
buf.
limit();
int
horizonLimit = -1;
int
searchLimit =
bufferLimit;
if (
horizon > 0) {
horizonLimit =
position +
horizon;
if (
horizonLimit <
bufferLimit)
searchLimit =
horizonLimit;
}
matcher.
region(
position,
searchLimit);
if (
matcher.
find()) {
if (
matcher.
hitEnd() && (!
sourceClosed)) {
// The match may be longer if didn't hit horizon or real end
if (
searchLimit !=
horizonLimit) {
// Hit an artificial end; try to extend the match
needInput = true;
return null;
}
// The match could go away depending on what is next
if ((
searchLimit ==
horizonLimit) &&
matcher.
requireEnd()) {
// Rare case: we hit the end of input and it happens
// that it is at the horizon and the end of input is
// required for the match.
needInput = true;
return null;
}
}
// Did not hit end, or hit real end, or hit horizon
position =
matcher.
end();
return
matcher.
group();
}
if (
sourceClosed)
return null;
// If there is no specified horizon, or if we have not searched
// to the specified horizon yet, get more input
if ((
horizon == 0) || (
searchLimit !=
horizonLimit))
needInput = true;
return null;
}
// Returns a match for the specified input pattern anchored at
// the current position
private
String matchPatternInBuffer(
Pattern pattern) {
matchValid = false;
matcher.
usePattern(
pattern);
matcher.
region(
position,
buf.
limit());
if (
matcher.
lookingAt()) {
if (
matcher.
hitEnd() && (!
sourceClosed)) {
// Get more input and try again
needInput = true;
return null;
}
position =
matcher.
end();
return
matcher.
group();
}
if (
sourceClosed)
return null;
// Read more to find pattern
needInput = true;
return null;
}
// Throws if the scanner is closed
private void
ensureOpen() {
if (
closed)
throw new
IllegalStateException("Scanner closed");
}
// Public methods
/**
* Closes this scanner.
*
* <p> If this scanner has not yet been closed then if its underlying
* {@linkplain java.lang.Readable readable} also implements the {@link
* java.io.Closeable} interface then the readable's <tt>close</tt> method
* will be invoked. If this scanner is already closed then invoking this
* method will have no effect.
*
* <p>Attempting to perform search operations after a scanner has
* been closed will result in an {@link IllegalStateException}.
*
*/
public void
close() {
if (
closed)
return;
if (
source instanceof
Closeable) {
try {
((
Closeable)
source).
close();
} catch (
IOException ioe) {
lastException =
ioe;
}
}
sourceClosed = true;
source = null;
closed = true;
}
/**
* Returns the <code>IOException</code> last thrown by this
* <code>Scanner</code>'s underlying <code>Readable</code>. This method
* returns <code>null</code> if no such exception exists.
*
* @return the last exception thrown by this scanner's readable
*/
public
IOException ioException() {
return
lastException;
}
/**
* Returns the <code>Pattern</code> this <code>Scanner</code> is currently
* using to match delimiters.
*
* @return this scanner's delimiting pattern.
*/
public
Pattern delimiter() {
return
delimPattern;
}
/**
* Sets this scanner's delimiting pattern to the specified pattern.
*
* @param pattern A delimiting pattern
* @return this scanner
*/
public
Scanner useDelimiter(
Pattern pattern) {
delimPattern =
pattern;
return this;
}
/**
* Sets this scanner's delimiting pattern to a pattern constructed from
* the specified <code>String</code>.
*
* <p> An invocation of this method of the form
* <tt>useDelimiter(pattern)</tt> behaves in exactly the same way as the
* invocation <tt>useDelimiter(Pattern.compile(pattern))</tt>.
*
* <p> Invoking the {@link #reset} method will set the scanner's delimiter
* to the <a href= "#default-delimiter">default</a>.
*
* @param pattern A string specifying a delimiting pattern
* @return this scanner
*/
public
Scanner useDelimiter(
String pattern) {
delimPattern =
patternCache.
forName(
pattern);
return this;
}
/**
* Returns this scanner's locale.
*
* <p>A scanner's locale affects many elements of its default
* primitive matching regular expressions; see
* <a href= "#localized-numbers">localized numbers</a> above.
*
* @return this scanner's locale
*/
public
Locale locale() {
return this.
locale;
}
/**
* Sets this scanner's locale to the specified locale.
*
* <p>A scanner's locale affects many elements of its default
* primitive matching regular expressions; see
* <a href= "#localized-numbers">localized numbers</a> above.
*
* <p>Invoking the {@link #reset} method will set the scanner's locale to
* the <a href= "#initial-locale">initial locale</a>.
*
* @param locale A string specifying the locale to use
* @return this scanner
*/
public
Scanner useLocale(
Locale locale) {
if (
locale.
equals(this.
locale))
return this;
this.
locale =
locale;
DecimalFormat df =
(
DecimalFormat)
NumberFormat.
getNumberInstance(
locale);
DecimalFormatSymbols dfs =
DecimalFormatSymbols.
getInstance(
locale);
// These must be literalized to avoid collision with regex
// metacharacters such as dot or parenthesis
groupSeparator = "\\" +
dfs.
getGroupingSeparator();
decimalSeparator = "\\" +
dfs.
getDecimalSeparator();
// Quoting the nonzero length locale-specific things
// to avoid potential conflict with metacharacters
nanString = "\\Q" +
dfs.
getNaN() + "\\E";
infinityString = "\\Q" +
dfs.
getInfinity() + "\\E";
positivePrefix =
df.
getPositivePrefix();
if (
positivePrefix.
length() > 0)
positivePrefix = "\\Q" +
positivePrefix + "\\E";
negativePrefix =
df.
getNegativePrefix();
if (
negativePrefix.
length() > 0)
negativePrefix = "\\Q" +
negativePrefix + "\\E";
positiveSuffix =
df.
getPositiveSuffix();
if (
positiveSuffix.
length() > 0)
positiveSuffix = "\\Q" +
positiveSuffix + "\\E";
negativeSuffix =
df.
getNegativeSuffix();
if (
negativeSuffix.
length() > 0)
negativeSuffix = "\\Q" +
negativeSuffix + "\\E";
// Force rebuilding and recompilation of locale dependent
// primitive patterns
integerPattern = null;
floatPattern = null;
return this;
}
/**
* Returns this scanner's default radix.
*
* <p>A scanner's radix affects elements of its default
* number matching regular expressions; see
* <a href= "#localized-numbers">localized numbers</a> above.
*
* @return the default radix of this scanner
*/
public int
radix() {
return this.
defaultRadix;
}
/**
* Sets this scanner's default radix to the specified radix.
*
* <p>A scanner's radix affects elements of its default
* number matching regular expressions; see
* <a href= "#localized-numbers">localized numbers</a> above.
*
* <p>If the radix is less than <code>Character.MIN_RADIX</code>
* or greater than <code>Character.MAX_RADIX</code>, then an
* <code>IllegalArgumentException</code> is thrown.
*
* <p>Invoking the {@link #reset} method will set the scanner's radix to
* <code>10</code>.
*
* @param radix The radix to use when scanning numbers
* @return this scanner
* @throws IllegalArgumentException if radix is out of range
*/
public
Scanner useRadix(int
radix) {
if ((
radix <
Character.
MIN_RADIX) || (
radix >
Character.
MAX_RADIX))
throw new
IllegalArgumentException("radix:"+
radix);
if (this.
defaultRadix ==
radix)
return this;
this.
defaultRadix =
radix;
// Force rebuilding and recompilation of radix dependent patterns
integerPattern = null;
return this;
}
// The next operation should occur in the specified radix but
// the default is left untouched.
private void
setRadix(int
radix) {
if (this.
radix !=
radix) {
// Force rebuilding and recompilation of radix dependent patterns
integerPattern = null;
this.
radix =
radix;
}
}
/**
* Returns the match result of the last scanning operation performed
* by this scanner. This method throws <code>IllegalStateException</code>
* if no match has been performed, or if the last match was
* not successful.
*
* <p>The various <code>next</code>methods of <code>Scanner</code>
* make a match result available if they complete without throwing an
* exception. For instance, after an invocation of the {@link #nextInt}
* method that returned an int, this method returns a
* <code>MatchResult</code> for the search of the
* <a href="#Integer-regex"><i>Integer</i></a> regular expression
* defined above. Similarly the {@link #findInLine},
* {@link #findWithinHorizon}, and {@link #skip} methods will make a
* match available if they succeed.
*
* @return a match result for the last match operation
* @throws IllegalStateException If no match result is available
*/
public
MatchResult match() {
if (!
matchValid)
throw new
IllegalStateException("No match result available");
return
matcher.
toMatchResult();
}
/**
* <p>Returns the string representation of this <code>Scanner</code>. The
* string representation of a <code>Scanner</code> contains information
* that may be useful for debugging. The exact format is unspecified.
*
* @return The string representation of this scanner
*/
public
String toString() {
StringBuilder sb = new
StringBuilder();
sb.
append("java.util.Scanner");
sb.
append("[delimiters=" +
delimPattern + "]");
sb.
append("[position=" +
position + "]");
sb.
append("[match valid=" +
matchValid + "]");
sb.
append("[need input=" +
needInput + "]");
sb.
append("[source closed=" +
sourceClosed + "]");
sb.
append("[skipped=" +
skipped + "]");
sb.
append("[group separator=" +
groupSeparator + "]");
sb.
append("[decimal separator=" +
decimalSeparator + "]");
sb.
append("[positive prefix=" +
positivePrefix + "]");
sb.
append("[negative prefix=" +
negativePrefix + "]");
sb.
append("[positive suffix=" +
positiveSuffix + "]");
sb.
append("[negative suffix=" +
negativeSuffix + "]");
sb.
append("[NaN string=" +
nanString + "]");
sb.
append("[infinity string=" +
infinityString + "]");
return
sb.
toString();
}
/**
* Returns true if this scanner has another token in its input.
* This method may block while waiting for input to scan.
* The scanner does not advance past any input.
*
* @return true if and only if this scanner has another token
* @throws IllegalStateException if this scanner is closed
* @see java.util.Iterator
*/
public boolean
hasNext() {
ensureOpen();
saveState();
while (!
sourceClosed) {
if (
hasTokenInBuffer())
return
revertState(true);
readInput();
}
boolean
result =
hasTokenInBuffer();
return
revertState(
result);
}
/**
* Finds and returns the next complete token from this scanner.
* A complete token is preceded and followed by input that matches
* the delimiter pattern. This method may block while waiting for input
* to scan, even if a previous invocation of {@link #hasNext} returned
* <code>true</code>.
*
* @return the next token
* @throws NoSuchElementException if no more tokens are available
* @throws IllegalStateException if this scanner is closed
* @see java.util.Iterator
*/
public
String next() {
ensureOpen();
clearCaches();
while (true) {
String token =
getCompleteTokenInBuffer(null);
if (
token != null) {
matchValid = true;
skipped = false;
return
token;
}
if (
needInput)
readInput();
else
throwFor();
}
}
/**
* The remove operation is not supported by this implementation of
* <code>Iterator</code>.
*
* @throws UnsupportedOperationException if this method is invoked.
* @see java.util.Iterator
*/
public void
remove() {
throw new
UnsupportedOperationException();
}
/**
* Returns true if the next token matches the pattern constructed from the
* specified string. The scanner does not advance past any input.
*
* <p> An invocation of this method of the form <tt>hasNext(pattern)</tt>
* behaves in exactly the same way as the invocation
* <tt>hasNext(Pattern.compile(pattern))</tt>.
*
* @param pattern a string specifying the pattern to scan
* @return true if and only if this scanner has another token matching
* the specified pattern
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNext(
String pattern) {
return
hasNext(
patternCache.
forName(
pattern));
}
/**
* Returns the next token if it matches the pattern constructed from the
* specified string. If the match is successful, the scanner advances
* past the input that matched the pattern.
*
* <p> An invocation of this method of the form <tt>next(pattern)</tt>
* behaves in exactly the same way as the invocation
* <tt>next(Pattern.compile(pattern))</tt>.
*
* @param pattern a string specifying the pattern to scan
* @return the next token
* @throws NoSuchElementException if no such tokens are available
* @throws IllegalStateException if this scanner is closed
*/
public
String next(
String pattern) {
return
next(
patternCache.
forName(
pattern));
}
/**
* Returns true if the next complete token matches the specified pattern.
* A complete token is prefixed and postfixed by input that matches
* the delimiter pattern. This method may block while waiting for input.
* The scanner does not advance past any input.
*
* @param pattern the pattern to scan for
* @return true if and only if this scanner has another token matching
* the specified pattern
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNext(
Pattern pattern) {
ensureOpen();
if (
pattern == null)
throw new
NullPointerException();
hasNextPattern = null;
saveState();
while (true) {
if (
getCompleteTokenInBuffer(
pattern) != null) {
matchValid = true;
cacheResult();
return
revertState(true);
}
if (
needInput)
readInput();
else
return
revertState(false);
}
}
/**
* Returns the next token if it matches the specified pattern. This
* method may block while waiting for input to scan, even if a previous
* invocation of {@link #hasNext(Pattern)} returned <code>true</code>.
* If the match is successful, the scanner advances past the input that
* matched the pattern.
*
* @param pattern the pattern to scan for
* @return the next token
* @throws NoSuchElementException if no more tokens are available
* @throws IllegalStateException if this scanner is closed
*/
public
String next(
Pattern pattern) {
ensureOpen();
if (
pattern == null)
throw new
NullPointerException();
// Did we already find this pattern?
if (
hasNextPattern ==
pattern)
return
getCachedResult();
clearCaches();
// Search for the pattern
while (true) {
String token =
getCompleteTokenInBuffer(
pattern);
if (
token != null) {
matchValid = true;
skipped = false;
return
token;
}
if (
needInput)
readInput();
else
throwFor();
}
}
/**
* Returns true if there is another line in the input of this scanner.
* This method may block while waiting for input. The scanner does not
* advance past any input.
*
* @return true if and only if this scanner has another line of input
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextLine() {
saveState();
String result =
findWithinHorizon(
linePattern(), 0);
if (
result != null) {
MatchResult mr = this.
match();
String lineSep =
mr.
group(1);
if (
lineSep != null) {
result =
result.
substring(0,
result.
length() -
lineSep.
length());
cacheResult(
result);
} else {
cacheResult();
}
}
revertState();
return (
result != null);
}
/**
* Advances this scanner past the current line and returns the input
* that was skipped.
*
* This method returns the rest of the current line, excluding any line
* separator at the end. The position is set to the beginning of the next
* line.
*
* <p>Since this method continues to search through the input looking
* for a line separator, it may buffer all of the input searching for
* the line to skip if no line separators are present.
*
* @return the line that was skipped
* @throws NoSuchElementException if no line was found
* @throws IllegalStateException if this scanner is closed
*/
public
String nextLine() {
if (
hasNextPattern ==
linePattern())
return
getCachedResult();
clearCaches();
String result =
findWithinHorizon(
linePattern, 0);
if (
result == null)
throw new
NoSuchElementException("No line found");
MatchResult mr = this.
match();
String lineSep =
mr.
group(1);
if (
lineSep != null)
result =
result.
substring(0,
result.
length() -
lineSep.
length());
if (
result == null)
throw new
NoSuchElementException();
else
return
result;
}
// Public methods that ignore delimiters
/**
* Attempts to find the next occurrence of a pattern constructed from the
* specified string, ignoring delimiters.
*
* <p>An invocation of this method of the form <tt>findInLine(pattern)</tt>
* behaves in exactly the same way as the invocation
* <tt>findInLine(Pattern.compile(pattern))</tt>.
*
* @param pattern a string specifying the pattern to search for
* @return the text that matched the specified pattern
* @throws IllegalStateException if this scanner is closed
*/
public
String findInLine(
String pattern) {
return
findInLine(
patternCache.
forName(
pattern));
}
/**
* Attempts to find the next occurrence of the specified pattern ignoring
* delimiters. If the pattern is found before the next line separator, the
* scanner advances past the input that matched and returns the string that
* matched the pattern.
* If no such pattern is detected in the input up to the next line
* separator, then <code>null</code> is returned and the scanner's
* position is unchanged. This method may block waiting for input that
* matches the pattern.
*
* <p>Since this method continues to search through the input looking
* for the specified pattern, it may buffer all of the input searching for
* the desired token if no line separators are present.
*
* @param pattern the pattern to scan for
* @return the text that matched the specified pattern
* @throws IllegalStateException if this scanner is closed
*/
public
String findInLine(
Pattern pattern) {
ensureOpen();
if (
pattern == null)
throw new
NullPointerException();
clearCaches();
// Expand buffer to include the next newline or end of input
int
endPosition = 0;
saveState();
while (true) {
String token =
findPatternInBuffer(
separatorPattern(), 0);
if (
token != null) {
endPosition =
matcher.
start();
break; // up to next newline
}
if (
needInput) {
readInput();
} else {
endPosition =
buf.
limit();
break; // up to end of input
}
}
revertState();
int
horizonForLine =
endPosition -
position;
// If there is nothing between the current pos and the next
// newline simply return null, invoking findWithinHorizon
// with "horizon=0" will scan beyond the line bound.
if (
horizonForLine == 0)
return null;
// Search for the pattern
return
findWithinHorizon(
pattern,
horizonForLine);
}
/**
* Attempts to find the next occurrence of a pattern constructed from the
* specified string, ignoring delimiters.
*
* <p>An invocation of this method of the form
* <tt>findWithinHorizon(pattern)</tt> behaves in exactly the same way as
* the invocation
* <tt>findWithinHorizon(Pattern.compile(pattern, horizon))</tt>.
*
* @param pattern a string specifying the pattern to search for
* @param horizon the search horizon
* @return the text that matched the specified pattern
* @throws IllegalStateException if this scanner is closed
* @throws IllegalArgumentException if horizon is negative
*/
public
String findWithinHorizon(
String pattern, int
horizon) {
return
findWithinHorizon(
patternCache.
forName(
pattern),
horizon);
}
/**
* Attempts to find the next occurrence of the specified pattern.
*
* <p>This method searches through the input up to the specified
* search horizon, ignoring delimiters. If the pattern is found the
* scanner advances past the input that matched and returns the string
* that matched the pattern. If no such pattern is detected then the
* null is returned and the scanner's position remains unchanged. This
* method may block waiting for input that matches the pattern.
*
* <p>A scanner will never search more than <code>horizon</code> code
* points beyond its current position. Note that a match may be clipped
* by the horizon; that is, an arbitrary match result may have been
* different if the horizon had been larger. The scanner treats the
* horizon as a transparent, non-anchoring bound (see {@link
* Matcher#useTransparentBounds} and {@link Matcher#useAnchoringBounds}).
*
* <p>If horizon is <code>0</code>, then the horizon is ignored and
* this method continues to search through the input looking for the
* specified pattern without bound. In this case it may buffer all of
* the input searching for the pattern.
*
* <p>If horizon is negative, then an IllegalArgumentException is
* thrown.
*
* @param pattern the pattern to scan for
* @param horizon the search horizon
* @return the text that matched the specified pattern
* @throws IllegalStateException if this scanner is closed
* @throws IllegalArgumentException if horizon is negative
*/
public
String findWithinHorizon(
Pattern pattern, int
horizon) {
ensureOpen();
if (
pattern == null)
throw new
NullPointerException();
if (
horizon < 0)
throw new
IllegalArgumentException("horizon < 0");
clearCaches();
// Search for the pattern
while (true) {
String token =
findPatternInBuffer(
pattern,
horizon);
if (
token != null) {
matchValid = true;
return
token;
}
if (
needInput)
readInput();
else
break; // up to end of input
}
return null;
}
/**
* Skips input that matches the specified pattern, ignoring delimiters.
* This method will skip input if an anchored match of the specified
* pattern succeeds.
*
* <p>If a match to the specified pattern is not found at the
* current position, then no input is skipped and a
* <tt>NoSuchElementException</tt> is thrown.
*
* <p>Since this method seeks to match the specified pattern starting at
* the scanner's current position, patterns that can match a lot of
* input (".*", for example) may cause the scanner to buffer a large
* amount of input.
*
* <p>Note that it is possible to skip something without risking a
* <code>NoSuchElementException</code> by using a pattern that can
* match nothing, e.g., <code>sc.skip("[ \t]*")</code>.
*
* @param pattern a string specifying the pattern to skip over
* @return this scanner
* @throws NoSuchElementException if the specified pattern is not found
* @throws IllegalStateException if this scanner is closed
*/
public
Scanner skip(
Pattern pattern) {
ensureOpen();
if (
pattern == null)
throw new
NullPointerException();
clearCaches();
// Search for the pattern
while (true) {
String token =
matchPatternInBuffer(
pattern);
if (
token != null) {
matchValid = true;
position =
matcher.
end();
return this;
}
if (
needInput)
readInput();
else
throw new
NoSuchElementException();
}
}
/**
* Skips input that matches a pattern constructed from the specified
* string.
*
* <p> An invocation of this method of the form <tt>skip(pattern)</tt>
* behaves in exactly the same way as the invocation
* <tt>skip(Pattern.compile(pattern))</tt>.
*
* @param pattern a string specifying the pattern to skip over
* @return this scanner
* @throws IllegalStateException if this scanner is closed
*/
public
Scanner skip(
String pattern) {
return
skip(
patternCache.
forName(
pattern));
}
// Convenience methods for scanning primitives
/**
* Returns true if the next token in this scanner's input can be
* interpreted as a boolean value using a case insensitive pattern
* created from the string "true|false". The scanner does not
* advance past the input that matched.
*
* @return true if and only if this scanner's next token is a valid
* boolean value
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextBoolean() {
return
hasNext(
boolPattern());
}
/**
* Scans the next token of the input into a boolean value and returns
* that value. This method will throw <code>InputMismatchException</code>
* if the next token cannot be translated into a valid boolean value.
* If the match is successful, the scanner advances past the input that
* matched.
*
* @return the boolean scanned from the input
* @throws InputMismatchException if the next token is not a valid boolean
* @throws NoSuchElementException if input is exhausted
* @throws IllegalStateException if this scanner is closed
*/
public boolean
nextBoolean() {
clearCaches();
return
Boolean.
parseBoolean(
next(
boolPattern()));
}
/**
* Returns true if the next token in this scanner's input can be
* interpreted as a byte value in the default radix using the
* {@link #nextByte} method. The scanner does not advance past any input.
*
* @return true if and only if this scanner's next token is a valid
* byte value
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextByte() {
return
hasNextByte(
defaultRadix);
}
/**
* Returns true if the next token in this scanner's input can be
* interpreted as a byte value in the specified radix using the
* {@link #nextByte} method. The scanner does not advance past any input.
*
* @param radix the radix used to interpret the token as a byte value
* @return true if and only if this scanner's next token is a valid
* byte value
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextByte(int
radix) {
setRadix(
radix);
boolean
result =
hasNext(
integerPattern());
if (
result) { // Cache it
try {
String s = (
matcher.
group(
SIMPLE_GROUP_INDEX) == null) ?
processIntegerToken(
hasNextResult) :
hasNextResult;
typeCache =
Byte.
parseByte(
s,
radix);
} catch (
NumberFormatException nfe) {
result = false;
}
}
return
result;
}
/**
* Scans the next token of the input as a <tt>byte</tt>.
*
* <p> An invocation of this method of the form
* <tt>nextByte()</tt> behaves in exactly the same way as the
* invocation <tt>nextByte(radix)</tt>, where <code>radix</code>
* is the default radix of this scanner.
*
* @return the <tt>byte</tt> scanned from the input
* @throws InputMismatchException
* if the next token does not match the <i>Integer</i>
* regular expression, or is out of range
* @throws NoSuchElementException if input is exhausted
* @throws IllegalStateException if this scanner is closed
*/
public byte
nextByte() {
return
nextByte(
defaultRadix);
}
/**
* Scans the next token of the input as a <tt>byte</tt>.
* This method will throw <code>InputMismatchException</code>
* if the next token cannot be translated into a valid byte value as
* described below. If the translation is successful, the scanner advances
* past the input that matched.
*
* <p> If the next token matches the <a
* href="#Integer-regex"><i>Integer</i></a> regular expression defined
* above then the token is converted into a <tt>byte</tt> value as if by
* removing all locale specific prefixes, group separators, and locale
* specific suffixes, then mapping non-ASCII digits into ASCII
* digits via {@link Character#digit Character.digit}, prepending a
* negative sign (-) if the locale specific negative prefixes and suffixes
* were present, and passing the resulting string to
* {@link Byte#parseByte(String, int) Byte.parseByte} with the
* specified radix.
*
* @param radix the radix used to interpret the token as a byte value
* @return the <tt>byte</tt> scanned from the input
* @throws InputMismatchException
* if the next token does not match the <i>Integer</i>
* regular expression, or is out of range
* @throws NoSuchElementException if input is exhausted
* @throws IllegalStateException if this scanner is closed
*/
public byte
nextByte(int
radix) {
// Check cached result
if ((
typeCache != null) && (
typeCache instanceof
Byte)
&& this.
radix ==
radix) {
byte
val = ((
Byte)
typeCache).
byteValue();
useTypeCache();
return
val;
}
setRadix(
radix);
clearCaches();
// Search for next byte
try {
String s =
next(
integerPattern());
if (
matcher.
group(
SIMPLE_GROUP_INDEX) == null)
s =
processIntegerToken(
s);
return
Byte.
parseByte(
s,
radix);
} catch (
NumberFormatException nfe) {
position =
matcher.
start(); // don't skip bad token
throw new
InputMismatchException(
nfe.
getMessage());
}
}
/**
* Returns true if the next token in this scanner's input can be
* interpreted as a short value in the default radix using the
* {@link #nextShort} method. The scanner does not advance past any input.
*
* @return true if and only if this scanner's next token is a valid
* short value in the default radix
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextShort() {
return
hasNextShort(
defaultRadix);
}
/**
* Returns true if the next token in this scanner's input can be
* interpreted as a short value in the specified radix using the
* {@link #nextShort} method. The scanner does not advance past any input.
*
* @param radix the radix used to interpret the token as a short value
* @return true if and only if this scanner's next token is a valid
* short value in the specified radix
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextShort(int
radix) {
setRadix(
radix);
boolean
result =
hasNext(
integerPattern());
if (
result) { // Cache it
try {
String s = (
matcher.
group(
SIMPLE_GROUP_INDEX) == null) ?
processIntegerToken(
hasNextResult) :
hasNextResult;
typeCache =
Short.
parseShort(
s,
radix);
} catch (
NumberFormatException nfe) {
result = false;
}
}
return
result;
}
/**
* Scans the next token of the input as a <tt>short</tt>.
*
* <p> An invocation of this method of the form
* <tt>nextShort()</tt> behaves in exactly the same way as the
* invocation <tt>nextShort(radix)</tt>, where <code>radix</code>
* is the default radix of this scanner.
*
* @return the <tt>short</tt> scanned from the input
* @throws InputMismatchException
* if the next token does not match the <i>Integer</i>
* regular expression, or is out of range
* @throws NoSuchElementException if input is exhausted
* @throws IllegalStateException if this scanner is closed
*/
public short
nextShort() {
return
nextShort(
defaultRadix);
}
/**
* Scans the next token of the input as a <tt>short</tt>.
* This method will throw <code>InputMismatchException</code>
* if the next token cannot be translated into a valid short value as
* described below. If the translation is successful, the scanner advances
* past the input that matched.
*
* <p> If the next token matches the <a
* href="#Integer-regex"><i>Integer</i></a> regular expression defined
* above then the token is converted into a <tt>short</tt> value as if by
* removing all locale specific prefixes, group separators, and locale
* specific suffixes, then mapping non-ASCII digits into ASCII
* digits via {@link Character#digit Character.digit}, prepending a
* negative sign (-) if the locale specific negative prefixes and suffixes
* were present, and passing the resulting string to
* {@link Short#parseShort(String, int) Short.parseShort} with the
* specified radix.
*
* @param radix the radix used to interpret the token as a short value
* @return the <tt>short</tt> scanned from the input
* @throws InputMismatchException
* if the next token does not match the <i>Integer</i>
* regular expression, or is out of range
* @throws NoSuchElementException if input is exhausted
* @throws IllegalStateException if this scanner is closed
*/
public short
nextShort(int
radix) {
// Check cached result
if ((
typeCache != null) && (
typeCache instanceof
Short)
&& this.
radix ==
radix) {
short
val = ((
Short)
typeCache).
shortValue();
useTypeCache();
return
val;
}
setRadix(
radix);
clearCaches();
// Search for next short
try {
String s =
next(
integerPattern());
if (
matcher.
group(
SIMPLE_GROUP_INDEX) == null)
s =
processIntegerToken(
s);
return
Short.
parseShort(
s,
radix);
} catch (
NumberFormatException nfe) {
position =
matcher.
start(); // don't skip bad token
throw new
InputMismatchException(
nfe.
getMessage());
}
}
/**
* Returns true if the next token in this scanner's input can be
* interpreted as an int value in the default radix using the
* {@link #nextInt} method. The scanner does not advance past any input.
*
* @return true if and only if this scanner's next token is a valid
* int value
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextInt() {
return
hasNextInt(
defaultRadix);
}
/**
* Returns true if the next token in this scanner's input can be
* interpreted as an int value in the specified radix using the
* {@link #nextInt} method. The scanner does not advance past any input.
*
* @param radix the radix used to interpret the token as an int value
* @return true if and only if this scanner's next token is a valid
* int value
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextInt(int
radix) {
setRadix(
radix);
boolean
result =
hasNext(
integerPattern());
if (
result) { // Cache it
try {
String s = (
matcher.
group(
SIMPLE_GROUP_INDEX) == null) ?
processIntegerToken(
hasNextResult) :
hasNextResult;
typeCache =
Integer.
parseInt(
s,
radix);
} catch (
NumberFormatException nfe) {
result = false;
}
}
return
result;
}
/**
* The integer token must be stripped of prefixes, group separators,
* and suffixes, non ascii digits must be converted into ascii digits
* before parse will accept it.
*/
private
String processIntegerToken(
String token) {
String result =
token.
replaceAll(""+
groupSeparator, "");
boolean
isNegative = false;
int
preLen =
negativePrefix.
length();
if ((
preLen > 0) &&
result.
startsWith(
negativePrefix)) {
isNegative = true;
result =
result.
substring(
preLen);
}
int
sufLen =
negativeSuffix.
length();
if ((
sufLen > 0) &&
result.
endsWith(
negativeSuffix)) {
isNegative = true;
result =
result.
substring(
result.
length() -
sufLen,
result.
length());
}
if (
isNegative)
result = "-" +
result;
return
result;
}
/**
* Scans the next token of the input as an <tt>int</tt>.
*
* <p> An invocation of this method of the form
* <tt>nextInt()</tt> behaves in exactly the same way as the
* invocation <tt>nextInt(radix)</tt>, where <code>radix</code>
* is the default radix of this scanner.
*
* @return the <tt>int</tt> scanned from the input
* @throws InputMismatchException
* if the next token does not match the <i>Integer</i>
* regular expression, or is out of range
* @throws NoSuchElementException if input is exhausted
* @throws IllegalStateException if this scanner is closed
*/
public int
nextInt() {
return
nextInt(
defaultRadix);
}
/**
* Scans the next token of the input as an <tt>int</tt>.
* This method will throw <code>InputMismatchException</code>
* if the next token cannot be translated into a valid int value as
* described below. If the translation is successful, the scanner advances
* past the input that matched.
*
* <p> If the next token matches the <a
* href="#Integer-regex"><i>Integer</i></a> regular expression defined
* above then the token is converted into an <tt>int</tt> value as if by
* removing all locale specific prefixes, group separators, and locale
* specific suffixes, then mapping non-ASCII digits into ASCII
* digits via {@link Character#digit Character.digit}, prepending a
* negative sign (-) if the locale specific negative prefixes and suffixes
* were present, and passing the resulting string to
* {@link Integer#parseInt(String, int) Integer.parseInt} with the
* specified radix.
*
* @param radix the radix used to interpret the token as an int value
* @return the <tt>int</tt> scanned from the input
* @throws InputMismatchException
* if the next token does not match the <i>Integer</i>
* regular expression, or is out of range
* @throws NoSuchElementException if input is exhausted
* @throws IllegalStateException if this scanner is closed
*/
public int
nextInt(int
radix) {
// Check cached result
if ((
typeCache != null) && (
typeCache instanceof
Integer)
&& this.
radix ==
radix) {
int
val = ((
Integer)
typeCache).
intValue();
useTypeCache();
return
val;
}
setRadix(
radix);
clearCaches();
// Search for next int
try {
String s =
next(
integerPattern());
if (
matcher.
group(
SIMPLE_GROUP_INDEX) == null)
s =
processIntegerToken(
s);
return
Integer.
parseInt(
s,
radix);
} catch (
NumberFormatException nfe) {
position =
matcher.
start(); // don't skip bad token
throw new
InputMismatchException(
nfe.
getMessage());
}
}
/**
* Returns true if the next token in this scanner's input can be
* interpreted as a long value in the default radix using the
* {@link #nextLong} method. The scanner does not advance past any input.
*
* @return true if and only if this scanner's next token is a valid
* long value
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextLong() {
return
hasNextLong(
defaultRadix);
}
/**
* Returns true if the next token in this scanner's input can be
* interpreted as a long value in the specified radix using the
* {@link #nextLong} method. The scanner does not advance past any input.
*
* @param radix the radix used to interpret the token as a long value
* @return true if and only if this scanner's next token is a valid
* long value
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextLong(int
radix) {
setRadix(
radix);
boolean
result =
hasNext(
integerPattern());
if (
result) { // Cache it
try {
String s = (
matcher.
group(
SIMPLE_GROUP_INDEX) == null) ?
processIntegerToken(
hasNextResult) :
hasNextResult;
typeCache =
Long.
parseLong(
s,
radix);
} catch (
NumberFormatException nfe) {
result = false;
}
}
return
result;
}
/**
* Scans the next token of the input as a <tt>long</tt>.
*
* <p> An invocation of this method of the form
* <tt>nextLong()</tt> behaves in exactly the same way as the
* invocation <tt>nextLong(radix)</tt>, where <code>radix</code>
* is the default radix of this scanner.
*
* @return the <tt>long</tt> scanned from the input
* @throws InputMismatchException
* if the next token does not match the <i>Integer</i>
* regular expression, or is out of range
* @throws NoSuchElementException if input is exhausted
* @throws IllegalStateException if this scanner is closed
*/
public long
nextLong() {
return
nextLong(
defaultRadix);
}
/**
* Scans the next token of the input as a <tt>long</tt>.
* This method will throw <code>InputMismatchException</code>
* if the next token cannot be translated into a valid long value as
* described below. If the translation is successful, the scanner advances
* past the input that matched.
*
* <p> If the next token matches the <a
* href="#Integer-regex"><i>Integer</i></a> regular expression defined
* above then the token is converted into a <tt>long</tt> value as if by
* removing all locale specific prefixes, group separators, and locale
* specific suffixes, then mapping non-ASCII digits into ASCII
* digits via {@link Character#digit Character.digit}, prepending a
* negative sign (-) if the locale specific negative prefixes and suffixes
* were present, and passing the resulting string to
* {@link Long#parseLong(String, int) Long.parseLong} with the
* specified radix.
*
* @param radix the radix used to interpret the token as an int value
* @return the <tt>long</tt> scanned from the input
* @throws InputMismatchException
* if the next token does not match the <i>Integer</i>
* regular expression, or is out of range
* @throws NoSuchElementException if input is exhausted
* @throws IllegalStateException if this scanner is closed
*/
public long
nextLong(int
radix) {
// Check cached result
if ((
typeCache != null) && (
typeCache instanceof
Long)
&& this.
radix ==
radix) {
long
val = ((
Long)
typeCache).
longValue();
useTypeCache();
return
val;
}
setRadix(
radix);
clearCaches();
try {
String s =
next(
integerPattern());
if (
matcher.
group(
SIMPLE_GROUP_INDEX) == null)
s =
processIntegerToken(
s);
return
Long.
parseLong(
s,
radix);
} catch (
NumberFormatException nfe) {
position =
matcher.
start(); // don't skip bad token
throw new
InputMismatchException(
nfe.
getMessage());
}
}
/**
* The float token must be stripped of prefixes, group separators,
* and suffixes, non ascii digits must be converted into ascii digits
* before parseFloat will accept it.
*
* If there are non-ascii digits in the token these digits must
* be processed before the token is passed to parseFloat.
*/
private
String processFloatToken(
String token) {
String result =
token.
replaceAll(
groupSeparator, "");
if (!
decimalSeparator.
equals("\\."))
result =
result.
replaceAll(
decimalSeparator, ".");
boolean
isNegative = false;
int
preLen =
negativePrefix.
length();
if ((
preLen > 0) &&
result.
startsWith(
negativePrefix)) {
isNegative = true;
result =
result.
substring(
preLen);
}
int
sufLen =
negativeSuffix.
length();
if ((
sufLen > 0) &&
result.
endsWith(
negativeSuffix)) {
isNegative = true;
result =
result.
substring(
result.
length() -
sufLen,
result.
length());
}
if (
result.
equals(
nanString))
result = "NaN";
if (
result.
equals(
infinityString))
result = "Infinity";
if (
isNegative)
result = "-" +
result;
// Translate non-ASCII digits
Matcher m =
NON_ASCII_DIGIT.
matcher(
result);
if (
m.
find()) {
StringBuilder inASCII = new
StringBuilder();
for (int
i=0;
i<
result.
length();
i++) {
char
nextChar =
result.
charAt(
i);
if (
Character.
isDigit(
nextChar)) {
int
d =
Character.
digit(
nextChar, 10);
if (
d != -1)
inASCII.
append(
d);
else
inASCII.
append(
nextChar);
} else {
inASCII.
append(
nextChar);
}
}
result =
inASCII.
toString();
}
return
result;
}
/**
* Returns true if the next token in this scanner's input can be
* interpreted as a float value using the {@link #nextFloat}
* method. The scanner does not advance past any input.
*
* @return true if and only if this scanner's next token is a valid
* float value
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextFloat() {
setRadix(10);
boolean
result =
hasNext(
floatPattern());
if (
result) { // Cache it
try {
String s =
processFloatToken(
hasNextResult);
typeCache =
Float.
valueOf(
Float.
parseFloat(
s));
} catch (
NumberFormatException nfe) {
result = false;
}
}
return
result;
}
/**
* Scans the next token of the input as a <tt>float</tt>.
* This method will throw <code>InputMismatchException</code>
* if the next token cannot be translated into a valid float value as
* described below. If the translation is successful, the scanner advances
* past the input that matched.
*
* <p> If the next token matches the <a
* href="#Float-regex"><i>Float</i></a> regular expression defined above
* then the token is converted into a <tt>float</tt> value as if by
* removing all locale specific prefixes, group separators, and locale
* specific suffixes, then mapping non-ASCII digits into ASCII
* digits via {@link Character#digit Character.digit}, prepending a
* negative sign (-) if the locale specific negative prefixes and suffixes
* were present, and passing the resulting string to
* {@link Float#parseFloat Float.parseFloat}. If the token matches
* the localized NaN or infinity strings, then either "Nan" or "Infinity"
* is passed to {@link Float#parseFloat(String) Float.parseFloat} as
* appropriate.
*
* @return the <tt>float</tt> scanned from the input
* @throws InputMismatchException
* if the next token does not match the <i>Float</i>
* regular expression, or is out of range
* @throws NoSuchElementException if input is exhausted
* @throws IllegalStateException if this scanner is closed
*/
public float
nextFloat() {
// Check cached result
if ((
typeCache != null) && (
typeCache instanceof
Float)) {
float
val = ((
Float)
typeCache).
floatValue();
useTypeCache();
return
val;
}
setRadix(10);
clearCaches();
try {
return
Float.
parseFloat(
processFloatToken(
next(
floatPattern())));
} catch (
NumberFormatException nfe) {
position =
matcher.
start(); // don't skip bad token
throw new
InputMismatchException(
nfe.
getMessage());
}
}
/**
* Returns true if the next token in this scanner's input can be
* interpreted as a double value using the {@link #nextDouble}
* method. The scanner does not advance past any input.
*
* @return true if and only if this scanner's next token is a valid
* double value
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextDouble() {
setRadix(10);
boolean
result =
hasNext(
floatPattern());
if (
result) { // Cache it
try {
String s =
processFloatToken(
hasNextResult);
typeCache =
Double.
valueOf(
Double.
parseDouble(
s));
} catch (
NumberFormatException nfe) {
result = false;
}
}
return
result;
}
/**
* Scans the next token of the input as a <tt>double</tt>.
* This method will throw <code>InputMismatchException</code>
* if the next token cannot be translated into a valid double value.
* If the translation is successful, the scanner advances past the input
* that matched.
*
* <p> If the next token matches the <a
* href="#Float-regex"><i>Float</i></a> regular expression defined above
* then the token is converted into a <tt>double</tt> value as if by
* removing all locale specific prefixes, group separators, and locale
* specific suffixes, then mapping non-ASCII digits into ASCII
* digits via {@link Character#digit Character.digit}, prepending a
* negative sign (-) if the locale specific negative prefixes and suffixes
* were present, and passing the resulting string to
* {@link Double#parseDouble Double.parseDouble}. If the token matches
* the localized NaN or infinity strings, then either "Nan" or "Infinity"
* is passed to {@link Double#parseDouble(String) Double.parseDouble} as
* appropriate.
*
* @return the <tt>double</tt> scanned from the input
* @throws InputMismatchException
* if the next token does not match the <i>Float</i>
* regular expression, or is out of range
* @throws NoSuchElementException if the input is exhausted
* @throws IllegalStateException if this scanner is closed
*/
public double
nextDouble() {
// Check cached result
if ((
typeCache != null) && (
typeCache instanceof
Double)) {
double
val = ((
Double)
typeCache).
doubleValue();
useTypeCache();
return
val;
}
setRadix(10);
clearCaches();
// Search for next float
try {
return
Double.
parseDouble(
processFloatToken(
next(
floatPattern())));
} catch (
NumberFormatException nfe) {
position =
matcher.
start(); // don't skip bad token
throw new
InputMismatchException(
nfe.
getMessage());
}
}
// Convenience methods for scanning multi precision numbers
/**
* Returns true if the next token in this scanner's input can be
* interpreted as a <code>BigInteger</code> in the default radix using the
* {@link #nextBigInteger} method. The scanner does not advance past any
* input.
*
* @return true if and only if this scanner's next token is a valid
* <code>BigInteger</code>
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextBigInteger() {
return
hasNextBigInteger(
defaultRadix);
}
/**
* Returns true if the next token in this scanner's input can be
* interpreted as a <code>BigInteger</code> in the specified radix using
* the {@link #nextBigInteger} method. The scanner does not advance past
* any input.
*
* @param radix the radix used to interpret the token as an integer
* @return true if and only if this scanner's next token is a valid
* <code>BigInteger</code>
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextBigInteger(int
radix) {
setRadix(
radix);
boolean
result =
hasNext(
integerPattern());
if (
result) { // Cache it
try {
String s = (
matcher.
group(
SIMPLE_GROUP_INDEX) == null) ?
processIntegerToken(
hasNextResult) :
hasNextResult;
typeCache = new
BigInteger(
s,
radix);
} catch (
NumberFormatException nfe) {
result = false;
}
}
return
result;
}
/**
* Scans the next token of the input as a {@link java.math.BigInteger
* BigInteger}.
*
* <p> An invocation of this method of the form
* <tt>nextBigInteger()</tt> behaves in exactly the same way as the
* invocation <tt>nextBigInteger(radix)</tt>, where <code>radix</code>
* is the default radix of this scanner.
*
* @return the <tt>BigInteger</tt> scanned from the input
* @throws InputMismatchException
* if the next token does not match the <i>Integer</i>
* regular expression, or is out of range
* @throws NoSuchElementException if the input is exhausted
* @throws IllegalStateException if this scanner is closed
*/
public
BigInteger nextBigInteger() {
return
nextBigInteger(
defaultRadix);
}
/**
* Scans the next token of the input as a {@link java.math.BigInteger
* BigInteger}.
*
* <p> If the next token matches the <a
* href="#Integer-regex"><i>Integer</i></a> regular expression defined
* above then the token is converted into a <tt>BigInteger</tt> value as if
* by removing all group separators, mapping non-ASCII digits into ASCII
* digits via the {@link Character#digit Character.digit}, and passing the
* resulting string to the {@link
* java.math.BigInteger#BigInteger(java.lang.String)
* BigInteger(String, int)} constructor with the specified radix.
*
* @param radix the radix used to interpret the token
* @return the <tt>BigInteger</tt> scanned from the input
* @throws InputMismatchException
* if the next token does not match the <i>Integer</i>
* regular expression, or is out of range
* @throws NoSuchElementException if the input is exhausted
* @throws IllegalStateException if this scanner is closed
*/
public
BigInteger nextBigInteger(int
radix) {
// Check cached result
if ((
typeCache != null) && (
typeCache instanceof
BigInteger)
&& this.
radix ==
radix) {
BigInteger val = (
BigInteger)
typeCache;
useTypeCache();
return
val;
}
setRadix(
radix);
clearCaches();
// Search for next int
try {
String s =
next(
integerPattern());
if (
matcher.
group(
SIMPLE_GROUP_INDEX) == null)
s =
processIntegerToken(
s);
return new
BigInteger(
s,
radix);
} catch (
NumberFormatException nfe) {
position =
matcher.
start(); // don't skip bad token
throw new
InputMismatchException(
nfe.
getMessage());
}
}
/**
* Returns true if the next token in this scanner's input can be
* interpreted as a <code>BigDecimal</code> using the
* {@link #nextBigDecimal} method. The scanner does not advance past any
* input.
*
* @return true if and only if this scanner's next token is a valid
* <code>BigDecimal</code>
* @throws IllegalStateException if this scanner is closed
*/
public boolean
hasNextBigDecimal() {
setRadix(10);
boolean
result =
hasNext(
decimalPattern());
if (
result) { // Cache it
try {
String s =
processFloatToken(
hasNextResult);
typeCache = new
BigDecimal(
s);
} catch (
NumberFormatException nfe) {
result = false;
}
}
return
result;
}
/**
* Scans the next token of the input as a {@link java.math.BigDecimal
* BigDecimal}.
*
* <p> If the next token matches the <a
* href="#Decimal-regex"><i>Decimal</i></a> regular expression defined
* above then the token is converted into a <tt>BigDecimal</tt> value as if
* by removing all group separators, mapping non-ASCII digits into ASCII
* digits via the {@link Character#digit Character.digit}, and passing the
* resulting string to the {@link
* java.math.BigDecimal#BigDecimal(java.lang.String) BigDecimal(String)}
* constructor.
*
* @return the <tt>BigDecimal</tt> scanned from the input
* @throws InputMismatchException
* if the next token does not match the <i>Decimal</i>
* regular expression, or is out of range
* @throws NoSuchElementException if the input is exhausted
* @throws IllegalStateException if this scanner is closed
*/
public
BigDecimal nextBigDecimal() {
// Check cached result
if ((
typeCache != null) && (
typeCache instanceof
BigDecimal)) {
BigDecimal val = (
BigDecimal)
typeCache;
useTypeCache();
return
val;
}
setRadix(10);
clearCaches();
// Search for next float
try {
String s =
processFloatToken(
next(
decimalPattern()));
return new
BigDecimal(
s);
} catch (
NumberFormatException nfe) {
position =
matcher.
start(); // don't skip bad token
throw new
InputMismatchException(
nfe.
getMessage());
}
}
/**
* Resets this scanner.
*
* <p> Resetting a scanner discards all of its explicit state
* information which may have been changed by invocations of {@link
* #useDelimiter}, {@link #useLocale}, or {@link #useRadix}.
*
* <p> An invocation of this method of the form
* <tt>scanner.reset()</tt> behaves in exactly the same way as the
* invocation
*
* <blockquote><pre>{@code
* scanner.useDelimiter("\\p{javaWhitespace}+")
* .useLocale(Locale.getDefault(Locale.Category.FORMAT))
* .useRadix(10);
* }</pre></blockquote>
*
* @return this scanner
*
* @since 1.6
*/
public
Scanner reset() {
delimPattern =
WHITESPACE_PATTERN;
useLocale(
Locale.
getDefault(
Locale.
Category.
FORMAT));
useRadix(10);
clearCaches();
return this;
}
}