/*
* Copyright (c) 1996, 2005, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*/
package java.io;
import java.util.
Arrays;
/**
* This class implements a character buffer that can be used as an Writer.
* The buffer automatically grows when data is written to the stream. The data
* can be retrieved using toCharArray() and toString().
* <P>
* Note: Invoking close() on this class has no effect, and methods
* of this class can be called after the stream has closed
* without generating an IOException.
*
* @author Herb Jellinek
* @since JDK1.1
*/
public
class
CharArrayWriter extends
Writer {
/**
* The buffer where data is stored.
*/
protected char
buf[];
/**
* The number of chars in the buffer.
*/
protected int
count;
/**
* Creates a new CharArrayWriter.
*/
public
CharArrayWriter() {
this(32);
}
/**
* Creates a new CharArrayWriter with the specified initial size.
*
* @param initialSize an int specifying the initial buffer size.
* @exception IllegalArgumentException if initialSize is negative
*/
public
CharArrayWriter(int
initialSize) {
if (
initialSize < 0) {
throw new
IllegalArgumentException("Negative initial size: "
+
initialSize);
}
buf = new char[
initialSize];
}
/**
* Writes a character to the buffer.
*/
public void
write(int
c) {
synchronized (
lock) {
int
newcount =
count + 1;
if (
newcount >
buf.length) {
buf =
Arrays.
copyOf(
buf,
Math.
max(
buf.length << 1,
newcount));
}
buf[
count] = (char)
c;
count =
newcount;
}
}
/**
* Writes characters to the buffer.
* @param c the data to be written
* @param off the start offset in the data
* @param len the number of chars that are written
*/
public void
write(char
c[], int
off, int
len) {
if ((
off < 0) || (
off >
c.length) || (
len < 0) ||
((
off +
len) >
c.length) || ((
off +
len) < 0)) {
throw new
IndexOutOfBoundsException();
} else if (
len == 0) {
return;
}
synchronized (
lock) {
int
newcount =
count +
len;
if (
newcount >
buf.length) {
buf =
Arrays.
copyOf(
buf,
Math.
max(
buf.length << 1,
newcount));
}
System.
arraycopy(
c,
off,
buf,
count,
len);
count =
newcount;
}
}
/**
* Write a portion of a string to the buffer.
* @param str String to be written from
* @param off Offset from which to start reading characters
* @param len Number of characters to be written
*/
public void
write(
String str, int
off, int
len) {
synchronized (
lock) {
int
newcount =
count +
len;
if (
newcount >
buf.length) {
buf =
Arrays.
copyOf(
buf,
Math.
max(
buf.length << 1,
newcount));
}
str.
getChars(
off,
off +
len,
buf,
count);
count =
newcount;
}
}
/**
* Writes the contents of the buffer to another character stream.
*
* @param out the output stream to write to
* @throws IOException If an I/O error occurs.
*/
public void
writeTo(
Writer out) throws
IOException {
synchronized (
lock) {
out.
write(
buf, 0,
count);
}
}
/**
* Appends the specified character sequence to this writer.
*
* <p> An invocation of this method of the form <tt>out.append(csq)</tt>
* behaves in exactly the same way as the invocation
*
* <pre>
* out.write(csq.toString()) </pre>
*
* <p> Depending on the specification of <tt>toString</tt> for the
* character sequence <tt>csq</tt>, the entire sequence may not be
* appended. For instance, invoking the <tt>toString</tt> method of a
* character buffer will return a subsequence whose content depends upon
* the buffer's position and limit.
*
* @param csq
* The character sequence to append. If <tt>csq</tt> is
* <tt>null</tt>, then the four characters <tt>"null"</tt> are
* appended to this writer.
*
* @return This writer
*
* @since 1.5
*/
public
CharArrayWriter append(
CharSequence csq) {
String s = (
csq == null ? "null" :
csq.
toString());
write(
s, 0,
s.
length());
return this;
}
/**
* Appends a subsequence of the specified character sequence to this writer.
*
* <p> An invocation of this method of the form <tt>out.append(csq, start,
* end)</tt> when <tt>csq</tt> is not <tt>null</tt>, behaves in
* exactly the same way as the invocation
*
* <pre>
* out.write(csq.subSequence(start, end).toString()) </pre>
*
* @param csq
* The character sequence from which a subsequence will be
* appended. If <tt>csq</tt> is <tt>null</tt>, then characters
* will be appended as if <tt>csq</tt> contained the four
* characters <tt>"null"</tt>.
*
* @param start
* The index of the first character in the subsequence
*
* @param end
* The index of the character following the last character in the
* subsequence
*
* @return This writer
*
* @throws IndexOutOfBoundsException
* If <tt>start</tt> or <tt>end</tt> are negative, <tt>start</tt>
* is greater than <tt>end</tt>, or <tt>end</tt> is greater than
* <tt>csq.length()</tt>
*
* @since 1.5
*/
public
CharArrayWriter append(
CharSequence csq, int
start, int
end) {
String s = (
csq == null ? "null" :
csq).
subSequence(
start,
end).
toString();
write(
s, 0,
s.
length());
return this;
}
/**
* Appends the specified character to this writer.
*
* <p> An invocation of this method of the form <tt>out.append(c)</tt>
* behaves in exactly the same way as the invocation
*
* <pre>
* out.write(c) </pre>
*
* @param c
* The 16-bit character to append
*
* @return This writer
*
* @since 1.5
*/
public
CharArrayWriter append(char
c) {
write(
c);
return this;
}
/**
* Resets the buffer so that you can use it again without
* throwing away the already allocated buffer.
*/
public void
reset() {
count = 0;
}
/**
* Returns a copy of the input data.
*
* @return an array of chars copied from the input data.
*/
public char
toCharArray()[] {
synchronized (
lock) {
return
Arrays.
copyOf(
buf,
count);
}
}
/**
* Returns the current size of the buffer.
*
* @return an int representing the current size of the buffer.
*/
public int
size() {
return
count;
}
/**
* Converts input data to a string.
* @return the string.
*/
public
String toString() {
synchronized (
lock) {
return new
String(
buf, 0,
count);
}
}
/**
* Flush the stream.
*/
public void
flush() { }
/**
* Close the stream. This method does not release the buffer, since its
* contents might still be required. Note: Invoking this method in this class
* will have no effect.
*/
public void
close() { }
}