/*
* Copyright (c) 2000, 2007, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*/
package javax.imageio.stream;
import java.io.
File;
import java.io.
FileNotFoundException;
import java.io.
IOException;
import java.io.
RandomAccessFile;
import com.sun.imageio.stream.
CloseableDisposerRecord;
import com.sun.imageio.stream.
StreamFinalizer;
import sun.java2d.
Disposer;
/**
* An implementation of <code>ImageInputStream</code> that gets its
* input from a <code>File</code> or <code>RandomAccessFile</code>.
* The file contents are assumed to be stable during the lifetime of
* the object.
*
*/
public class
FileImageInputStream extends
ImageInputStreamImpl {
private
RandomAccessFile raf;
/** The referent to be registered with the Disposer. */
private final
Object disposerReferent;
/** The DisposerRecord that closes the underlying RandomAccessFile. */
private final
CloseableDisposerRecord disposerRecord;
/**
* Constructs a <code>FileImageInputStream</code> that will read
* from a given <code>File</code>.
*
* <p> The file contents must not change between the time this
* object is constructed and the time of the last call to a read
* method.
*
* @param f a <code>File</code> to read from.
*
* @exception IllegalArgumentException if <code>f</code> is
* <code>null</code>.
* @exception SecurityException if a security manager exists
* and does not allow read access to the file.
* @exception FileNotFoundException if <code>f</code> is a
* directory or cannot be opened for reading for any other reason.
* @exception IOException if an I/O error occurs.
*/
public
FileImageInputStream(
File f)
throws
FileNotFoundException,
IOException {
this(
f == null ? null : new
RandomAccessFile(
f, "r"));
}
/**
* Constructs a <code>FileImageInputStream</code> that will read
* from a given <code>RandomAccessFile</code>.
*
* <p> The file contents must not change between the time this
* object is constructed and the time of the last call to a read
* method.
*
* @param raf a <code>RandomAccessFile</code> to read from.
*
* @exception IllegalArgumentException if <code>raf</code> is
* <code>null</code>.
*/
public
FileImageInputStream(
RandomAccessFile raf) {
if (
raf == null) {
throw new
IllegalArgumentException("raf == null!");
}
this.
raf =
raf;
disposerRecord = new
CloseableDisposerRecord(
raf);
if (
getClass() ==
FileImageInputStream.class) {
disposerReferent = new
Object();
Disposer.
addRecord(
disposerReferent,
disposerRecord);
} else {
disposerReferent = new
StreamFinalizer(this);
}
}
public int
read() throws
IOException {
checkClosed();
bitOffset = 0;
int
val =
raf.
read();
if (
val != -1) {
++
streamPos;
}
return
val;
}
public int
read(byte[]
b, int
off, int
len) throws
IOException {
checkClosed();
bitOffset = 0;
int
nbytes =
raf.
read(
b,
off,
len);
if (
nbytes != -1) {
streamPos +=
nbytes;
}
return
nbytes;
}
/**
* Returns the length of the underlying file, or <code>-1</code>
* if it is unknown.
*
* @return the file length as a <code>long</code>, or
* <code>-1</code>.
*/
public long
length() {
try {
checkClosed();
return
raf.
length();
} catch (
IOException e) {
return -1L;
}
}
public void
seek(long
pos) throws
IOException {
checkClosed();
if (
pos <
flushedPos) {
throw new
IndexOutOfBoundsException("pos < flushedPos!");
}
bitOffset = 0;
raf.
seek(
pos);
streamPos =
raf.
getFilePointer();
}
public void
close() throws
IOException {
super.close();
disposerRecord.
dispose(); // this closes the RandomAccessFile
raf = null;
}
/**
* {@inheritDoc}
*/
protected void
finalize() throws
Throwable {
// Empty finalizer: for performance reasons we instead use the
// Disposer mechanism for ensuring that the underlying
// RandomAccessFile is closed prior to garbage collection
}
}