https://openjdk.java.net/ 
/*
 * Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

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 ImageInputStream that gets its input from a File or RandomAccessFile. The file contents are assumed to be stable during the lifetime of the object. 
/**
 * An implementation of {@code ImageInputStream} that gets its
 * input from a {@code File} or {@code RandomAccessFile}.
 * 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. 
/** The referent to be registered with the Disposer. */
    private final Object disposerReferent;

    
The DisposerRecord that closes the underlying RandomAccessFile. 
/** The DisposerRecord that closes the underlying RandomAccessFile. */
    private final CloseableDisposerRecord disposerRecord;

    
Constructs a FileImageInputStream that will read from a given File. 
 The file contents must not change between the time this
object is constructed and the time of the last call to a read
method.

Params:
  • f – a File to read from.
Throws:
/**
     * Constructs a {@code FileImageInputStream} that will read
     * from a given {@code File}.
     *
     * <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} to read from.
     *
     * @exception IllegalArgumentException if {@code f} is
     * {@code null}.
     * @exception SecurityException if a security manager exists
     * and does not allow read access to the file.
     * @exception FileNotFoundException if {@code f} 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 FileImageInputStream that will read from a given RandomAccessFile. 
 The file contents must not change between the time this
object is constructed and the time of the last call to a read
method.

Params:
  • raf – a RandomAccessFile to read from.
Throws:
/**
     * Constructs a {@code FileImageInputStream} that will read
     * from a given {@code RandomAccessFile}.
     *
     * <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} to read from.
     *
     * @exception IllegalArgumentException if {@code raf} is
     * {@code null}.
     */
    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 -1 if it is unknown. 
Returns:the file length as a long, or -1.
/**
     * Returns the length of the underlying file, or {@code -1}
     * if it is unknown.
     *
     * @return the file length as a {@code long}, or
     * {@code -1}.
     */
    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}

Deprecated:The finalize method has been deprecated. Subclasses that override finalize in order to perform cleanup should be modified to use alternative cleanup mechanisms and to remove the overriding finalize method. When overriding the finalize method, its implementation must explicitly ensure that super.finalize() is invoked as described in Object.finalize. See the specification for Object.finalize() for further information about migration options.
/**
     * {@inheritDoc}
     *
     * @deprecated The {@code finalize} method has been deprecated.
     *     Subclasses that override {@code finalize} in order to perform cleanup
     *     should be modified to use alternative cleanup mechanisms and
     *     to remove the overriding {@code finalize} method.
     *     When overriding the {@code finalize} method, its implementation must explicitly
     *     ensure that {@code super.finalize()} is invoked as described in {@link Object#finalize}.
     *     See the specification for {@link Object#finalize()} for further
     *     information about migration options.
     */
    @Deprecated(since="9")
    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
    }
}