Java tutorial
/* * 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 {@code ImageOutputStream} that writes its * output directly to a {@code File} or * {@code RandomAccessFile}. * */ public class FileImageOutputStream extends ImageOutputStreamImpl { 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 FileImageOutputStream} that will write * to a given {@code File}. * * @param f a {@code File} to write to. * * @exception IllegalArgumentException if {@code f} is * {@code null}. * @exception SecurityException if a security manager exists * and does not allow write access to the file. * @exception FileNotFoundException if {@code f} does not denote * a regular file or it cannot be opened for reading and writing for any * other reason. * @exception IOException if an I/O error occurs. */ public FileImageOutputStream(File f) throws FileNotFoundException, IOException { this(f == null ? null : new RandomAccessFile(f, "rw")); } /** * Constructs a {@code FileImageOutputStream} that will write * to a given {@code RandomAccessFile}. * * @param raf a {@code RandomAccessFile} to write to. * * @exception IllegalArgumentException if {@code raf} is * {@code null}. */ public FileImageOutputStream(RandomAccessFile raf) { if (raf == null) { throw new IllegalArgumentException("raf == null!"); } this.raf = raf; disposerRecord = new CloseableDisposerRecord(raf); if (getClass() == FileImageOutputStream.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; } public void write(int b) throws IOException { flushBits(); // this will call checkClosed() for us raf.write(b); ++streamPos; } public void write(byte[] b, int off, int len) throws IOException { flushBits(); // this will call checkClosed() for us raf.write(b, off, len); streamPos += len; } public long length() { try { checkClosed(); return raf.length(); } catch (IOException e) { return -1L; } } /** * Sets the current stream position and resets the bit offset to * 0. It is legal to seeking past the end of the file; an * {@code EOFException} will be thrown only if a read is * performed. The file length will not be increased until a write * is performed. * * @exception IndexOutOfBoundsException if {@code pos} is smaller * than the flushed position. * @exception IOException if any other I/O error occurs. */ 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 {@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 } }