bundles/org.eclipse.osgi/defaultAdaptor/src/org/eclipse/osgi/framework/internal/reliablefile/ReliableFileOutputStream.java

/*******************************************************************************
 * Copyright (c) 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.osgi.framework.internal.reliablefile;

import java.io.*;

/**
 * A ReliableFile FileOutputStream replacement class.
 * This class can be used just like FileOutputStream. The class
 * is in partnership with ReliableFileInputStream to avoid losing
 * file data by using multiple files.
 *
 * @see			ReliableFileInputStream
 */
public class ReliableFileOutputStream extends FilterOutputStream {
	/**
	 * ReliableFile object for the file.
	 */
	private ReliableFile reliable;

	/**
	 * Constructs a new ReliableFileOutputStream on the File <code>file</code>.  If the
	 * file exists, it is written over.  See the constructor which can append to
	 * the file if so desired.
	 *
	 * @param		file		the File on which to stream reads.
	 * @exception 	java.io.IOException If an error occurs opening the file.
	 */
	public ReliableFileOutputStream(File file) throws IOException {
		this(ReliableFile.getReliableFile(file), false);
	}

	/**
	 * Constructs a new ReliableFileOutputStream on the File <code>file</code>.
	 *
	 * @param		file		the File on which to stream reads.
	 * @param		append		a boolean indicating whether or not to append to an existing file.
	 * @exception 	java.io.IOException If an error occurs opening the file.
	 */
	public ReliableFileOutputStream(File file, boolean append) throws IOException {
		this(ReliableFile.getReliableFile(file), append);
	}

	/**
	 * Constructs a new ReliableFileOutputStream on the file named <code>name</code>. If
	 * the file exists, it is written over.  See the constructor which can append to
	 * the file if so desired.
	 * The <code>name</code> may be absolute or relative
	 * to the System property <code>"user.dir"</code>.
	 *
	 * @param		name	the file on which to stream writes.
	 * @exception 	java.io.IOException If an error occurs opening the file.
	 */
	public ReliableFileOutputStream(String name) throws IOException {
		this(ReliableFile.getReliableFile(name), false);
	}

	/**
	 * Constructs a new ReliableFileOutputStream on the file named <code>name</code>.
	 * The <code>name</code> may be absolute or relative
	 * to the System property <code>"user.dir"</code>.
	 *
	 * @param		name	the file on which to stream writes.
	 * @param		append		a boolean indicating whether or not to append to an existing file.
	 * @exception 	java.io.IOException If an error occurs opening the file.
	 */
	public ReliableFileOutputStream(String name, boolean append) throws IOException {
		this(ReliableFile.getReliableFile(name), append);
	}

	/**
	 * Private constructor used by other constructors.
	 *
	 * @param		reliable		the ReliableFile on which to read.
	 * @param		append		a boolean indicating whether or not to append to an existing file.
	 * @exception 	java.io.IOException If an error occurs opening the file.
	 */
	private ReliableFileOutputStream(ReliableFile reliable, boolean append) throws IOException {
		super(reliable.getOutputStream(append));

		this.reliable = reliable;
	}

	/**
	 * Closes this output stream and releases any system resources
	 * associated with this stream. The general contract of <code>close</code>
	 * is that it closes the output stream. A closed stream cannot perform
	 * output operations and cannot be reopened.
	 *
	 * @exception 	java.io.IOException If an error occurs closing the file.
	 */
	public synchronized void close() throws IOException {
		if (reliable != null) {
			try {
				super.close();
			} finally {
				reliable.closeOutputFile();
				reliable = null;
			}
		}
	}

	/**
	 * Call close to finalize the underlying ReliableFile.
	 */
	//TODO finalizers considered harmful! (bug 56856)	
	protected void finalize() throws IOException {
		close();
	}

	/**
	 * Override default FilterOutputStream method.
	 */
	public void write(byte b[], int off, int len) throws IOException {
		out.write(b, off, len);
	}
}