org.eclipse.virgo.bundlor/src/main/java/org/eclipse/virgo/bundlor/util/FileCopyUtils.java

/*******************************************************************************
 * Copyright (c) 2008, 2010 VMware Inc.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   VMware Inc. - initial contribution
 *******************************************************************************/

package org.eclipse.virgo.bundlor.util;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;

import org.eclipse.virgo.bundlor.util.Assert;

/**
 * Simple utility methods for file and stream copying.
 * All copy methods use a block size of 4096 bytes,
 * and close all affected streams when done.
 *
 * <p>Mainly for use within the framework,
 * but also useful for application code.
 *
 * @author Juergen Hoeller
 * @since 06.10.2003
 */
public abstract class FileCopyUtils {

	public static final int BUFFER_SIZE = 4096;


	//---------------------------------------------------------------------
	// Copy methods for java.io.File
	//---------------------------------------------------------------------

	/**
	 * Copy the contents of the given input File to the given output File.
	 * @param in the file to copy from
	 * @param out the file to copy to
	 * @return the number of bytes copied
	 * @throws IOException in case of I/O errors
	 */
	public static int copy(File in, File out) throws IOException {
		Assert.notNull(in, "No input File specified");
		Assert.notNull(out, "No output File specified");
		return copy(new BufferedInputStream(new FileInputStream(in)),
		    new BufferedOutputStream(new FileOutputStream(out)));
	}

	/**
	 * Copy the contents of the given byte array to the given output File.
	 * @param in the byte array to copy from
	 * @param out the file to copy to
	 * @throws IOException in case of I/O errors
	 */
	public static void copy(byte[] in, File out) throws IOException {
		Assert.notNull(in, "No input byte array specified");
		Assert.notNull(out, "No output File specified");
		ByteArrayInputStream inStream = new ByteArrayInputStream(in);
		OutputStream outStream = new BufferedOutputStream(new FileOutputStream(out));
		copy(inStream, outStream);
	}

	/**
	 * Copy the contents of the given input File into a new byte array.
	 * @param in the file to copy from
	 * @return the new byte array that has been copied to
	 * @throws IOException in case of I/O errors
	 */
	public static byte[] copyToByteArray(File in) throws IOException {
		Assert.notNull(in, "No input File specified");
		return copyToByteArray(new BufferedInputStream(new FileInputStream(in)));
	}


	//---------------------------------------------------------------------
	// Copy methods for java.io.InputStream / java.io.OutputStream
	//---------------------------------------------------------------------

	/**
	 * Copy the contents of the given InputStream to the given OutputStream.
	 * Closes both streams when done.
	 * @param in the stream to copy from
	 * @param out the stream to copy to
	 * @return the number of bytes copied
	 * @throws IOException in case of I/O errors
	 */
	public static int copy(InputStream in, OutputStream out) throws IOException {
		Assert.notNull(in, "No InputStream specified");
		Assert.notNull(out, "No OutputStream specified");
		try {
			int byteCount = 0;
			byte[] buffer = new byte[BUFFER_SIZE];
			int bytesRead = -1;
			while ((bytesRead = in.read(buffer)) != -1) {
				out.write(buffer, 0, bytesRead);
				byteCount += bytesRead;
			}
			out.flush();
			return byteCount;
		}
		finally {
			try {
				in.close();
			}
			catch (IOException ex) {
			}
			try {
				out.close();
			}
			catch (IOException ex) {
			}
		}
	}

	/**
	 * Copy the contents of the given byte array to the given OutputStream.
	 * Closes the stream when done.
	 * @param in the byte array to copy from
	 * @param out the OutputStream to copy to
	 * @throws IOException in case of I/O errors
	 */
	public static void copy(byte[] in, OutputStream out) throws IOException {
		Assert.notNull(in, "No input byte array specified");
		Assert.notNull(out, "No OutputStream specified");
		try {
			out.write(in);
		}
		finally {
			try {
				out.close();
			}
			catch (IOException ex) {
			}
		}
	}

	/**
	 * Copy the contents of the given InputStream into a new byte array.
	 * Closes the stream when done.
	 * @param in the stream to copy from
	 * @return the new byte array that has been copied to
	 * @throws IOException in case of I/O errors
	 */
	public static byte[] copyToByteArray(InputStream in) throws IOException {
		ByteArrayOutputStream out = new ByteArrayOutputStream(BUFFER_SIZE);
		copy(in, out);
		return out.toByteArray();
	}


	//---------------------------------------------------------------------
	// Copy methods for java.io.Reader / java.io.Writer
	//---------------------------------------------------------------------

	/**
	 * Copy the contents of the given Reader to the given Writer.
	 * Closes both when done.
	 * @param in the Reader to copy from
	 * @param out the Writer to copy to
	 * @return the number of characters copied
	 * @throws IOException in case of I/O errors
	 */
	public static int copy(Reader in, Writer out) throws IOException {
		Assert.notNull(in, "No Reader specified");
		Assert.notNull(out, "No Writer specified");
		try {
			int byteCount = 0;
			char[] buffer = new char[BUFFER_SIZE];
			int bytesRead = -1;
			while ((bytesRead = in.read(buffer)) != -1) {
				out.write(buffer, 0, bytesRead);
				byteCount += bytesRead;
			}
			out.flush();
			return byteCount;
		}
		finally {
			try {
				in.close();
			}
			catch (IOException ex) {
			}
			try {
				out.close();
			}
			catch (IOException ex) {
			}
		}
	}

	/**
	 * Copy the contents of the given String to the given output Writer.
	 * Closes the write when done.
	 * @param in the String to copy from
	 * @param out the Writer to copy to
	 * @throws IOException in case of I/O errors
	 */
	public static void copy(String in, Writer out) throws IOException {
		Assert.notNull(in, "No input String specified");
		Assert.notNull(out, "No Writer specified");
		try {
			out.write(in);
		}
		finally {
			try {
				out.close();
			}
			catch (IOException ex) {
			}
		}
	}

	/**
	 * Copy the contents of the given Reader into a String.
	 * Closes the reader when done.
	 * @param in the reader to copy from
	 * @return the String that has been copied to
	 * @throws IOException in case of I/O errors
	 */
	public static String copyToString(Reader in) throws IOException {
		StringWriter out = new StringWriter();
		copy(in, out);
		return out.toString();
	}

}