VFS-2.0-RC1/sandbox/src/main/java/org/apache/commons/vfs/RACRandomAccessFile.java

/*
 * Copyright 2002-2005 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.vfs;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;

/**
 * Encapsulates a {@link RandomAccessContent} instance, allowing it to be used
 * as a {@link RandomAccessFile} instance.
 *
 * @author Elifarley Callado Coelho Cruz <elifarley@gmail.com>
 * @version 1.1, $LastChangedRevision: 1163 $, $LastChangedDate: 2006-12-13 03:18:57 +0000 (Qua, 13 Dez 2006) $
 */
public class RACRandomAccessFile extends RandomAccessFile implements RandomAccessContent
{
    private RandomAccessContent rac;
    protected final byte[] singleByteBuf = new byte[1];

    private static File createTempFile() throws IOException
    {
        return File.createTempFile("fraf", "");
    }

    private void deleteTempFile(File tempFile)
    {
        try
        {
            super.close();
        }
        catch (IOException ex)
        {
            throw new RuntimeException(ex);
        }
        finally
        {
            tempFile.delete();
        }
    }

    public RACRandomAccessFile(RandomAccessContent rac) throws IOException
    {
        this(createTempFile());
        this.rac = rac;
    }

    private RACRandomAccessFile(File tempFile) throws IOException
    {
        super(tempFile, "r");
        deleteTempFile(tempFile);
    }

    public long getFilePointer() throws IOException
    {
        return this.rac.getFilePointer();
    }

    public void seek(long pos) throws IOException
    {
        this.rac.seek(pos);
    }

    public int skipBytes(int n) throws IOException
    {
        return this.rac.skipBytes(n);
    }

    public long length() throws IOException
    {
        return this.rac.length();
    }

    /* (non-Javadoc)
         * @see org.ecc.base.io.FilterRandomAccessFile#setLength(long)
         */
    public void setLength(long newLength) throws IOException
    {
        throw new IOException("Underlying RandomAccessContent instance length cannot be modified.");
    }

    public InputStream getInputStream() throws IOException
    {
        return this.rac.getInputStream();
    }

    public void close() throws IOException
    {
        this.rac.close();
    }


    /**
     * @see java.io.RandomAccessFile#read(byte[])
     */
    public final int read(byte[] b) throws IOException
    {
        return read(b, 0, b.length);
    }

    /**
     * @see java.io.RandomAccessFile#read()
     */
    public final int read() throws IOException
    {
        final byte[] buf = this.singleByteBuf;
        int count = read(buf, 0, 1);
        return count < 0 ? -1 : (buf[0] & 0xFF);
    }

    public int read(byte[] b, int off, int len) throws IOException
    {
        this.rac.readFully(b, off, len);
        return len;
    }

    /**
     * @see java.io.RandomAccessFile#write(int)
     */
    public final void write(int b) throws IOException
    {
        final byte[] buf = this.singleByteBuf;
        buf[0] = (byte) b;
        write(buf, 0, 1);
    }

    /**
     * @see java.io.RandomAccessFile#write(byte[])
     */
    public final void write(byte[] b) throws IOException
    {
        write(b, 0, b.length);
    }

    /**
     * @see java.io.RandomAccessFile#write(byte[],int,int)
     */
    public void write(byte[] b, int off, int len) throws IOException
    {
        this.rac.write(b, off, len);
    }

}