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The Async Http Client (AHC) classes.

There is a newer version: 3.0.0

/*
 * Copyright (c) 2010-2012 Sonatype, Inc. All rights reserved.
 *
 * This program is licensed to you under the Apache License Version 2.0,
 * and you may not use this file except in compliance with the Apache License Version 2.0.
 * You may obtain a copy of the Apache License Version 2.0 at http://www.apache.org/licenses/LICENSE-2.0.
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the Apache License Version 2.0 is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Apache License Version 2.0 for the specific language governing permissions and limitations there under.
 */
package org.asynchttpclient.handler.resumable;

import static org.asynchttpclient.util.MiscUtils.closeSilently;

import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;

/**
 * A {@link org.asynchttpclient.handler.resumable.ResumableListener} which use a {@link RandomAccessFile} for storing the received bytes.
 */
public class ResumableRandomAccessFileListener implements ResumableListener {
    private final RandomAccessFile file;

    public ResumableRandomAccessFileListener(RandomAccessFile file) {
        this.file = file;
    }

    /**
     * This method uses the last valid bytes written on disk to position a {@link RandomAccessFile}, allowing
     * resumable file download.
     *
     * @param buffer a {@link ByteBuffer}
     * @throws IOException exception while writing into the file
     */
    public void onBytesReceived(ByteBuffer buffer) throws IOException {
        file.seek(file.length());
        if (buffer.hasArray()) {
            file.write(buffer.array(), buffer.arrayOffset() + buffer.position(), buffer.remaining());
        } else { // if the buffer is direct or backed by a String...
            byte[] b = new byte[buffer.remaining()];
            int pos = buffer.position();
            buffer.get(b);
            buffer.position(pos);
            file.write(b);
        }
    }

    /**
     * {@inheritDoc}
     */
    public void onAllBytesReceived() {
        closeSilently(file);
    }

    /**
     * {@inheritDoc}
     */
    public long length() {
        try {
            return file.length();
        } catch (IOException e) {
            return 0;
        }
    }
}