alluxio.network.protocol.databuffer.NioDataBuffer.java Source code

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Here is the source code for alluxio.network.protocol.databuffer.NioDataBuffer.java

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/*
 * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
 * (the "License"). You may not use this work except in compliance with the License, which is
 * available at www.apache.org/licenses/LICENSE-2.0
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied, as more fully set forth in the License.
 *
 * See the NOTICE file distributed with this work for information regarding copyright ownership.
 */

package alluxio.network.protocol.databuffer;

import alluxio.util.io.BufferUtils;

import com.google.common.base.Preconditions;
import io.netty.buffer.Unpooled;

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

/**
 * A DataBuffer with the underlying data being a {@link ByteBuffer}. If the backing ByteBuffer is
 * a direct ByteBuffer, {@link #release()} should only be called when all references to the
 * object are finished with it. For this reason, it is not recommended to share objects of this
 * class unless reference counting is implemented by the users of this class.
 */
public final class NioDataBuffer implements DataBuffer {
    private final ByteBuffer mBuffer;
    private final long mLength;

    /**
     * @param buffer The ByteBuffer representing the data
     * @param length The length of the ByteBuffer
     */
    public NioDataBuffer(ByteBuffer buffer, long length) {
        mBuffer = Preconditions.checkNotNull(buffer, "buffer");
        mLength = length;
    }

    @Override
    public Object getNettyOutput() {
        return Unpooled.wrappedBuffer(mBuffer);
    }

    @Override
    public long getLength() {
        return mLength;
    }

    @Override
    public ByteBuffer getReadOnlyByteBuffer() {
        ByteBuffer buffer = mBuffer.asReadOnlyBuffer();
        buffer.position(0);
        return buffer;
    }

    @Override
    public void readBytes(byte[] dst, int dstIndex, int length) {
        mBuffer.get(dst, dstIndex, length);
    }

    @Override
    public void readBytes(OutputStream outputStream, int length) throws IOException {
        Unpooled.wrappedBuffer(mBuffer).readBytes(outputStream, length).release();
    }

    @Override
    public void readBytes(ByteBuffer outputBuf) {
        outputBuf.put(mBuffer);
    }

    @Override
    public int readableBytes() {
        return mBuffer.remaining();
    }

    @Override
    public void release() {
        if (mBuffer.isDirect()) {
            BufferUtils.cleanDirectBuffer(mBuffer);
        }
    }
}