tachyon.network.protocol.RPCBlockResponse.java Source code

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Here is the source code for tachyon.network.protocol.RPCBlockResponse.java

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/*
 * Licensed to the University of California, Berkeley under one or more contributor license
 * agreements. See the NOTICE file distributed with this work for additional information regarding
 * copyright ownership. The ASF licenses this file to You 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 tachyon.network.protocol;

import java.nio.ByteBuffer;

import com.google.common.primitives.Longs;
import com.google.common.primitives.Shorts;

import io.netty.buffer.ByteBuf;

import tachyon.network.protocol.databuffer.DataBuffer;
import tachyon.network.protocol.databuffer.DataByteBuffer;
import tachyon.worker.DataServerMessage;

/**
 * This represents the response of a {@link RPCBlockRequest}.
 */
public class RPCBlockResponse extends RPCResponse {
    private final long mBlockId;
    private final long mOffset;
    private final long mLength;
    private final DataBuffer mData;

    public RPCBlockResponse(long blockId, long offset, long length, DataBuffer data) {
        mBlockId = blockId;
        mOffset = offset;
        mLength = length;
        mData = data;
    }

    public Type getType() {
        return Type.RPC_BLOCK_RESPONSE;
    }

    /**
     * Creates a {@link RPCBlockResponse} that indicates an error for
     * the given block.
     *
     * @param blockId The Id of block requested
     * @return the new error RPCBlockResponse created.
     */
    public static RPCBlockResponse createErrorResponse(final long blockId) {
        return new RPCBlockResponse(-blockId, 0, 0, null);
    }

    /**
     * Decode the input {@link ByteBuf} into a {@link RPCBlockResponse} object and return it.
     *
     * @param in the input {@link ByteBuf}
     * @return The decoded RPCBlockResponse object
     */
    public static RPCBlockResponse decode(ByteBuf in) {
        // TODO: remove this short when client also uses netty.
        in.readShort();
        long blockId = in.readLong();
        long offset = in.readLong();
        long length = in.readLong();
        DataBuffer data = null;
        if (length > 0) {
            // TODO: look into accessing Netty ByteBuf directly, to avoid copying the data.
            ByteBuffer buffer = ByteBuffer.allocate((int) length);
            in.readBytes(buffer);
            data = new DataByteBuffer(buffer, (int) length);
        }
        return new RPCBlockResponse(blockId, offset, length, data);
    }

    @Override
    public int getEncodedLength() {
        // TODO: adjust the length when client also uses netty.
        // 3 longs (mBLockId, mOffset, mLength) + 1 short (DATA_SERVER_REQUEST_MESSAGE)
        return Longs.BYTES * 3 + Shorts.BYTES;
    }

    @Override
    public void encode(ByteBuf out) {
        // TODO: remove this short when client also uses netty.
        out.writeShort(DataServerMessage.DATA_SERVER_RESPONSE_MESSAGE);
        out.writeLong(mBlockId);
        out.writeLong(mOffset);
        out.writeLong(mLength);
        // The actual payload is not encoded here, since the RPCMessageEncoder will transfer it in a
        // more efficient way.
    }

    @Override
    public DataBuffer getPayloadDataBuffer() {
        return mData;
    }

    public long getBlockId() {
        return mBlockId;
    }

    public long getLength() {
        return mLength;
    }

    public long getOffset() {
        return mOffset;
    }
}