alluxio.network.protocol.RPCBlockReadRequest.java Source code

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Here is the source code for alluxio.network.protocol.RPCBlockReadRequest.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;

import com.google.common.base.Objects;
import com.google.common.base.Preconditions;
import com.google.common.primitives.Longs;
import io.netty.buffer.ByteBuf;

import javax.annotation.concurrent.ThreadSafe;

/**
 * This represents an RPC request to read a block from a DataServer.
 */
@ThreadSafe
public final class RPCBlockReadRequest extends RPCRequest {
    private final long mBlockId;
    private final long mOffset;
    private final long mLength;
    private final long mLockId;
    private final long mSessionId;

    /**
     * Constructs a new RPC request to read a block from a DataServer.
     *
     * @param blockId the id of the block
     * @param offset the block offset to begin reading at
     * @param length the number of bytes to read
     * @param lockId the id of the block lock that is held by the client
     * @param sessionId the id of the client session
     */
    public RPCBlockReadRequest(long blockId, long offset, long length, long lockId, long sessionId) {
        mBlockId = blockId;
        mOffset = offset;
        mLength = length;
        mLockId = lockId;
        mSessionId = sessionId;
    }

    @Override
    public Type getType() {
        return Type.RPC_BLOCK_READ_REQUEST;
    }

    /**
     * Decodes the input {@link ByteBuf} into a {@link RPCBlockReadRequest} object and returns it.
     *
     * @param in the input {@link ByteBuf}
     * @return The decoded RPCBlockReadRequest object
     */
    public static RPCBlockReadRequest decode(ByteBuf in) {
        long blockId = in.readLong();
        long offset = in.readLong();
        long length = in.readLong();
        long lockId = in.readLong();
        long sessionId = in.readLong();
        return new RPCBlockReadRequest(blockId, offset, length, lockId, sessionId);
    }

    @Override
    public int getEncodedLength() {
        // 5 longs (mBLockId, mOffset, mLength, mLockId, mSessionId)
        return Longs.BYTES * 5;
    }

    @Override
    public void encode(ByteBuf out) {
        out.writeLong(mBlockId);
        out.writeLong(mOffset);
        out.writeLong(mLength);
        out.writeLong(mLockId);
        out.writeLong(mSessionId);
    }

    @Override
    public void validate() {
        Preconditions.checkState(mOffset >= 0, "Offset cannot be negative: %s", mOffset);
        Preconditions.checkState(mLength >= 0 || mLength == -1, "Length cannot be negative (except for -1): %s",
                mLength);
    }

    @Override
    public String toString() {
        return Objects.toStringHelper(this).add("blockId", mBlockId).add("offset", mOffset).add("length", mLength)
                .add("lockId", mLockId).add("sessionId", mSessionId).toString();
    }

    /**
     * @return the id of the block
     */
    public long getBlockId() {
        return mBlockId;
    }

    /**
     * @return the number of bytes to read
     */
    public long getLength() {
        return mLength;
    }

    /**
     * @return the block offset to begin reading at
     */
    public long getOffset() {
        return mOffset;
    }

    /**
     * @return the id of the lock
     */
    public long getLockId() {
        return mLockId;
    }

    /**
     * @return the id of the session
     */
    public long getSessionId() {
        return mSessionId;
    }
}