alluxio.network.protocol.RPCFileWriteRequest.java Source code

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Here is the source code for alluxio.network.protocol.RPCFileWriteRequest.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 alluxio.network.protocol.databuffer.DataBuffer;
import alluxio.network.protocol.databuffer.DataByteBuffer;

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

import java.nio.ByteBuffer;

import javax.annotation.concurrent.ThreadSafe;

/**
 * This represents the request to write a file to the ufs through an Alluxio Worker. The file
 * must have been previously created through an RPC call.
 */
@ThreadSafe
public final class RPCFileWriteRequest extends RPCRequest {
    private final long mTempUfsFileId;
    private final long mOffset;
    private final long mLength;
    private final DataBuffer mData;

    /**
     * Constructs a new request to write to a ufs file through an Alluxio Worker.
     *
     * @param tempUfsFileId the worker specific ufs file id
     * @param offset the file offset to begin writing at
     * @param length the number of bytes to write
     * @param data the data
     */
    public RPCFileWriteRequest(long tempUfsFileId, long offset, long length, DataBuffer data) {
        mTempUfsFileId = tempUfsFileId;
        mOffset = offset;
        mLength = length;
        mData = data;
    }

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

    /**
     * Decodes the input {@link ByteBuf} into a {@link RPCFileWriteRequest} object and returns it.
     *
     * @param in the input {@link ByteBuf}
     * @return The decoded RPCFileWriteRequest object
     */
    public static RPCFileWriteRequest decode(ByteBuf in) {
        long tempUfsFileId = in.readLong();
        long offset = in.readLong();
        long length = in.readLong();
        // TODO(gene): Look into accessing Netty ByteBuf directly, to avoid copying the data.
        // Length will always be greater than 0 if the request is not corrupted. If length is negative,
        // ByteBuffer.allocate will fail. If length is 0 this will become a no-op but still go through
        // the necessary calls to validate the tempUfsFileId. If length is positive, the request will
        // proceed as normal
        ByteBuffer buffer = ByteBuffer.allocate((int) length);
        in.readBytes(buffer);
        DataByteBuffer data = new DataByteBuffer(buffer, (int) length);
        return new RPCFileWriteRequest(tempUfsFileId, offset, length, data);
    }

    @Override
    public int getEncodedLength() {
        // 3 longs (mTempUfsFileId, mOffset, mLength)
        return Longs.BYTES * 3;
    }

    @Override
    public void encode(ByteBuf out) {
        out.writeLong(mTempUfsFileId);
        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;
    }

    @Override
    public String toString() {
        return Objects.toStringHelper(this).add("tempUfsFileId", mTempUfsFileId).add("offset", mOffset)
                .add("length", mLength).toString();
    }

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

    /**
     * @return the worker specific ufs file id
     */
    public long getTempUfsFileId() {
        return mTempUfsFileId;
    }

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

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