Java tutorial
/* * 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 io.netty.buffer.ByteBuf; import tachyon.network.protocol.databuffer.DataBuffer; import tachyon.network.protocol.databuffer.DataByteBuffer; /** * This represents the request to write a block to a DataServer. */ public final class RPCBlockWriteRequest extends RPCRequest { private final long mSessionId; private final long mBlockId; private final long mOffset; private final long mLength; private final DataBuffer mData; public RPCBlockWriteRequest(long sessionId, long blockId, long offset, long length, DataBuffer data) { mSessionId = sessionId; mBlockId = blockId; mOffset = offset; mLength = length; mData = data; } @Override public Type getType() { return Type.RPC_BLOCK_WRITE_REQUEST; } /** * Decodes the input {@link ByteBuf} into a {@link RPCBlockWriteRequest} object and returns it. * * @param in the input {@link ByteBuf} * @return The decoded RPCBlockWriteRequest object */ public static RPCBlockWriteRequest decode(ByteBuf in) { long sessionId = in.readLong(); long blockId = in.readLong(); long offset = in.readLong(); long length = in.readLong(); DataBuffer data = null; if (length > 0) { // TODO(hy): 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 RPCBlockWriteRequest(sessionId, blockId, offset, length, data); } @Override public int getEncodedLength() { // 4 longs (mSessionId, mBlockId, mOffset, mLength) return Longs.BYTES * 4; } @Override public void encode(ByteBuf out) { out.writeLong(mSessionId); 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 getSessionId() { return mSessionId; } public long getBlockId() { return mBlockId; } public long getLength() { return mLength; } public long getOffset() { return mOffset; } }