| /** |
| * Licensed to the Apache Software Foundation (ASF) 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 org.apache.hadoop.ipc; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.io.DataOutputStream; |
| import java.io.IOException; |
| import java.io.OutputStream; |
| import java.util.Arrays; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| |
| @InterfaceAudience.Private |
| /** generates byte-length framed buffers. */ |
| public class ResponseBuffer extends DataOutputStream { |
| |
| public ResponseBuffer() { |
| this(1024); |
| } |
| |
| public ResponseBuffer(int capacity) { |
| super(new FramedBuffer(capacity)); |
| } |
| |
| // update framing bytes based on bytes written to stream. |
| private FramedBuffer getFramedBuffer() { |
| FramedBuffer buf = (FramedBuffer)out; |
| buf.setSize(written); |
| return buf; |
| } |
| |
| public void writeTo(OutputStream out) throws IOException { |
| getFramedBuffer().writeTo(out); |
| } |
| |
| byte[] toByteArray() { |
| return getFramedBuffer().toByteArray(); |
| } |
| |
| int capacity() { |
| return ((FramedBuffer)out).capacity(); |
| } |
| |
| void setCapacity(int capacity) { |
| ((FramedBuffer)out).setCapacity(capacity); |
| } |
| |
| void ensureCapacity(int capacity) { |
| if (((FramedBuffer)out).capacity() < capacity) { |
| ((FramedBuffer)out).setCapacity(capacity); |
| } |
| } |
| |
| ResponseBuffer reset() { |
| written = 0; |
| ((FramedBuffer)out).reset(); |
| return this; |
| } |
| |
| private static class FramedBuffer extends ByteArrayOutputStream { |
| private static final int FRAMING_BYTES = 4; |
| FramedBuffer(int capacity) { |
| super(capacity + FRAMING_BYTES); |
| reset(); |
| } |
| @Override |
| public int size() { |
| return count - FRAMING_BYTES; |
| } |
| void setSize(int size) { |
| buf[0] = (byte)((size >>> 24) & 0xFF); |
| buf[1] = (byte)((size >>> 16) & 0xFF); |
| buf[2] = (byte)((size >>> 8) & 0xFF); |
| buf[3] = (byte)((size >>> 0) & 0xFF); |
| } |
| int capacity() { |
| return buf.length - FRAMING_BYTES; |
| } |
| void setCapacity(int capacity) { |
| buf = Arrays.copyOf(buf, capacity + FRAMING_BYTES); |
| } |
| @Override |
| public void reset() { |
| count = FRAMING_BYTES; |
| setSize(0); |
| } |
| }; |
| } |