network/util/ByteArrayWritableChannel.java

0001 /*
0002  * Licensed to the Apache Software Foundation (ASF) under one or more
0003  * contributor license agreements.  See the NOTICE file distributed with
0004  * this work for additional information regarding copyright ownership.
0005  * The ASF licenses this file to You under the Apache License, Version 2.0
0006  * (the "License"); you may not use this file except in compliance with
0007  * the License.  You may obtain a copy of the License at
0008  *
0009  *    http://www.apache.org/licenses/LICENSE-2.0
0010  *
0011  * Unless required by applicable law or agreed to in writing, software
0012  * distributed under the License is distributed on an "AS IS" BASIS,
0013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
0014  * See the License for the specific language governing permissions and
0015  * limitations under the License.
0016  */
0017
0018 package org.apache.spark.network.util;
0019
0020 import java.nio.ByteBuffer;
0021 import java.nio.channels.WritableByteChannel;
0022
0023 /**
0024  * A writable channel that stores the written data in a byte array in memory.
0025  */
0026 public class ByteArrayWritableChannel implements WritableByteChannel {
0027
0028   private final byte[] data;
0029   private int offset;
0030
0031   public ByteArrayWritableChannel(int size) {
0032     this.data = new byte[size];
0033   }
0034
0035   public byte[] getData() {
0036     return data;
0037   }
0038
0039   public int length() {
0040     return offset;
0041   }
0042
0043   /** Resets the channel so that writing to it will overwrite the existing buffer. */
0044   public void reset() {
0045     offset = 0;
0046   }
0047
0048   /**
0049    * Reads from the given buffer into the internal byte array.
0050    */
0051   @Override
0052   public int write(ByteBuffer src) {
0053     int toTransfer = Math.min(src.remaining(), data.length - offset);
0054     src.get(data, offset, toTransfer);
0055     offset += toTransfer;
0056     return toTransfer;
0057   }
0058
0059   @Override
0060   public void close() {
0061
0062   }
0063
0064   @Override
0065   public boolean isOpen() {
0066     return true;
0067   }
0068
0069 }