common/src/main/java/org/apache/nemo/common/DirectByteArrayOutputStream.java

/*
 * 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.nemo.common;

import java.io.ByteArrayOutputStream;

/**
 * This class represents a custom implementation of {@link ByteArrayOutputStream},
 * which enables to get bytes buffer directly (without memory copy).
 * TODO #370: Substitute ByteArrayOutputStream with java.nio.ByteBuffer
 */
public final class DirectByteArrayOutputStream extends ByteArrayOutputStream {

  /**
   * Default constructor.
   */
  public DirectByteArrayOutputStream() {
    super();
  }

  /**
   * Constructor specifying the size.
   *
   * @param size the initial size.
   */
  public DirectByteArrayOutputStream(final int size) {
    super(size);
  }

  /**
   * Note that serializedBytes include invalid bytes.
   * So we have to use it with the actualLength by using size() whenever needed.
   *
   * @return the buffer where data is stored.
   */
  public byte[] getBufDirectly() {
    return buf;
  }
}