PooledByteBufferOutputStream.java

/*
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

package com.facebook.imagepipeline.memory;

import java.io.IOException;
import java.io.OutputStream;

import com.facebook.common.internal.Throwables;

/**
 * An OutputStream that produces a PooledByteBuffer.
 *
 * <p> Expected use for such stream is to first write sequence of bytes to the stream and then call
 * toByteBuffer to produce PooledByteBuffer containing written data. After toByteBuffer returns
 * client can continue writing new data and call toByteBuffer over and over again.
 *
 * <p> Streams implementing this interface are closeable resources and need to be closed in order
 * to release underlying resources. Close is idempotent operation and after stream was closed, no
 * other method should be called. Streams subclassing PooledByteBufferOutputStream are not allowed
 * to throw IOException from close method.
 */
public abstract class PooledByteBufferOutputStream extends OutputStream {
  /**
   * Creates a PooledByteBuffer from the contents of the stream.
   * @return
   */
  public abstract PooledByteBuffer toByteBuffer();

  /**
   * Returns the total number of bytes written to this stream so far.
   * @return the number of bytes written to this stream.
   */
  public abstract int size();

  /**
   * Closes the stream.
   */
  @Override
  public void close() {
    try {
      super.close();
    } catch (IOException ioe) {
      // does not happen
      Throwables.propagate(ioe);
    }
  }
}