com.microsoft.reef.io.storage.FramingOutputStream Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of reef-io Show documentation
There is a newer version: 0.9
/**
 * Copyright (C) 2013 Microsoft Corporation
 *
 * Licensed 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 com.microsoft.reef.io.storage;

import com.microsoft.reef.exception.evaluator.ServiceException;
import com.microsoft.reef.exception.evaluator.StorageException;
import com.microsoft.reef.io.Accumulable;
import com.microsoft.reef.io.Accumulator;

import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;

public class FramingOutputStream extends OutputStream implements Accumulable {
	
  private final ByteArrayOutputStream baos;
  private final DataOutputStream o;
  private long offset;
  private boolean closed;
  
  public FramingOutputStream(OutputStream o) {
    if (!(o instanceof DataOutputStream)) {
      this.o = new DataOutputStream(o);
    } else {
      this.o = (DataOutputStream) o;
    }
    this.baos = new ByteArrayOutputStream();
  }

  public void nextFrame() throws StorageException {
    try {
      o.writeInt(baos.size());
      offset+=4;
      baos.writeTo(o);
      baos.reset();
    } catch (IOException e) {
      throw new StorageException(e);
    }
  }
  public long getCurrentOffset() {
    return offset;
  }
  @Override
  public void write(int b) throws IOException {
    baos.write(b);
    offset++;;
  }

  @Override
  public void write(byte[] b) throws IOException {
    baos.write(b);
    offset+=b.length;
  }

  @Override
  public void write(byte[] b, int offset, int length) throws IOException {
    baos.write(b, offset, length);
    offset+=length;
  }

  @Override
  public void flush() {
    // no-op.
  }

  @Override
  public void close() throws IOException {
    if(!closed) {
      try {
        if (this.offset > 0) nextFrame();
      } catch(StorageException e) {
        throw (IOException)e.getCause();
      }
      o.writeInt(-1);
      o.close();
      closed = true;
    }
  }

  @Override
  public Accumulator accumulator() throws StorageException {
    @SuppressWarnings("resource")
    final FramingOutputStream fos = this;
    return new Accumulator() {

      @Override
      public void add(byte[] datum) throws ServiceException {
        try {
          o.writeInt(datum.length);
          offset+=4;
          o.write(datum);
          offset+=datum.length;
        } catch (IOException e) {
          throw new ServiceException(e);
        }
        
      }

      @Override
      public void close() throws ServiceException {
        try {
          o.writeInt(-1);
          offset+=4;
          o.close();
          fos.closed = true;
        } catch (IOException e) {
          throw new ServiceException(e);
        }
      }
      
    };
  }

}