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

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/**
 * 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.ServiceRuntimeException;

import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Iterator;

public class FramingInputStream extends DataInputStream implements Iterable {
  
  public FramingInputStream(InputStream in) {
    super(in);
  }

  public byte[] readFrame() throws IOException {
    int i = readInt();
    if(i == -1) {
      return null;
    }
    byte[] b = new byte[i];
    readFully(b);
    return b;
  }
  
  @Override
  public Iterator iterator() {
    try {
      return new Iterator() {
        byte[] cur = readFrame();
        @Override
        public boolean hasNext() {
          return cur != null;
        }
  
        @Override
        public byte[] next() {
          byte[] ret = cur;
          try {
            cur = readFrame();
          } catch (IOException e) {
            throw new ServiceRuntimeException(e);
          }
          return ret;
        }
  
        @Override
        public void remove() {
          throw new UnsupportedOperationException();
        }
      };
    } catch(IOException e) {
      throw new ServiceRuntimeException(e);
    }
  }

}