/*
    * 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.hadoop.chukwa.datacollection.writer;
  
  
  import java.io.*;
  import java.util.List;
  import org.apache.hadoop.chukwa.Chunk;
  import org.apache.hadoop.chukwa.ChunkImpl;
  import org.apache.hadoop.conf.Configuration;
  
  public class InMemoryWriter implements ChukwaWriter {
  
    ByteArrayOutputStream buf;
  
    public void close() {
      buf.reset();
    }
  
    public void init(Configuration conf) throws WriterException {
      buf = new ByteArrayOutputStream();
    }
  
    public void add(Chunk data) throws WriterException {
      DataOutputStream dos = new DataOutputStream(buf);
      try {
        data.write(dos);
      } catch (IOException e) {
        e.printStackTrace();
        throw new WriterException(e);
      }
      synchronized (this) {
        notify();
      }
    }
  
    @Override
    public CommitStatus add(List<Chunk> chunks) throws WriterException {
      for (Chunk chunk : chunks) {
        add(chunk);
      }
      return COMMIT_OK;
    }
  
    DataInputStream dis = null;
  
    /**
     * Try to read bytes, waiting up to ms
     * 
     * @param bytes amount to try to read
     * @param ms time to wait
     * @return a newly read-in chunk
     * @throws IOException
     */
    public Chunk readOutChunk(int bytes, int ms) throws IOException {
  
      long readStartTime = System.currentTimeMillis();
      try {
        while (buf.size() < bytes) {
          synchronized (this) {
            long timeLeft = ms - System.currentTimeMillis() + readStartTime;
            if (timeLeft > 0)
              wait(timeLeft);
          }
        }
        if (dis == null)
          dis = new DataInputStream(new ByteArrayInputStream(buf.toByteArray()));
        return ChunkImpl.read(dis);
      } catch (InterruptedException e) {
        Thread.currentThread().interrupt();
        return null;
      }
    }
  
  }