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A lightweight library to execute external processes from Java.
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/*
 * Copyright (C) 2014 ZeroTurnaround 
 * Contains fragments of code from Apache Commons Exec, rights owned
 * by Apache Software Foundation (ASF).
 *
 * 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.
 * 
 * NOTICE: This file originates from the Apache Commons Exec package.
 * It has been modified to fit our needs.
 * 
 * The following is the original header of the file in Apache Commons Exec:  
 * 
 *   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.zeroturnaround.exec.stream;

import java.io.InputStream;
import java.io.OutputStream;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Copies all data from an System.input stream to an output stream of the executed process.
 *
 * @author mkleint
 */
public class InputStreamPumper implements Runnable {

  private static final Logger log = LoggerFactory.getLogger(InputStreamPumper.class);

  public static final int SLEEPING_TIME = 100;

  /** the input stream to pump from */
  private final InputStream is;

  /** the output stream to pmp into */
  private final OutputStream os;

  /** flag to stop the stream pumping */
  private volatile boolean stop;

  /**
   * Create a new stream pumper.
   *
   * @param is input stream to read data from
   * @param os output stream to write data to.
   */
  public InputStreamPumper(final InputStream is, final OutputStream os) {
    this.is = is;
    this.os = os;
    this.stop = false;
  }

  /**
   * Copies data from the input stream to the output stream. Terminates as
   * soon as the input stream is closed or an error occurs.
   */
  public void run() {
    try {
      while (!stop) {
        while (is.available() > 0 && !stop) {
          os.write(is.read());
        }
        os.flush();
        Thread.sleep(SLEEPING_TIME);
      }
    }
    catch (Exception e) {
      log.error("Got exception while reading/writing the stream", e);
    }
  }

  public void stopProcessing() {
    stop = true;
  }

}