content: /*
   * Copyright (C) 2010-2101 Alibaba Group Holding Limited.
   *
   * 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.alibaba.otter.shared.common.utils.cmd;
  
  //~--- non-JDK imports --------------------------------------------------------
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.io.OutputStream;
  
  import org.apache.commons.io.IOUtils;
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.lang.SystemUtils;
  
  /**
   * A simple thread that copies one stream to another. Useful for copying a process's output/error streams to this
   * process's output/error streams.
   */
  public class StreamCopier extends Thread {
  
      protected final String         identifier;
      protected final OutputStream   out;
      protected final BufferedReader reader;
  
      public StreamCopier(InputStream stream, OutputStream out){
          this(stream, out, null);
      }
  
      public StreamCopier(InputStream stream, OutputStream out, String identifier){
          if ((stream == null) || (out == null)) {
              throw new AssertionError("null streams not allowed");
          }
  
          this.reader = new BufferedReader(new InputStreamReader(stream));
          this.out = out;
          this.identifier = identifier;
          this.setName("Stream Copier");
          this.setDaemon(true);
      }
  
      public void run() {
          try {
              StringBuffer buf = new StringBuffer();
              String line = null;
  
              while ((line = reader.readLine()) != null) {
                  if (identifier != null) {
                      line = identifier + line;
                  }
  
                  if (false == StringUtils.isBlank(line)) {
                      buf.append(line).append(SystemUtils.LINE_SEPARATOR);
                  }
              }
  
              out.write(buf.toString().getBytes());
              out.flush();
          } catch (IOException ioe) {
              //ignore
          } finally {
              IOUtils.closeQuietly(reader);
          }
      }
  }
  