/*

  * 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.giraph.utils;

 import java.io.BufferedReader;

 import java.io.IOException;

 import java.io.InputStreamReader;

 import java.io.PrintStream;

 import java.lang.management.ManagementFactory;

 import java.nio.charset.Charset;

 import java.util.Date;

 /**

  * Helper to run jmap and print the output

  */

 public class JMap {

   /** Arguments to pass in to command */

   public static final String ARGS = " -histo ";

   /** This option will print out onlu live objects */

   private static String LIVE_HISTO_OPTION = " -histo:live ";

   /** Do not construct */

   protected JMap() { }

   /**

    * Get the process ID of the current running process

    *

    * @return Integer process ID

    */

   public static int getProcessId() {

     String processId = ManagementFactory.getRuntimeMXBean().getName();

     if (processId.contains("@")) {

       processId = processId.substring(0, processId.indexOf("@"));

     }

     return Integer.parseInt(processId);

   }

   /**

    * Run jmap, print numLines of output from it to stderr.

    *

    * @param numLines Number of lines to print

    * @param liveObjectsOnly Should we only print non GC-able objects?

    * @param jmapPath Path to jmap binary

    */

   public static void heapHistogramDump(int numLines,

                                        boolean liveObjectsOnly,

                                        String jmapPath) {

     heapHistogramDump(numLines, liveObjectsOnly, System.err, jmapPath);

   }

   /**

    * Run jmap, print numLines of output from it to stderr.

    *

    * @param numLines Number of lines to print

    * @param jmapPath Path to jmap binary

    */

   public static void heapHistogramDump(int numLines, String jmapPath) {

     heapHistogramDump(numLines, System.err, jmapPath);

   }

   /**

    * Run jmap, print numLines of output from it to stream passed in.

    *

    * @param numLines Number of lines to print

    * @param printStream Stream to print to

    * @param jmapPath Path to jmap binary

    */

   public static void heapHistogramDump(int numLines, PrintStream printStream,

                                        String jmapPath) {

     heapHistogramDump(numLines, false, printStream, jmapPath);

   }

   /**

    * Run jmap, print numLines of output from it to stream passed in.

    *

    * @param numLines Number of lines to print

    * @param liveObjectsOnly Should we only print non GC-able objects?

    * @param printStream Stream to print to

    * @param jmapPath Path to jmap binary

    */

   private static void heapHistogramDump(int numLines,

                                         boolean liveObjectsOnly,

                                         PrintStream printStream,

                                         String jmapPath) {

     try {

       String args = liveObjectsOnly ? LIVE_HISTO_OPTION : ARGS;

       Process p = Runtime.getRuntime().exec(jmapPath + args + getProcessId());

       BufferedReader in = new BufferedReader(

           new InputStreamReader(p.getInputStream(), Charset.defaultCharset()));

       printStream.println("JMap " +

           (liveObjectsOnly ? "histo:live" : "histo") +

           " dump at " + new Date());

       String line = in.readLine();

       for (int i = 0; i < numLines && line != null; ++i) {

         printStream.println("--\t" + line);

         line = in.readLine();

       }

       in.close();

     } catch (IOException e) {

       e.printStackTrace();

     }

   }

 }