PeriodicGarbageCollector


1   /*
2    ************************************************************************************
3    * Copyright (C) 2001-2006 Openbravo S.L.
4    * Licensed under the Apache Software License version 2.0
5    * You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
6    * Unless required by applicable law or agreed to  in writing,  software  distributed
7    * under the License is distributed  on  an  "AS IS"  BASIS,  WITHOUT  WARRANTIES  OR
8    * CONDITIONS OF ANY KIND, either  express  or  implied.  See  the  License  for  the
9    * specific language governing permissions and limitations under the License.
10   ************************************************************************************
11  */
12  /** 
13   * PeriodicGarbageCollector.  
14   * @version 1.0.0 11/5/2004
15   * @author Carlos Romero Herrero
16  */
17  package org.openbravo.base;
18  import java.io.*;
19  import org.apache.log4j.Logger ;
20  
21  /**
22   * PeriodicGarbageCollector
23   * @version 1.0.0 11/5/2004
24   * @author Carlos Romero Herrero
25  */
26  public class PeriodicGarbageCollector implements Runnable   {
27    static Logger log4j = Logger.getLogger(PeriodicGarbageCollector.class);
28    private Thread   runner;
29    private long seconds;
30  
31    /**
32     * Creates a new periodic garbage collector<br>
33     * time:            Number in seconds between two garbage collections<br>
34     */
35    public PeriodicGarbageCollector(long seconds) throws IOException 
36    {
37      // Fire up the background housekeeping thread
38      runner = new Thread  (this);
39      runner.start();
40      this.seconds = seconds;
41    }
42  
43  
44    /**
45     * Housekeeping thread.  Runs in the background with low CPU overhead.
46     * This method acts as fault tolerance for bad connection/statement programming.
47     */
48    public void run()
49    {
50      boolean forever = true;
51  
52      while(forever) {
53        try { 
54          if (log4j.isDebugEnabled()) log4j.debug("Sleeping for "+seconds+" seconds.");
55          Thread.sleep((seconds*1000)); 
56          if (log4j.isDebugEnabled()) log4j.debug("gc begins");
57          long inicio = System.currentTimeMillis();
58          System.gc(); 
59          long fin = System.currentTimeMillis();
60          if (log4j.isDebugEnabled()) log4j.debug("gc ended: "+(fin-inicio)+" miliseconds");
61          if (log4j.isDebugEnabled()) log4j.debug("Finalization begins");
62          inicio = System.currentTimeMillis();
63          System.runFinalization();
64          fin = System.currentTimeMillis();
65          if (log4j.isDebugEnabled()) log4j.debug("Finalization ended: "+(fin-inicio)+" miliseconds");
66          if (log4j.isDebugEnabled()) log4j.debug(mostrarMemoria());
67        }  // Wait time miliseconds for next cycle
68        catch(InterruptedException   e) {
69          // Returning from the run method sets the internal 
70          // flag referenced by Thread.isAlive() to false.
71          // This is required because we don't use stop() to 
72          // shutdown this thread.
73          return;
74        }
75      }
76  
77    } // End run
78  
79    public String   mostrarMemoria(String   texto) {
80      return (texto + "\n" + mostrarMemoria());
81    }
82  
83    public String   mostrarMemoria() {
84      StringBuffer   result = new StringBuffer  ();
85      result.append("Maximum memory :").append(Runtime.getRuntime().maxMemory());
86      result.append("Total memory  :").append(Runtime.getRuntime().totalMemory());
87      result.append("Free memory  :").append(Runtime.getRuntime().freeMemory());
88      result.append("% free memory:").append((100*Runtime.getRuntime().freeMemory()/Runtime.getRuntime().totalMemory())).append("%");
89      return result.toString();
90    }
91  
92  }// End class
93  
94
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