How to get memory usage of Tibco BW Job

package Libraries.Utils.GetJobsMemoryUsage;
import java.lang.reflect.*;
import java.util.*;
import java.util.concurrent.atomic.*;
import java.io.*;
import org.xml.sax.InputSource;

import com.tibco.xml.datamodel.XiNode;
import com.tibco.xml.datamodel.XiParserFactory;
import com.tibco.xml.xdata.xpath.Variable;
import com.tibco.xml.xdata.xpath.VariableList;
import com.tibco.pe.core.*;

public class GetJobsMemoryUsageJavaCode{

 public static JobPool getJobPool() {
  for (Field f : Engine.class.getDeclaredFields()) {
   if (f.getType().getName().endsWith("JobPool")) {
    f.setAccessible(true);
    try {
     return (JobPool) f.get(null);
    }
    catch (Throwable te) {
     throw new RuntimeException("Cannot access JobPool: "+te.getMessage(), te);
    }    
   }   
  }
  throw new RuntimeException("Cannot access JobPool");
 }

 public static long[] getJobIds() {
  try {
   return getJobPool().getJobIds();
  }
  catch (Throwable t) {
   throw new RuntimeException("Cannot access JobPool.getJobIds(): "+t.getMessage(), t);
  }
 }

 public static String getJobName(long id) {
  try {
   Object job = getJobPool().findJob(id);
   if (job!=null) {
    Method getWorkflow = Class.forName("com.tibco.pe.core.Job").getDeclaredMethod("getWorkflow", new Class<?>[0]);
    getWorkflow.setAccessible(true);
    com.tibco.pe.core.Workflow w = (com.tibco.pe.core.Workflow)getWorkflow.invoke(job);
    return w!=null ? w.getName() : "no-workflow-name";
   }
   else
    return null;
  }
  catch (Throwable t) {
   throw new RuntimeException("Cannot access Job data: "+t.getMessage(), t);
  }
 }

 public static VariableList getJobVariables(long jid, int trackId) {
  try {
   Method getAttributes = Class.forName("com.tibco.pe.core.Job").getDeclaredMethod("getAttributes", new Class<?>[] { int.class });
   getAttributes.setAccessible(true);
   return (VariableList) getAttributes.invoke(getJobPool().findJob(jid), trackId);
  }
  catch (Throwable t) {
   throw new RuntimeException("Cannot access job variables: "+t.getMessage(), t);
  }
 }

 public int getTrackId(long jid) {
  try {
   Method getter = Class.forName("com.tibco.pe.core.Job").getDeclaredMethod("getTrackId", new Class<?>[0]);
   getter.setAccessible(true);
   return (int) getter.invoke(getJobPool().findJob(jid));
  }
  catch (Throwable t) {
   throw new RuntimeException("Cannot access job methods: "+t.getMessage(), t);
  }
 }
/****** START SET/GET METHOD, DO NOT MODIFY *****/
 protected long jobId = 0;
 protected String[] usage = null;
 public long getjobId() {
  return jobId;
 }
 public void setjobId(long val) {
  jobId = val;
 }
 public String[] getusage() {
  return usage;
 }
 public void setusage(String[] val) {
  usage = val;
 }
/****** END SET/GET METHOD, DO NOT MODIFY *****/
 public GetJobsMemoryUsageJavaCode() {
 }
 public void invoke() throws Exception {
/* Available Variables: DO NOT MODIFY
 In  : long jobId
 Out : String[] usage
* Available Variables: DO NOT MODIFY *****/

LinkedList<String> usageList = new LinkedList<String>();
long ids[] = jobId > 0 ? new long[] { jobId } : getJobIds();

if (ids!=null) {
 StringBuilder sb = new StringBuilder();
 for (long id : ids) {
  String jobName = getJobName(id);
  sb.setLength(0); 
  AtomicLong mem = new AtomicLong(0);
  int currentTrackId = getTrackId(id);

  for (int trackId = 0; trackId < 4; trackId++) {
   VariableList varList = trackId == currentTrackId ? null : getJobVariables(id, trackId);
   if (varList!=null) {  
    for (Object varName : varList.getVariableNames()) {
     Variable v = varList.getVariable(varName.toString());
     long size = 0;
     if (v.getValue()==null)
      size = (v.getNumber()+"").length();
     else {
      final AtomicInteger cnt = new AtomicInteger(0);
      OutputStream cos = new OutputStream() {
       public void write(int i) { cnt.addAndGet(4); }
       public void write(byte bytes[], int off, int len) throws IOException { cnt.addAndGet(len); }
      };
      com.tibco.xml.datamodel.helpers.XiSerializer.serialize( v.getValue(), cos, "utf-8", true );
      size = cnt.get();
     }
     sb.append(varName).append('[').append(trackId).append(']').append("=").append(size).append("|");  
     mem.addAndGet(size);
    } 
   }
  }  
  sb.insert(0, jobName+"="+mem.longValue()+"|");
  usageList.add(sb.toString());
 } 
}
usage = usageList.toArray(new String[0]);}
}