webconsole-plugins/memoryusage/src/main/java/org/apache/felix/webconsole/plugins/memoryusage/internal/MemoryUsageSupport.java - felix-dev - Git at Google

 /*
  * 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.felix.webconsole.plugins.memoryusage.internal;

 import java.io.File;
 import java.io.PrintStream;
 import java.lang.management.ManagementFactory;
 import java.lang.management.MemoryMXBean;
 import java.lang.management.MemoryNotificationInfo;
 import java.lang.management.MemoryPoolMXBean;
 import java.lang.management.MemoryUsage;
 import java.lang.reflect.Method;
 import java.math.BigDecimal;
 import java.math.RoundingMode;
 import java.util.Arrays;
 import java.util.Date;
 import java.util.List;
 import java.util.NoSuchElementException;
 import java.util.TreeSet;

 import javax.management.ListenerNotFoundException;
 import javax.management.MBeanServer;
 import javax.management.Notification;
 import javax.management.NotificationEmitter;
 import javax.management.NotificationListener;
 import javax.management.ObjectName;

 import org.osgi.framework.BundleContext;
 import org.osgi.framework.Constants;
 import org.osgi.framework.InvalidSyntaxException;
 import org.osgi.framework.ServiceEvent;
 import org.osgi.framework.ServiceListener;
 import org.osgi.framework.ServiceReference;
 import org.osgi.service.log.LogService;

 final class MemoryUsageSupport implements NotificationListener, ServiceListener
 {

     // This is the name of the HotSpot Diagnostic MBean
     private static final String HOTSPOT_BEAN_NAME = "com.sun.management:type=HotSpotDiagnostic";

     // to get the LogService
     private final BundleContext context;

     // the default dump location: the dumps folder in the bundle private data
     // or the current working directory
     private final File defaultDumpLocation;

     // the default threshold value
     private final int defaultThreshold;

     // the minimum number of milliseconds between two consecutive memory
     // dumps written. this setting allows limitting the generation of memory
     // dumps if memory consumption is oscillating around the memory
     // threshold value
     private long minDumpInterval;

     // the configured dump location
     private File dumpLocation;

     // the actual threshold (configured or dynamically set in the console UI)
     private int threshold;

     // the system time of the last memory snapshot written; initialized so as
     // at least write one dump
     private long nextDumpTime = -1;

     // log service
     private ServiceReference logServiceReference;
     private Object logService;

     MemoryUsageSupport(final BundleContext context)
     {
         this.context = context;

         // register for the log service
         try
         {
             context.addServiceListener(this, "(" + Constants.OBJECTCLASS + "=org.osgi.service.log.LogService)");
             logServiceReference = context.getServiceReference("org.osgi.service.log.LogService");
             if (logServiceReference != null)
             {
                 logService = context.getService(logServiceReference);
             }
         }
         catch (InvalidSyntaxException ise)
         {
             // TODO
         }

         // the default dump location
         String propDumps = context.getProperty(MemoryUsageConstants.PROP_DUMP_LOCATION);
         if (propDumps == null)
         {
             propDumps = "dumps";
         }

         // ensure dump location is an absolute path/location
         File dumps = new File(propDumps);
         if (!dumps.isAbsolute())
         {
             File bundleDumps = context.getDataFile(propDumps);
             if (bundleDumps != null)
             {
                 dumps = bundleDumps;
             }
         }
         this.defaultDumpLocation = dumps.getAbsoluteFile();

         // prepare the dump location
         setDumpLocation(null);

         // register for memory threshold notifications
         NotificationEmitter memEmitter = (NotificationEmitter) getMemory();
         memEmitter.addNotificationListener(this, null, null);

         // set the initial automatic dump threshold
         int defaultThreshold;
         String propThreshold = context.getProperty(MemoryUsageConstants.PROP_DUMP_THRESHOLD);
         if (propThreshold != null)
         {
             try
             {
                 defaultThreshold = Integer.parseInt(propThreshold);
                 setThreshold(defaultThreshold);
             }
             catch (Exception e)
             {
                 // NumberFormatException - if propTreshold cannot be parsed to
                 // int
                 // IllegalArgumentException - if threshold is invalid
                 defaultThreshold = -1;
             }
         }
         else
         {
             defaultThreshold = -1;
         }

         // default threshold has not been configured (correctly), assume fixed
         // default
         if (defaultThreshold < 0)
         {
             defaultThreshold = MemoryUsageConstants.DEFAULT_DUMP_THRESHOLD;
             setThreshold(defaultThreshold);
         }

         this.defaultThreshold = defaultThreshold;

         // set the initial automatic dump threshold
         int interval;
         String propInterval = context.getProperty(MemoryUsageConstants.PROP_DUMP_INTERVAL);
         if (propInterval != null)
         {
             try
             {
                 interval = Integer.parseInt(propInterval);
             }
             catch (Exception e)
             {
                 // NumberFormatException - if propTreshold cannot be parsed to
                 // int
                 // IllegalArgumentException - if threshold is invalid
                 interval = -1;
             }
         }
         else
         {
             interval = -1;
         }
         setInterval(interval);
     }

     void dispose()
     {
         NotificationEmitter memEmitter = (NotificationEmitter) getMemory();
         try
         {
             memEmitter.removeNotificationListener(this);
         }
         catch (ListenerNotFoundException e)
         {
             // don't care
         }

         context.removeServiceListener(this);
         if (logServiceReference != null)
         {
             context.ungetService(logServiceReference);
             logServiceReference = null;
             logService = null;
         }
     }

     public BundleContext getBundleContext()
     {
         return context;
     }

     /**
      * Sets the threshold percentage.
      *
      * @param percentage The threshold as a percentage of memory consumption.
      *            This value may be 0 (zero) to switch off automatic heap dumps
      *            or in the range {@link #MIN_DUMP_THRESHOLD} to
      *            {@link #MAX_DUMP_THRESHOLD}. If set to a negative value,
      *            the default threshold is assumed.
      * @throws IllegalArgumentException if the percentage value is outside of
      *             the valid range of thresholds. The message is the percentage
      *             value which is not accepted.
      */
     final void setThreshold(int percentage)
     {
         if (percentage < 0)
         {
             percentage = defaultThreshold;
         }

         if (MemoryUsageConstants.isThresholdValid(percentage))
         {
             TreeSet<String> thresholdPools = new TreeSet<String>();
             TreeSet<String> noThresholdPools = new TreeSet<String>();
             List<MemoryPoolMXBean> pools = getMemoryPools();
             for (MemoryPoolMXBean pool : pools)
             {
                 if (pool.isUsageThresholdSupported())
                 {
                     long threshold = pool.getUsage().getMax() * percentage / 100;
                     pool.setUsageThreshold(threshold);
                     thresholdPools.add(pool.getName());
                 }
                 else
                 {
                     noThresholdPools.add(pool.getName());
                 }
             }
             this.threshold = percentage;

             log(LogService.LOG_INFO, "Setting Automatic Memory Dump Threshold to %d%% for pools %s", threshold,
                 thresholdPools);
             log(LogService.LOG_INFO, "Automatic Memory Dump cannot be set for pools %s", noThresholdPools);
         }
         else
         {
             throw new IllegalArgumentException(String.valueOf(percentage));
         }
     }

     final int getThreshold()
     {
         return threshold;
     }

     final void setInterval(long interval)
     {
         if (interval < 0)
         {
             interval = MemoryUsageConstants.DEFAULT_DUMP_INTERVAL;
         }
         else
         {
             interval = 1000L * interval;
         }
         this.minDumpInterval = interval;
         log(LogService.LOG_INFO, "Setting Automatic Memory Dump Interval to %d seconds", getInterval());
     }

     final long getInterval()
     {
         return minDumpInterval / 1000L;
     }

     final void printMemory(final PrintHelper pw)
     {
         pw.title("Overall Memory Use", 0);
         pw.keyVal("Heap Dump Threshold", getThreshold() + "%");
         pw.keyVal("Heap Dump Interval", getInterval() + " seconds");
         printOverallMemory(pw);

         pw.title("Memory Pools", 0);
         printMemoryPools(pw);

         pw.title("Heap Dumps", 0);
         listDumpFiles(pw);
     }

     final void printOverallMemory(final PrintHelper pw)
     {
         final MemoryMXBean mem = getMemory();

         pw.keyVal("Verbose Memory Output", (mem.isVerbose() ? "yes" : "no"));
         pw.keyVal("Pending Finalizable Objects", mem.getObjectPendingFinalizationCount());

         pw.keyVal("Overall Heap Memory Usage", mem.getHeapMemoryUsage());
         pw.keyVal("Overall Non-Heap Memory Usage", mem.getNonHeapMemoryUsage());
     }

     final void printMemoryPools(final PrintHelper pw)
     {
         final List<MemoryPoolMXBean> pools = getMemoryPools();
         for (MemoryPoolMXBean pool : pools)
         {
             final String title = String.format("%s (%s, %s)", pool.getName(), pool.getType(), (pool.isValid() ? "valid"
                 : "invalid"));
             pw.title(title, 1);

             pw.keyVal("Memory Managers", Arrays.asList(pool.getMemoryManagerNames()));

             pw.keyVal("Peak Usage", pool.getPeakUsage());

             pw.keyVal("Usage", pool.getUsage());
             if (pool.isUsageThresholdSupported())
             {
                 pw.keyVal("Usage Threshold", String.format("%d, %s, #exceeded=%d", pool.getUsageThreshold(), pool
                     .isUsageThresholdExceeded() ? "exceeded" : "not exceeded", pool.getUsageThresholdCount()));
             }
             else
             {
                 pw.val("Usage Threshold: not supported");
             }
             pw.keyVal("Collection Usage", pool.getCollectionUsage());
             if (pool.isCollectionUsageThresholdSupported())
             {
                 pw.keyVal("Collection Usage Threshold", String.format("%d, %s, #exceeded=%d", pool
                     .getCollectionUsageThreshold(), pool.isCollectionUsageThresholdExceeded() ? "exceeded"
                     : "not exceeded", pool.getCollectionUsageThresholdCount()));
             }
             else
             {
                 pw.val("Collection Usage Threshold: not supported");
             }
         }
     }

     final String getMemoryPoolsJson()
     {
         final StringBuilder buf = new StringBuilder();
         buf.append("[");

         long usedTotal = 0;
         long initTotal = 0;
         long committedTotal = 0;
         long maxTotal = 0;

         final List<MemoryPoolMXBean> pools = getMemoryPools();
         for (MemoryPoolMXBean pool : pools)
         {
             buf.append("{");

             buf.append("'name':'").append(pool.getName().replace("'", "\\'")).append('\'');
             buf.append(",'type':'").append(pool.getType()).append('\'');

             MemoryUsage usage = pool.getUsage();
             final long used = usage.getUsed();
             formatNumber(buf, "used", used);
             if ( used > -1 )
             {
                 usedTotal += used;
             }
             final long init = usage.getInit();
             formatNumber(buf, "init", init);
             if ( init > - 1 )
             {
                 initTotal +=  init;
             }
             final long committed = usage.getCommitted();
             formatNumber(buf, "committed", committed);
             committedTotal += committed;
             final long max = usage.getMax();
             formatNumber(buf, "max", usage.getMax());

             final long score;
             if ( max == -1 || used == -1 )
             {
                 score = 100;
             }
             else
             {
                 maxTotal += max;
                 score = 100L * used / max;
             }
             buf.append(",'score':'").append(score).append("%'");

             buf.append("},");
         }

         // totalisation
         buf.append("{");
         buf.append("'name':'Total','type':'TOTAL'");
         formatNumber(buf, "used", usedTotal);
         formatNumber(buf, "init", initTotal);
         formatNumber(buf, "committed", committedTotal);
         formatNumber(buf, "max", maxTotal);

         final long score = 100L * usedTotal / maxTotal;
         buf.append(",'score':'").append(score).append("%'");

         buf.append("}");

         buf.append("]");
         return buf.toString();
     }

     void formatNumber(final StringBuilder buf, final String title, final long value)
     {

         final BigDecimal KB = new BigDecimal(1000L);
         final BigDecimal MB = new BigDecimal(1000L * 1000);
         final BigDecimal GB = new BigDecimal(1000L * 1000 * 1000);

         BigDecimal bd = new BigDecimal(value);
         final String suffix;
         if (bd.compareTo(GB) > 0)
         {
             bd = bd.divide(GB);
             suffix = "GB";
         }
         else if (bd.compareTo(MB) > 0)
         {
             bd = bd.divide(MB);
             suffix = "MB";
         }
         else if (bd.compareTo(KB) > 0)
         {
             bd = bd.divide(KB);
             suffix = "kB";
         }
         else if (value >= 0 )
         {
             suffix = "B";
         }
         else
         {
             suffix = null;
         }
         buf.append(",'").append(title).append("':'");
         if ( suffix == null )
         {
             buf.append("unknown");
         }
         else
         {
             bd = bd.setScale(2, RoundingMode.UP);
             buf.append(bd).append(suffix);
         }
         buf.append('\'');
     }

     final String getDefaultDumpLocation()
     {
         return defaultDumpLocation.getAbsolutePath();
     }

     final void setDumpLocation(final String dumpLocation)
     {
         if (dumpLocation == null || dumpLocation.length() == 0)
         {
             this.dumpLocation = defaultDumpLocation;
         }
         else
         {
             this.dumpLocation = new File(dumpLocation).getAbsoluteFile();
         }

         log(LogService.LOG_INFO, "Storing Memory Dumps in %s", this.dumpLocation);
     }

     final File getDumpLocation()
     {
         return dumpLocation;
     }

     final void listDumpFiles(final PrintHelper pw)
     {
         pw.title(dumpLocation.getAbsolutePath(), 1);
         File[] dumps = getDumpFiles();
         if (dumps == null || dumps.length == 0)
         {
             pw.keyVal("-- None", null);
         }
         else
         {
             long totalSize = 0;
             for (File dump : dumps)
             {
                 // 32167397 2010-02-25 23:30 thefile
                 pw
                     .val(String.format("%10d %tF %2$tR %s", dump.length(), new Date(dump.lastModified()), dump
                         .getName()));
                 totalSize += dump.length();
             }
             pw.val(String.format("%d files, %d bytes", dumps.length, totalSize));
         }
     }

     final File getDumpFile(final String name)
     {
         // expect a non-empty string without slash
         if (name == null || name.length() == 0 || name.indexOf('/') >= 0)
         {
             return null;
         }

         File dumpFile = new File(dumpLocation, name);
         if (dumpFile.isFile())
         {
             return dumpFile;
         }

         return null;
     }

     final File[] getDumpFiles()
     {
         return dumpLocation.listFiles();
     }

     final boolean rmDumpFile(final String name)
     {
         if (name == null || name.length() == 0)
         {
             return false;
         }

         final File dumpFile = new File(dumpLocation, name);
         if (!dumpFile.exists())
         {
             return false;
         }

         dumpFile.delete();
         return true;
     }

     /**
      * Dumps the heap to a temporary file
      *
      * @param live <code>true</code> if only live objects are to be returned
      * @return
      * @throws NoSuchElementException If no provided mechanism is successfully
      *             used to create a heap dump
      */
     final File dumpHeap(String name, final boolean live)
     {
         // ensure dumplocation exists
         dumpLocation.mkdirs();

         File dump = dumpSunMBean(name, live);
         if (dump == null)
         {
             dump = dumpIbmDump(name);
         }

         if (dump == null)
         {
             throw new NoSuchElementException();
         }

         return dump;
     }

     final MemoryMXBean getMemory()
     {
         return ManagementFactory.getMemoryMXBean();
     }

     final List<MemoryPoolMXBean> getMemoryPools()
     {
         return ManagementFactory.getMemoryPoolMXBeans();
     }

     public void handleNotification(Notification notification, Object handback)
     {
         String notifType = notification.getType();
         if (notifType.equals(MemoryNotificationInfo.MEMORY_THRESHOLD_EXCEEDED))
         {
             if (System.currentTimeMillis() >= nextDumpTime)
             {
                 log(LogService.LOG_WARNING, "Received Memory Threshold Exceeded Notification, dumping Heap");
                 try
                 {
                     File file = dumpHeap(null, true);
                     log(LogService.LOG_WARNING, "Heap dumped to " + file);
                     nextDumpTime = System.currentTimeMillis() + minDumpInterval;
                 }
                 catch (NoSuchElementException e)
                 {
                     log(LogService.LOG_ERROR,
                         "Failed dumping the heap, JVM does not provide known mechanism to create a Heap Dump");
                 }
             }
             else
             {
                 log(LogService.LOG_WARNING,
                     "Ignoring Memory Threshold Exceeded Notification, minimum dump interval since last dump has not passed yet");
             }
         }
     }

     static interface PrintHelper
     {
         void title(final String title, final int level);

         void val(final String value);

         void keyVal(final String key, final Object value);
     }

     // ---------- Various System Specific Heap Dump mechanisms

     /**
      * @see http://blogs.sun.com/sundararajan/entry/
      *      programmatically_dumping_heap_from_java
      */
     private File dumpSunMBean(String name, boolean live)
     {
         if (name == null)
         {
             name = "heap." + System.currentTimeMillis() + ".hprof";
         }

         File tmpFile = new File(dumpLocation, name);
         MBeanServer server = ManagementFactory.getPlatformMBeanServer();

         try
         {
             server.invoke(new ObjectName(HOTSPOT_BEAN_NAME), "dumpHeap", new Object[]
                 { tmpFile.getAbsolutePath(), live }, new String[]
                 { String.class.getName(), boolean.class.getName() });

             log(LogService.LOG_DEBUG, "dumpSunMBean: Dumped Heap to %s using Sun HotSpot MBean", tmpFile);
             return tmpFile;
         }
         catch (Throwable t)
         {
             log(LogService.LOG_DEBUG, "dumpSunMBean: Dump by Sun HotSpot MBean not working", t);
             tmpFile.delete();
         }

         return null;
     }

     /**
      * @param name
      * @return
      * @see <a href="http://publib.boulder.ibm.com/infocenter/javasdk/v5r0/index.jsp?topic=/com.ibm.java.doc.diagnostics.50/diag/tools/heapdump_enable.html">Getting Heapdumps</a>
      */
     private File dumpIbmDump(String name)
     {
         try
         {
             // to try to indicate which file will contain the heap dump
             long minFileTime = System.currentTimeMillis();

             // call the com.ibm.jvm.Dump.HeapDump() method
             Class<?> c = ClassLoader.getSystemClassLoader().loadClass("com.ibm.jvm.Dump");
             Method m = c.getDeclaredMethod("HeapDump", (Class<?>[]) null);
             m.invoke(null, (Object[]) null);

             // find the file in the current working directory
             File dir = new File("").getAbsoluteFile();
             File[] files = dir.listFiles();
             if (files != null)
             {
                 for (File file : files)
                 {
                     if (file.isFile() && file.lastModified() > minFileTime)
                     {
                         if (name == null)
                         {
                             name = file.getName();
                         }
                         File target = new File(dumpLocation, name);
                         file.renameTo(target);

                         log(LogService.LOG_DEBUG, "dumpSunMBean: Dumped Heap to %s using IBM Dump.HeapDump()", target);
                         return target;
                     }
                 }

                 log(LogService.LOG_DEBUG, "dumpIbmDump: None of %d files '%s' is younger than %d", files.length, dir,
                     minFileTime);
             }
             else
             {
                 log(LogService.LOG_DEBUG, "dumpIbmDump: Hmm '%s' does not seem to be a directory; isdir=%b ??", dir,
                     dir.isDirectory());
             }

             log(LogService.LOG_WARNING, "dumpIbmDump: Heap Dump has been created but cannot be located");
             return dumpLocation;
         }
         catch (Throwable t)
         {
             log(LogService.LOG_DEBUG, "dumpIbmDump: Dump by IBM Dump class not working", t);
         }

         return null;
     }

     // ---------- Logging support

     public void serviceChanged(ServiceEvent event)
     {
         if (event.getType() == ServiceEvent.REGISTERED && logServiceReference == null)
         {
             logServiceReference = event.getServiceReference();
             logService = context.getService(event.getServiceReference());
         }
         else if (event.getType() == ServiceEvent.UNREGISTERING && logServiceReference == event.getServiceReference())
         {
             logServiceReference = null;
             logService = null;
             context.ungetService(event.getServiceReference());
         }
     }

     void log(int level, String format, Object... args)
     {
         log(level, null, format, args);
     }

     void log(int level, Throwable t, String format, Object... args)
     {
         Object logService = this.logService;
         final String message = String.format(format, args);
         if (logService != null)
         {
             try {
                 Method m = logService.getClass()
                         .getDeclaredMethod("log", int.class, String.class, Throwable.class);
                 m.setAccessible(true);
                 m.invoke(logService, level, message, t);
             } catch (Exception e) {
                 logSTD(LogService.LOG_WARNING, e, "Unable to log with the given log service");
                 logSTD(level, t, message);
             }
         }
         else
         {
             logSTD(level, t, message);
         }
     }

     private void logSTD(int level, Throwable t, String message) {
         PrintStream out = (level <= LogService.LOG_ERROR) ? System.err : System.out;
         out.printf("%s: %s (%d): %s%n", toLevelString(level), context.getBundle().getSymbolicName(), context
             .getBundle().getBundleId(), message);
         if (t != null)
         {
             t.printStackTrace(out);
         }
     }

     private String toLevelString(int level)
     {
         switch (level)
         {
             case LogService.LOG_DEBUG:
                 return "DEBUG";
             case LogService.LOG_INFO:
                 return "INFO ";
             case LogService.LOG_WARNING:
                 return "WARN ";
             case LogService.LOG_ERROR:
                 return "ERROR";
             default:
                 return "unknown(" + level + ")";
         }
     }
 }
	/*
	* 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.felix.webconsole.plugins.memoryusage.internal;

	import java.io.File;
	import java.io.PrintStream;
	import java.lang.management.ManagementFactory;
	import java.lang.management.MemoryMXBean;
	import java.lang.management.MemoryNotificationInfo;
	import java.lang.management.MemoryPoolMXBean;
	import java.lang.management.MemoryUsage;
	import java.lang.reflect.Method;
	import java.math.BigDecimal;
	import java.math.RoundingMode;
	import java.util.Arrays;
	import java.util.Date;
	import java.util.List;
	import java.util.NoSuchElementException;
	import java.util.TreeSet;

	import javax.management.ListenerNotFoundException;
	import javax.management.MBeanServer;
	import javax.management.Notification;
	import javax.management.NotificationEmitter;
	import javax.management.NotificationListener;
	import javax.management.ObjectName;

	import org.osgi.framework.BundleContext;
	import org.osgi.framework.Constants;
	import org.osgi.framework.InvalidSyntaxException;
	import org.osgi.framework.ServiceEvent;
	import org.osgi.framework.ServiceListener;
	import org.osgi.framework.ServiceReference;
	import org.osgi.service.log.LogService;

	final class MemoryUsageSupport implements NotificationListener, ServiceListener
	{

	// This is the name of the HotSpot Diagnostic MBean
	private static final String HOTSPOT_BEAN_NAME = "com.sun.management:type=HotSpotDiagnostic";

	// to get the LogService
	private final BundleContext context;

	// the default dump location: the dumps folder in the bundle private data
	// or the current working directory
	private final File defaultDumpLocation;

	// the default threshold value
	private final int defaultThreshold;

	// the minimum number of milliseconds between two consecutive memory
	// dumps written. this setting allows limitting the generation of memory
	// dumps if memory consumption is oscillating around the memory
	// threshold value
	private long minDumpInterval;

	// the configured dump location
	private File dumpLocation;

	// the actual threshold (configured or dynamically set in the console UI)
	private int threshold;

	// the system time of the last memory snapshot written; initialized so as
	// at least write one dump
	private long nextDumpTime = -1;

	// log service
	private ServiceReference logServiceReference;
	private Object logService;

	MemoryUsageSupport(final BundleContext context)
	{
	this.context = context;

	// register for the log service
	try
	{
	context.addServiceListener(this, "(" + Constants.OBJECTCLASS + "=org.osgi.service.log.LogService)");
	logServiceReference = context.getServiceReference("org.osgi.service.log.LogService");
	if (logServiceReference != null)
	{
	logService = context.getService(logServiceReference);
	}
	}
	catch (InvalidSyntaxException ise)
	{
	// TODO
	}

	// the default dump location
	String propDumps = context.getProperty(MemoryUsageConstants.PROP_DUMP_LOCATION);
	if (propDumps == null)
	{
	propDumps = "dumps";
	}

	// ensure dump location is an absolute path/location
	File dumps = new File(propDumps);
	if (!dumps.isAbsolute())
	{
	File bundleDumps = context.getDataFile(propDumps);
	if (bundleDumps != null)
	{
	dumps = bundleDumps;
	}
	}
	this.defaultDumpLocation = dumps.getAbsoluteFile();

	// prepare the dump location
	setDumpLocation(null);

	// register for memory threshold notifications
	NotificationEmitter memEmitter = (NotificationEmitter) getMemory();
	memEmitter.addNotificationListener(this, null, null);

	// set the initial automatic dump threshold
	int defaultThreshold;
	String propThreshold = context.getProperty(MemoryUsageConstants.PROP_DUMP_THRESHOLD);
	if (propThreshold != null)
	{
	try
	{
	defaultThreshold = Integer.parseInt(propThreshold);
	setThreshold(defaultThreshold);
	}
	catch (Exception e)
	{
	// NumberFormatException - if propTreshold cannot be parsed to
	// int
	// IllegalArgumentException - if threshold is invalid
	defaultThreshold = -1;
	}
	}
	else
	{
	defaultThreshold = -1;
	}

	// default threshold has not been configured (correctly), assume fixed
	// default
	if (defaultThreshold < 0)
	{
	defaultThreshold = MemoryUsageConstants.DEFAULT_DUMP_THRESHOLD;
	setThreshold(defaultThreshold);
	}

	this.defaultThreshold = defaultThreshold;

	// set the initial automatic dump threshold
	int interval;
	String propInterval = context.getProperty(MemoryUsageConstants.PROP_DUMP_INTERVAL);
	if (propInterval != null)
	{
	try
	{
	interval = Integer.parseInt(propInterval);
	}
	catch (Exception e)
	{
	// NumberFormatException - if propTreshold cannot be parsed to
	// int
	// IllegalArgumentException - if threshold is invalid
	interval = -1;
	}
	}
	else
	{
	interval = -1;
	}
	setInterval(interval);
	}

	void dispose()
	{
	NotificationEmitter memEmitter = (NotificationEmitter) getMemory();
	try
	{
	memEmitter.removeNotificationListener(this);
	}
	catch (ListenerNotFoundException e)
	{
	// don't care
	}

	context.removeServiceListener(this);
	if (logServiceReference != null)
	{
	context.ungetService(logServiceReference);
	logServiceReference = null;
	logService = null;
	}
	}

	public BundleContext getBundleContext()
	{
	return context;
	}

	/**
	* Sets the threshold percentage.
	*
	* @param percentage The threshold as a percentage of memory consumption.
	* This value may be 0 (zero) to switch off automatic heap dumps
	* or in the range {@link #MIN_DUMP_THRESHOLD} to
	* {@link #MAX_DUMP_THRESHOLD}. If set to a negative value,
	* the default threshold is assumed.
	* @throws IllegalArgumentException if the percentage value is outside of
	* the valid range of thresholds. The message is the percentage
	* value which is not accepted.
	*/
	final void setThreshold(int percentage)
	{
	if (percentage < 0)
	{
	percentage = defaultThreshold;
	}

	if (MemoryUsageConstants.isThresholdValid(percentage))
	{
	TreeSet<String> thresholdPools = new TreeSet<String>();
	TreeSet<String> noThresholdPools = new TreeSet<String>();
	List<MemoryPoolMXBean> pools = getMemoryPools();
	for (MemoryPoolMXBean pool : pools)
	{
	if (pool.isUsageThresholdSupported())
	{
	long threshold = pool.getUsage().getMax() * percentage / 100;
	pool.setUsageThreshold(threshold);
	thresholdPools.add(pool.getName());
	}
	else
	{
	noThresholdPools.add(pool.getName());
	}
	}
	this.threshold = percentage;

	log(LogService.LOG_INFO, "Setting Automatic Memory Dump Threshold to %d%% for pools %s", threshold,
	thresholdPools);
	log(LogService.LOG_INFO, "Automatic Memory Dump cannot be set for pools %s", noThresholdPools);
	}
	else
	{
	throw new IllegalArgumentException(String.valueOf(percentage));
	}
	}

	final int getThreshold()
	{
	return threshold;
	}

	final void setInterval(long interval)
	{
	if (interval < 0)
	{
	interval = MemoryUsageConstants.DEFAULT_DUMP_INTERVAL;
	}
	else
	{
	interval = 1000L * interval;
	}
	this.minDumpInterval = interval;
	log(LogService.LOG_INFO, "Setting Automatic Memory Dump Interval to %d seconds", getInterval());
	}

	final long getInterval()
	{
	return minDumpInterval / 1000L;
	}

	final void printMemory(final PrintHelper pw)
	{
	pw.title("Overall Memory Use", 0);
	pw.keyVal("Heap Dump Threshold", getThreshold() + "%");
	pw.keyVal("Heap Dump Interval", getInterval() + " seconds");
	printOverallMemory(pw);

	pw.title("Memory Pools", 0);
	printMemoryPools(pw);

	pw.title("Heap Dumps", 0);
	listDumpFiles(pw);
	}

	final void printOverallMemory(final PrintHelper pw)
	{
	final MemoryMXBean mem = getMemory();

	pw.keyVal("Verbose Memory Output", (mem.isVerbose() ? "yes" : "no"));
	pw.keyVal("Pending Finalizable Objects", mem.getObjectPendingFinalizationCount());

	pw.keyVal("Overall Heap Memory Usage", mem.getHeapMemoryUsage());
	pw.keyVal("Overall Non-Heap Memory Usage", mem.getNonHeapMemoryUsage());
	}

	final void printMemoryPools(final PrintHelper pw)
	{
	final List<MemoryPoolMXBean> pools = getMemoryPools();
	for (MemoryPoolMXBean pool : pools)
	{
	final String title = String.format("%s (%s, %s)", pool.getName(), pool.getType(), (pool.isValid() ? "valid"
	: "invalid"));
	pw.title(title, 1);

	pw.keyVal("Memory Managers", Arrays.asList(pool.getMemoryManagerNames()));

	pw.keyVal("Peak Usage", pool.getPeakUsage());

	pw.keyVal("Usage", pool.getUsage());
	if (pool.isUsageThresholdSupported())
	{
	pw.keyVal("Usage Threshold", String.format("%d, %s, #exceeded=%d", pool.getUsageThreshold(), pool
	.isUsageThresholdExceeded() ? "exceeded" : "not exceeded", pool.getUsageThresholdCount()));
	}
	else
	{
	pw.val("Usage Threshold: not supported");
	}
	pw.keyVal("Collection Usage", pool.getCollectionUsage());
	if (pool.isCollectionUsageThresholdSupported())
	{
	pw.keyVal("Collection Usage Threshold", String.format("%d, %s, #exceeded=%d", pool
	.getCollectionUsageThreshold(), pool.isCollectionUsageThresholdExceeded() ? "exceeded"
	: "not exceeded", pool.getCollectionUsageThresholdCount()));
	}
	else
	{
	pw.val("Collection Usage Threshold: not supported");
	}
	}
	}

	final String getMemoryPoolsJson()
	{
	final StringBuilder buf = new StringBuilder();
	buf.append("[");

	long usedTotal = 0;
	long initTotal = 0;
	long committedTotal = 0;
	long maxTotal = 0;

	final List<MemoryPoolMXBean> pools = getMemoryPools();
	for (MemoryPoolMXBean pool : pools)
	{
	buf.append("{");

	buf.append("'name':'").append(pool.getName().replace("'", "\\'")).append('\'');
	buf.append(",'type':'").append(pool.getType()).append('\'');

	MemoryUsage usage = pool.getUsage();
	final long used = usage.getUsed();
	formatNumber(buf, "used", used);
	if ( used > -1 )
	{
	usedTotal += used;
	}
	final long init = usage.getInit();
	formatNumber(buf, "init", init);
	if ( init > - 1 )
	{
	initTotal += init;
	}
	final long committed = usage.getCommitted();
	formatNumber(buf, "committed", committed);
	committedTotal += committed;
	final long max = usage.getMax();
	formatNumber(buf, "max", usage.getMax());

	final long score;
	if ( max == -1 \|\| used == -1 )
	{
	score = 100;
	}
	else
	{
	maxTotal += max;
	score = 100L * used / max;
	}
	buf.append(",'score':'").append(score).append("%'");

	buf.append("},");
	}

	// totalisation
	buf.append("{");
	buf.append("'name':'Total','type':'TOTAL'");
	formatNumber(buf, "used", usedTotal);
	formatNumber(buf, "init", initTotal);
	formatNumber(buf, "committed", committedTotal);
	formatNumber(buf, "max", maxTotal);

	final long score = 100L * usedTotal / maxTotal;
	buf.append(",'score':'").append(score).append("%'");

	buf.append("}");

	buf.append("]");
	return buf.toString();
	}

	void formatNumber(final StringBuilder buf, final String title, final long value)
	{

	final BigDecimal KB = new BigDecimal(1000L);
	final BigDecimal MB = new BigDecimal(1000L * 1000);
	final BigDecimal GB = new BigDecimal(1000L * 1000 * 1000);

	BigDecimal bd = new BigDecimal(value);
	final String suffix;
	if (bd.compareTo(GB) > 0)
	{
	bd = bd.divide(GB);
	suffix = "GB";
	}
	else if (bd.compareTo(MB) > 0)
	{
	bd = bd.divide(MB);
	suffix = "MB";
	}
	else if (bd.compareTo(KB) > 0)
	{
	bd = bd.divide(KB);
	suffix = "kB";
	}
	else if (value >= 0 )
	{
	suffix = "B";
	}
	else
	{
	suffix = null;
	}
	buf.append(",'").append(title).append("':'");
	if ( suffix == null )
	{
	buf.append("unknown");
	}
	else
	{
	bd = bd.setScale(2, RoundingMode.UP);
	buf.append(bd).append(suffix);
	}
	buf.append('\'');
	}

	final String getDefaultDumpLocation()
	{
	return defaultDumpLocation.getAbsolutePath();
	}

	final void setDumpLocation(final String dumpLocation)
	{
	if (dumpLocation == null \|\| dumpLocation.length() == 0)
	{
	this.dumpLocation = defaultDumpLocation;
	}
	else
	{
	this.dumpLocation = new File(dumpLocation).getAbsoluteFile();
	}

	log(LogService.LOG_INFO, "Storing Memory Dumps in %s", this.dumpLocation);
	}

	final File getDumpLocation()
	{
	return dumpLocation;
	}

	final void listDumpFiles(final PrintHelper pw)
	{
	pw.title(dumpLocation.getAbsolutePath(), 1);
	File[] dumps = getDumpFiles();
	if (dumps == null \|\| dumps.length == 0)
	{
	pw.keyVal("-- None", null);
	}
	else
	{
	long totalSize = 0;
	for (File dump : dumps)
	{
	// 32167397 2010-02-25 23:30 thefile
	pw
	.val(String.format("%10d %tF %2$tR %s", dump.length(), new Date(dump.lastModified()), dump
	.getName()));
	totalSize += dump.length();
	}
	pw.val(String.format("%d files, %d bytes", dumps.length, totalSize));
	}
	}

	final File getDumpFile(final String name)
	{
	// expect a non-empty string without slash
	if (name == null \|\| name.length() == 0 \|\| name.indexOf('/') >= 0)
	{
	return null;
	}

	File dumpFile = new File(dumpLocation, name);
	if (dumpFile.isFile())
	{
	return dumpFile;
	}

	return null;
	}

	final File[] getDumpFiles()
	{
	return dumpLocation.listFiles();
	}

	final boolean rmDumpFile(final String name)
	{
	if (name == null \|\| name.length() == 0)
	{
	return false;
	}

	final File dumpFile = new File(dumpLocation, name);
	if (!dumpFile.exists())
	{
	return false;
	}

	dumpFile.delete();
	return true;
	}

	/**
	* Dumps the heap to a temporary file
	*
	* @param live <code>true</code> if only live objects are to be returned
	* @return
	* @throws NoSuchElementException If no provided mechanism is successfully
	* used to create a heap dump
	*/
	final File dumpHeap(String name, final boolean live)
	{
	// ensure dumplocation exists
	dumpLocation.mkdirs();

	File dump = dumpSunMBean(name, live);
	if (dump == null)
	{
	dump = dumpIbmDump(name);
	}

	if (dump == null)
	{
	throw new NoSuchElementException();
	}

	return dump;
	}

	final MemoryMXBean getMemory()
	{
	return ManagementFactory.getMemoryMXBean();
	}

	final List<MemoryPoolMXBean> getMemoryPools()
	{
	return ManagementFactory.getMemoryPoolMXBeans();
	}

	public void handleNotification(Notification notification, Object handback)
	{
	String notifType = notification.getType();
	if (notifType.equals(MemoryNotificationInfo.MEMORY_THRESHOLD_EXCEEDED))
	{
	if (System.currentTimeMillis() >= nextDumpTime)
	{
	log(LogService.LOG_WARNING, "Received Memory Threshold Exceeded Notification, dumping Heap");
	try
	{
	File file = dumpHeap(null, true);
	log(LogService.LOG_WARNING, "Heap dumped to " + file);
	nextDumpTime = System.currentTimeMillis() + minDumpInterval;
	}
	catch (NoSuchElementException e)
	{
	log(LogService.LOG_ERROR,
	"Failed dumping the heap, JVM does not provide known mechanism to create a Heap Dump");
	}
	}
	else
	{
	log(LogService.LOG_WARNING,
	"Ignoring Memory Threshold Exceeded Notification, minimum dump interval since last dump has not passed yet");
	}
	}
	}

	static interface PrintHelper
	{
	void title(final String title, final int level);

	void val(final String value);

	void keyVal(final String key, final Object value);
	}

	// ---------- Various System Specific Heap Dump mechanisms

	/**
	* @see http://blogs.sun.com/sundararajan/entry/
	* programmatically_dumping_heap_from_java
	*/
	private File dumpSunMBean(String name, boolean live)
	{
	if (name == null)
	{
	name = "heap." + System.currentTimeMillis() + ".hprof";
	}

	File tmpFile = new File(dumpLocation, name);
	MBeanServer server = ManagementFactory.getPlatformMBeanServer();

	try
	{
	server.invoke(new ObjectName(HOTSPOT_BEAN_NAME), "dumpHeap", new Object[]
	{ tmpFile.getAbsolutePath(), live }, new String[]
	{ String.class.getName(), boolean.class.getName() });

	log(LogService.LOG_DEBUG, "dumpSunMBean: Dumped Heap to %s using Sun HotSpot MBean", tmpFile);
	return tmpFile;
	}
	catch (Throwable t)
	{
	log(LogService.LOG_DEBUG, "dumpSunMBean: Dump by Sun HotSpot MBean not working", t);
	tmpFile.delete();
	}

	return null;
	}

	/**
	* @param name
	* @return
	* @see <a href="http://publib.boulder.ibm.com/infocenter/javasdk/v5r0/index.jsp?topic=/com.ibm.java.doc.diagnostics.50/diag/tools/heapdump_enable.html">Getting Heapdumps</a>
	*/
	private File dumpIbmDump(String name)
	{
	try
	{
	// to try to indicate which file will contain the heap dump
	long minFileTime = System.currentTimeMillis();

	// call the com.ibm.jvm.Dump.HeapDump() method
	Class<?> c = ClassLoader.getSystemClassLoader().loadClass("com.ibm.jvm.Dump");
	Method m = c.getDeclaredMethod("HeapDump", (Class<?>[]) null);
	m.invoke(null, (Object[]) null);

	// find the file in the current working directory
	File dir = new File("").getAbsoluteFile();
	File[] files = dir.listFiles();
	if (files != null)
	{
	for (File file : files)
	{
	if (file.isFile() && file.lastModified() > minFileTime)
	{
	if (name == null)
	{
	name = file.getName();
	}
	File target = new File(dumpLocation, name);
	file.renameTo(target);

	log(LogService.LOG_DEBUG, "dumpSunMBean: Dumped Heap to %s using IBM Dump.HeapDump()", target);
	return target;
	}
	}

	log(LogService.LOG_DEBUG, "dumpIbmDump: None of %d files '%s' is younger than %d", files.length, dir,
	minFileTime);
	}
	else
	{
	log(LogService.LOG_DEBUG, "dumpIbmDump: Hmm '%s' does not seem to be a directory; isdir=%b ??", dir,
	dir.isDirectory());
	}

	log(LogService.LOG_WARNING, "dumpIbmDump: Heap Dump has been created but cannot be located");
	return dumpLocation;
	}
	catch (Throwable t)
	{
	log(LogService.LOG_DEBUG, "dumpIbmDump: Dump by IBM Dump class not working", t);
	}

	return null;
	}

	// ---------- Logging support

	public void serviceChanged(ServiceEvent event)
	{
	if (event.getType() == ServiceEvent.REGISTERED && logServiceReference == null)
	{
	logServiceReference = event.getServiceReference();
	logService = context.getService(event.getServiceReference());
	}
	else if (event.getType() == ServiceEvent.UNREGISTERING && logServiceReference == event.getServiceReference())
	{
	logServiceReference = null;
	logService = null;
	context.ungetService(event.getServiceReference());
	}
	}

	void log(int level, String format, Object... args)
	{
	log(level, null, format, args);
	}

	void log(int level, Throwable t, String format, Object... args)
	{
	Object logService = this.logService;
	final String message = String.format(format, args);
	if (logService != null)
	{
	try {
	Method m = logService.getClass()
	.getDeclaredMethod("log", int.class, String.class, Throwable.class);
	m.setAccessible(true);
	m.invoke(logService, level, message, t);
	} catch (Exception e) {
	logSTD(LogService.LOG_WARNING, e, "Unable to log with the given log service");
	logSTD(level, t, message);
	}
	}
	else
	{
	logSTD(level, t, message);
	}
	}

	private void logSTD(int level, Throwable t, String message) {
	PrintStream out = (level <= LogService.LOG_ERROR) ? System.err : System.out;
	out.printf("%s: %s (%d): %s%n", toLevelString(level), context.getBundle().getSymbolicName(), context
	.getBundle().getBundleId(), message);
	if (t != null)
	{
	t.printStackTrace(out);
	}
	}

	private String toLevelString(int level)
	{
	switch (level)
	{
	case LogService.LOG_DEBUG:
	return "DEBUG";
	case LogService.LOG_INFO:
	return "INFO ";
	case LogService.LOG_WARNING:
	return "WARN ";
	case LogService.LOG_ERROR:
	return "ERROR";
	default:
	return "unknown(" + level + ")";
	}
	}
	}