User: simone
Date: 00/12/12 01:45:32
Modified: src/main/org/jboss/ejb/plugins
LRUEnterpriseContextCachePolicy.java
Log:
Removed unnecessary synchronization and improved the necessary one.
Added (remarked) useful debug code.
Improved logging.
Revision Changes Path
1.5 +106 -16
jboss/src/main/org/jboss/ejb/plugins/LRUEnterpriseContextCachePolicy.java
Index: LRUEnterpriseContextCachePolicy.java
===================================================================
RCS file:
/products/cvs/ejboss/jboss/src/main/org/jboss/ejb/plugins/LRUEnterpriseContextCachePolicy.java,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -r1.4 -r1.5
--- LRUEnterpriseContextCachePolicy.java 2000/12/07 15:44:24 1.4
+++ LRUEnterpriseContextCachePolicy.java 2000/12/12 09:45:32 1.5
@@ -20,7 +20,7 @@
*
* @see EnterpriseInstanceCache
* @author Simone Bordet ([EMAIL PROTECTED])
- * @version $Revision: 1.4 $
+ * @version $Revision: 1.5 $
*/
public class LRUEnterpriseContextCachePolicy extends LRUCachePolicy
implements EnterpriseContextCachePolicy, XmlLoadable
@@ -29,7 +29,7 @@
// Attributes ----------------------------------------------------
/* The EnterpriseInstanceCache that uses this cache policy */
- private EnterpriseInstanceCache m_cache;
+ private AbstractInstanceCache m_cache;
/* The period of the resizer's runs */
private long m_resizerPeriod;
/* The period of the overager's runs */
@@ -56,7 +56,7 @@
* Creates a LRU cache policy object given the instance cache that use
* this policy object.
*/
- public LRUEnterpriseContextCachePolicy(EnterpriseInstanceCache eic)
+ public LRUEnterpriseContextCachePolicy(AbstractInstanceCache eic)
{
if (eic == null) throw new IllegalArgumentException("Instance cache
argument cannot be null");
m_cache = eic;
@@ -78,6 +78,9 @@
m_overager = new OveragerTask(m_overagerPeriod);
scheduler.schedule(m_overager, (long)(Math.random() *
m_overagerPeriod));
}
+
+ // TimerTask used only to debug
+// scheduler.schedule(new CacheDumper(), 3000L);
}
public void stop()
@@ -176,19 +179,26 @@
protected void ageOut(LRUCacheEntry entry)
{
if (entry == null) {throw new IllegalArgumentException("Cannot remove
a null cache entry");}
+
+ // Logger is very time expensive. Turn on only for debug
+// log.debug("Aging out from cache bean " +
m_cache.getContainer().getBeanMetaData().getEjbName() + ", id = " + entry.m_key + ";
cache size = " + getList().m_count);
+ // Debug code
+// new Exception().printStackTrace();
+// new CacheDumper().execute();
+
+ // This will schedule the passivation
m_cache.release((EnterpriseContext)entry.m_object);
}
protected void cacheMiss()
{
ContextLRUList list = getList();
- synchronized (list)
- {
- ++list.m_cacheMiss;
- }
+ ++list.m_cacheMiss;
}
// Private -------------------------------------------------------
private ContextLRUList getList() {return (ContextLRUList)m_list;}
+ // For debug purposes
+// private java.util.Map getMap() {return m_map;}
// Inner classes -------------------------------------------------
/**
@@ -200,16 +210,23 @@
*/
protected class ResizerTask extends TimerTask
{
+ private String m_message;
+ private StringBuffer m_buffer;
+
protected ResizerTask(long resizerPeriod)
{
super(resizerPeriod);
+ m_message = "Resized cache for bean " +
m_cache.getContainer().getBeanMetaData().getEjbName() + ": old size = ";
+ m_buffer = new StringBuffer();
}
public void execute()
{
// For now implemented as a Cache Miss Frequency algorithm
- // Sync the list, since it is accessed also by another thread
+
ContextLRUList list = getList();
- synchronized (list)
+
+ // Sync with the cache, since it is accessed also by another
thread
+ synchronized (m_cache.getCacheLock())
{
int period = list.m_cacheMiss == 0 ? Integer.MAX_VALUE
: (int)(getPeriod() / list.m_cacheMiss);
int cap = list.m_capacity;
@@ -220,7 +237,7 @@
double factor = 1.0 + ((double)m_minPeriod /
period) * (1.0 - m_factor);
int newCap = (int)(cap * factor);
list.m_capacity = newCap < list.m_maxCapacity
? newCap : list.m_maxCapacity;
- log.log("Resized cache for bean " +
m_cache.getContainer().getBeanMetaData().getEjbName() + ": old size = " + cap + ", new
size = " + list.m_capacity);
+ log(cap, list.m_capacity);
}
else if (period >= m_maxPeriod &&
cap > list.m_minCapacity &&
@@ -229,39 +246,75 @@
// Shrink cache capacity
int newCap = (int)(list.m_count / m_factor);
list.m_capacity = newCap > list.m_minCapacity
? newCap : list.m_minCapacity;
- log.log("Resized cache for bean " +
m_cache.getContainer().getBeanMetaData().getEjbName() + ": old size = " + cap + ", new
size = " + list.m_capacity);
+ log(cap, list.m_capacity);
}
list.m_cacheMiss = 0;
}
}
+ private void log(int oldSize, int newSize)
+ {
+ m_buffer.setLength(0);
+ m_buffer.append(m_message);
+ m_buffer.append(oldSize);
+ m_buffer.append(", new size = ");
+ m_buffer.append(newSize);
+ log.debug(m_buffer.toString());
+ }
}
/**
* This TimerTask passivates cached beans that have not been called for a
while.
*/
protected class OveragerTask extends TimerTask
{
+ private String m_message;
+ private StringBuffer m_buffer;
+
protected OveragerTask(long period)
{
super(period);
+ m_message = "Scheduling for passivation overaged bean " +
m_cache.getContainer().getBeanMetaData().getEjbName() + " with id = ";
+ m_buffer = new StringBuffer();
}
public void execute()
{
- ContextLRUEntry entry = null;
- long now = System.currentTimeMillis();
ContextLRUList list = getList();
- synchronized (list)
+ long now = System.currentTimeMillis();
+
+ synchronized (m_cache.getCacheLock())
{
- while ((entry = (ContextLRUEntry)list.m_tail) != null)
+ for (ContextLRUEntry entry =
(ContextLRUEntry)list.m_tail; entry != null; entry = (ContextLRUEntry)list.m_tail)
{
if (now - entry.m_time >= m_maxBeanAge)
{
- log.log("Passivated overaged bean " +
m_cache.getContainer().getBeanMetaData().getEjbName() + " with id = " + entry.m_key);
+ int initialSize = list.m_count;
+
+ // Log informations
+ log(entry.m_key, initialSize);
+
+ // Kick off the cache this entry
ageOut(entry);
+
+ int finalSize = list.m_count;
+
+ if (initialSize == finalSize)
+ {
+ // Here is a bug.
+ throw new
IllegalStateException("Cache synchronization bug");
+ }
}
else {break;}
}
}
}
+ private void log(Object key, int count)
+ {
+ m_buffer.setLength(0);
+ m_buffer.append(m_message);
+ m_buffer.append(key);
+ m_buffer.append(" - Cache size = ");
+ m_buffer.append(count);
+ log.debug(m_buffer.toString());
+ }
}
/* Dummy subclass to give visibility to the inner classes */
protected class ContextLRUList extends LRUList {}
@@ -270,4 +323,41 @@
{
protected ContextLRUEntry(Object key, Object value) {super(key,
value);}
}
+
+ /**
+ * Class used only for debug purposes.
+ */
+/*
+ private class CacheDumper extends TimerTask
+ {
+ private java.io.BufferedReader reader = new java.io.BufferedReader(new
java.io.InputStreamReader(System.in));
+ private CacheDumper() {super(5000L);}
+ public void execute()
+ {
+ synchronized (m_cache.getCacheLock())
+ {
+ if (getMap().size() > 0 && getList().m_count > 0)
+ {
+ System.err.println();
+ System.err.println("DUMPING CACHE FOR BEAN " +
m_cache.getContainer().getBeanMetaData().getEjbName());
+ System.err.println("THE MAP:");
+
System.err.println(Integer.toHexString(getMap().hashCode()) + " size: " +
getMap().size());
+ for (java.util.Iterator i =
getMap().values().iterator(); i.hasNext();)
+ {
+ System.err.println(i.next());
+ }
+ System.err.println("THE LIST:");
+ System.err.println(getList());
+// readLine();
+ }
+ }
+ }
+ private void readLine()
+ {
+ System.err.println("Hit a key...");
+ try {reader.readLine();}
+ catch (java.io.IOException x) {}
+ }
+ }
+*/
}
