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From ju...@apache.org
Subject svn commit: r1025995 - in /jackrabbit/branches/2.1: ./ jackrabbit-core/src/main/java/org/apache/jackrabbit/core/cache/ jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/ jackrabbit-core/src/main/java/org/apache/jackrabbit/core...
Date Thu, 21 Oct 2010 13:42:18 GMT
Author: jukka
Date: Thu Oct 21 13:42:18 2010
New Revision: 1025995

URL: http://svn.apache.org/viewvc?rev=1025995&view=rev
Log:
2.1: Merged revisions 1004184, 1004223 and 1004223 (JCR-2699)

Modified:
    jackrabbit/branches/2.1/   (props changed)
    jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/cache/ConcurrentCache.java
    jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/AbstractBundlePersistenceManager.java
    jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/BundleDbPersistenceManager.java
    jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/BundleFsPersistenceManager.java
    jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/AbstractBundlePersistenceManager.java
    jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/BundleDbPersistenceManager.java
    jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/BundleFsPersistenceManager.java
    jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/PostgreSQLPersistenceManager.java
    jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/ItemStateReferenceCache.java
    jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/LocalItemStateManager.java
    jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/SharedItemStateManager.java

Propchange: jackrabbit/branches/2.1/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Thu Oct 21 13:42:18 2010
@@ -2,4 +2,4 @@
 /jackrabbit/sandbox/JCR-1456:774917-886178
 /jackrabbit/sandbox/JCR-2170:812417-816332
 /jackrabbit/sandbox/tripod-JCR-2209:795441-795863
-/jackrabbit/trunk:931121,931479,931483-931484,931504,931609,931613,931838,931919,932318-932319,933144,933197,933203,933213,933216,933554,933646,933694,934405,934412,934849,935557,936668,938099,945528,950440,950680,955222,955229,955307,955852,961487,961626,964362,965539,986682,986686,986715,991144,996810,1001707,1002065-1002066,1002084,1002101-1002102,1002168,1002170,1002589,1002608,1002657,1002729,1003423,1003470,1003542,1003773,1004182
+/jackrabbit/trunk:931121,931479,931483-931484,931504,931609,931613,931838,931919,932318-932319,933144,933197,933203,933213,933216,933554,933646,933694,934405,934412,934849,935557,936668,938099,945528,950440,950680,955222,955229,955307,955852,961487,961626,964362,965539,986682,986686,986715,991144,996810,1001707,1002065-1002066,1002084,1002101-1002102,1002168,1002170,1002589,1002608,1002657,1002729,1003423,1003470,1003542,1003773,1004182,1004184,1004223-1004224

Modified: jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/cache/ConcurrentCache.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/cache/ConcurrentCache.java?rev=1025995&r1=1025994&r2=1025995&view=diff
==============================================================================
--- jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/cache/ConcurrentCache.java
(original)
+++ jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/cache/ConcurrentCache.java
Thu Oct 21 13:42:18 2010
@@ -22,9 +22,6 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 /**
  * Concurrent cache implementation that uses cache segments to minimize
  * the chance of lock contention. The LRU algorithm is used to evict excess
@@ -34,9 +31,6 @@ import org.slf4j.LoggerFactory;
  */
 public class ConcurrentCache<K, V> extends AbstractCache {
 
-    /** Logger instance */
-    private static Logger log = LoggerFactory.getLogger(ConcurrentCache.class);
-
     private static class E<V> {
 
         private final V value;
@@ -150,16 +144,18 @@ public class ConcurrentCache<K, V> exten
      * @param key entry key
      * @param value entry value
      * @param size entry size
+     * @return the previous value, or <code>null</code>
      */
-    public void put(K key, V value, long size) {
+    public V put(K key, V value, long size) {
         Map<K, E<V>> segment = getSegment(key);
         synchronized (segment) {
             recordSizeChange(size);
             E<V> previous = segment.put(key, new E<V>(value, size));
             if (previous != null) {
-                log.warn("Overwriting cached entry {} from {} to {}",
-                        new Object[] { key, previous.value, value });
                 recordSizeChange(-previous.size);
+                return previous.value;
+            } else {
+                return null;
             }
         }
     }

Modified: jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/AbstractBundlePersistenceManager.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/AbstractBundlePersistenceManager.java?rev=1025995&r1=1025994&r2=1025995&view=diff
==============================================================================
--- jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/AbstractBundlePersistenceManager.java
(original)
+++ jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/AbstractBundlePersistenceManager.java
Thu Oct 21 13:42:18 2010
@@ -319,17 +319,6 @@ public abstract class AbstractBundlePers
             throws ItemStateException;
 
     /**
-     * Checks if a bundle exists in the underlying system.
-     *
-     * @param id the node id of the bundle
-     * @return <code>true</code> if the bundle exists;
-     *         <code>false</code> otherwise.
-     * @throws ItemStateException if an error while checking occurs.
-     */
-    protected abstract boolean existsBundle(NodeId id)
-            throws ItemStateException;
-
-    /**
      * Stores a bundle to the underlying system.
      *
      * @param bundle the bundle to store
@@ -632,7 +621,9 @@ public abstract class AbstractBundlePers
     }
 
     /**
-     * Gets the bundle for the given node id.
+     * Gets the bundle for the given node id. Read/write synchronization
+     * happens higher up at the SISM level, so we don't need to worry about
+     * conflicts here.
      *
      * @param id the id of the bundle to retrieve.
      * @return the bundle or <code>null</code> if the bundle does not exist
@@ -644,14 +635,12 @@ public abstract class AbstractBundlePers
         if (bundle == MISSING) {
             return null;
         } else if (bundle == null) {
-            synchronized (this) {
-                bundle = loadBundle(id);
-                if (bundle != null) {
-                    bundle.markOld();
-                    bundles.put(id, bundle, bundle.getSize());
-                } else {
-                    bundles.put(id, MISSING, 16);
-                }
+            bundle = loadBundle(id);
+            if (bundle != null) {
+                bundle.markOld();
+                bundles.put(id, bundle, bundle.getSize());
+            } else {
+                bundles.put(id, MISSING, 16);
             }
         }
         return bundle;
@@ -666,7 +655,6 @@ public abstract class AbstractBundlePers
     private void deleteBundle(NodePropBundle bundle) throws ItemStateException {
         destroyBundle(bundle);
         bundle.removeAllProperties();
-        bundles.remove(bundle.getId());
         bundles.put(bundle.getId(), MISSING, 16);
     }
 
@@ -684,7 +672,6 @@ public abstract class AbstractBundlePers
         // only put to cache if already exists. this is to ensure proper overwrite
         // and not creating big contention during bulk loads
         if (bundles.containsKey(bundle.getId())) {
-            bundles.remove(bundle.getId());
             bundles.put(bundle.getId(), bundle, bundle.getSize());
         }
     }

Modified: jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/BundleDbPersistenceManager.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/BundleDbPersistenceManager.java?rev=1025995&r1=1025994&r2=1025995&view=diff
==============================================================================
--- jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/BundleDbPersistenceManager.java
(original)
+++ jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/BundleDbPersistenceManager.java
Thu Oct 21 13:42:18 2010
@@ -779,7 +779,7 @@ public class BundleDbPersistenceManager 
         try {
             // skip root nodes (that point to itself)
             if (parentId != null && !id.toString().endsWith("babecafebabe")) {
-                if (!existsBundle(parentId)) {
+                if (loadBundle(parentId) == null) {
                     log.error("NodeState '" + id + "' references inexistent parent uuid '"
+ parentId + "'");
                 }
             }
@@ -1176,25 +1176,6 @@ public class BundleDbPersistenceManager 
     /**
      * {@inheritDoc}
      */
-    protected synchronized boolean existsBundle(NodeId id) throws ItemStateException {
-        ResultSet rs = null;
-        try {
-            Statement stmt = connectionManager.executeStmt(bundleSelectSQL, getKey(id));
-            rs = stmt.getResultSet();
-            // a bundle exists, if the result has at least one entry
-            return rs.next();
-        } catch (Exception e) {
-            String msg = "failed to check existence of bundle: " + id;
-            log.error(msg, e);
-            throw new ItemStateException(msg, e);
-        } finally {
-            closeResultSet(rs);
-        }
-    }
-
-    /**
-     * {@inheritDoc}
-     */
     protected synchronized void storeBundle(NodePropBundle bundle) throws ItemStateException
{
         try {
             ByteArrayOutputStream out = new ByteArrayOutputStream(INITIAL_BUFFER_SIZE);

Modified: jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/BundleFsPersistenceManager.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/BundleFsPersistenceManager.java?rev=1025995&r1=1025994&r2=1025995&view=diff
==============================================================================
--- jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/BundleFsPersistenceManager.java
(original)
+++ jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/bundle/BundleFsPersistenceManager.java
Thu Oct 21 13:42:18 2010
@@ -232,8 +232,7 @@ public class BundleFsPersistenceManager 
     /**
      * {@inheritDoc}
      */
-    protected synchronized NodePropBundle loadBundle(NodeId id)
-            throws ItemStateException {
+    protected NodePropBundle loadBundle(NodeId id) throws ItemStateException {
         DataInputStream din = null;
         try {
             String path = buildNodeFilePath(null, id).toString();
@@ -256,20 +255,6 @@ public class BundleFsPersistenceManager 
     }
 
     /**
-     * {@inheritDoc}
-     */
-    protected synchronized boolean existsBundle(NodeId id) throws ItemStateException {
-        try {
-            StringBuffer buf = buildNodeFilePath(null, id);
-            return itemFs.exists(buf.toString());
-        } catch (Exception e) {
-            String msg = "failed to check existence of bundle: " + id;
-            BundleFsPersistenceManager.log.error(msg, e);
-            throw new ItemStateException(msg, e);
-        }
-    }
-
-    /**
      * Creates the file path for the given node id that is
      * suitable for storing node states in a filesystem.
      *

Modified: jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/AbstractBundlePersistenceManager.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/AbstractBundlePersistenceManager.java?rev=1025995&r1=1025994&r2=1025995&view=diff
==============================================================================
--- jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/AbstractBundlePersistenceManager.java
(original)
+++ jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/AbstractBundlePersistenceManager.java
Thu Oct 21 13:42:18 2010
@@ -319,17 +319,6 @@ public abstract class AbstractBundlePers
             throws ItemStateException;
 
     /**
-     * Checks if a bundle exists in the underlying system.
-     *
-     * @param id the node id of the bundle
-     * @return <code>true</code> if the bundle exists;
-     *         <code>false</code> otherwise.
-     * @throws ItemStateException if an error while checking occurs.
-     */
-    protected abstract boolean existsBundle(NodeId id)
-            throws ItemStateException;
-
-    /**
      * Stores a bundle to the underlying system.
      *
      * @param bundle the bundle to store
@@ -630,7 +619,9 @@ public abstract class AbstractBundlePers
     }
 
     /**
-     * Gets the bundle for the given node id.
+     * Gets the bundle for the given node id. Read/write synchronization
+     * happens higher up at the SISM level, so we don't need to worry about
+     * conflicts here.
      *
      * @param id the id of the bundle to retrieve.
      * @return the bundle or <code>null</code> if the bundle does not exist
@@ -642,14 +633,12 @@ public abstract class AbstractBundlePers
         if (bundle == MISSING) {
             return null;
         } else if (bundle == null) {
-            synchronized (this) {
-                bundle = loadBundle(id);
-                if (bundle != null) {
-                    bundle.markOld();
-                    bundles.put(id, bundle, bundle.getSize());
-                } else {
-                    bundles.put(id, MISSING, 16);
-                }
+            bundle = loadBundle(id);
+            if (bundle != null) {
+                bundle.markOld();
+                bundles.put(id, bundle, bundle.getSize());
+            } else {
+                bundles.put(id, MISSING, 16);
             }
         }
         return bundle;
@@ -664,7 +653,6 @@ public abstract class AbstractBundlePers
     private void deleteBundle(NodePropBundle bundle) throws ItemStateException {
         destroyBundle(bundle);
         bundle.removeAllProperties();
-        bundles.remove(bundle.getId());
         bundles.put(bundle.getId(), MISSING, 16);
     }
 
@@ -682,7 +670,6 @@ public abstract class AbstractBundlePers
         // only put to cache if already exists. this is to ensure proper
         // overwrite and not creating big contention during bulk loads
         if (bundles.containsKey(bundle.getId())) {
-            bundles.remove(bundle.getId());
             bundles.put(bundle.getId(), bundle, bundle.getSize());
         }
     }

Modified: jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/BundleDbPersistenceManager.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/BundleDbPersistenceManager.java?rev=1025995&r1=1025994&r2=1025995&view=diff
==============================================================================
--- jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/BundleDbPersistenceManager.java
(original)
+++ jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/BundleDbPersistenceManager.java
Thu Oct 21 13:42:18 2010
@@ -744,7 +744,7 @@ public class BundleDbPersistenceManager 
         try {
             // skip root nodes (that point to itself)
             if (parentId != null && !id.toString().endsWith("babecafebabe")) {
-                if (!existsBundle(parentId)) {
+                if (loadBundle(parentId) == null) {
                     log.error("NodeState '" + id + "' references inexistent parent uuid '"
+ parentId + "'");
                 }
             }
@@ -1024,8 +1024,7 @@ public class BundleDbPersistenceManager 
     /**
      * {@inheritDoc}
      */
-    protected synchronized NodePropBundle loadBundle(NodeId id)
-            throws ItemStateException {
+    protected NodePropBundle loadBundle(NodeId id) throws ItemStateException {
         return loadBundle(id, false);
     }
 
@@ -1064,7 +1063,7 @@ public class BundleDbPersistenceManager 
      *         exist.
      * @throws ItemStateException if an error while loading occurs.
      */
-    protected synchronized NodePropBundle loadBundle(NodeId id, boolean checkBeforeLoading)
+    protected NodePropBundle loadBundle(NodeId id, boolean checkBeforeLoading)
             throws ItemStateException {
         ResultSet rs = null;
         
@@ -1102,24 +1101,6 @@ public class BundleDbPersistenceManager 
     /**
      * {@inheritDoc}
      */
-    protected synchronized boolean existsBundle(NodeId id) throws ItemStateException {
-        ResultSet rs = null;
-        try {
-            rs = conHelper.exec(bundleSelectSQL, getKey(id), false, 0);
-            // a bundle exists, if the result has at least one entry
-            return rs.next();
-        } catch (Exception e) {
-            String msg = "failed to check existence of bundle: " + id;
-            log.error(msg, e);
-            throw new ItemStateException(msg, e);
-        } finally {
-            DbUtility.close(rs);
-        }
-    }
-
-    /**
-     * {@inheritDoc}
-     */
     protected synchronized void storeBundle(NodePropBundle bundle) throws ItemStateException
{
         try {
             ByteArrayOutputStream out = new ByteArrayOutputStream(INITIAL_BUFFER_SIZE);

Modified: jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/BundleFsPersistenceManager.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/BundleFsPersistenceManager.java?rev=1025995&r1=1025994&r2=1025995&view=diff
==============================================================================
--- jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/BundleFsPersistenceManager.java
(original)
+++ jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/BundleFsPersistenceManager.java
Thu Oct 21 13:42:18 2010
@@ -231,8 +231,7 @@ public class BundleFsPersistenceManager 
     /**
      * {@inheritDoc}
      */
-    protected synchronized NodePropBundle loadBundle(NodeId id)
-            throws ItemStateException {
+    protected NodePropBundle loadBundle(NodeId id) throws ItemStateException {
         DataInputStream din = null;
         try {
             String path = buildNodeFilePath(null, id).toString();
@@ -255,20 +254,6 @@ public class BundleFsPersistenceManager 
     }
 
     /**
-     * {@inheritDoc}
-     */
-    protected synchronized boolean existsBundle(NodeId id) throws ItemStateException {
-        try {
-            StringBuffer buf = buildNodeFilePath(null, id);
-            return itemFs.exists(buf.toString());
-        } catch (Exception e) {
-            String msg = "failed to check existence of bundle: " + id;
-            BundleFsPersistenceManager.log.error(msg, e);
-            throw new ItemStateException(msg, e);
-        }
-    }
-
-    /**
      * Creates the file path for the given node id that is
      * suitable for storing node states in a filesystem.
      *

Modified: jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/PostgreSQLPersistenceManager.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/PostgreSQLPersistenceManager.java?rev=1025995&r1=1025994&r2=1025995&view=diff
==============================================================================
--- jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/PostgreSQLPersistenceManager.java
(original)
+++ jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/pool/PostgreSQLPersistenceManager.java
Thu Oct 21 13:42:18 2010
@@ -92,10 +92,9 @@ public class PostgreSQLPersistenceManage
      * 
      * {@inheritDoc}
      */
-    protected synchronized NodePropBundle loadBundle(NodeId id)
-            throws ItemStateException {
+    protected NodePropBundle loadBundle(NodeId id) throws ItemStateException {
         ResultSet rs = null;
-        try {        	
+        try {
             rs = conHelper.exec(bundleSelectSQL, getKey(id), false, 0);
             if (rs.next()) {
                 InputStream input = rs.getBinaryStream(1);

Modified: jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/ItemStateReferenceCache.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/ItemStateReferenceCache.java?rev=1025995&r1=1025994&r2=1025995&view=diff
==============================================================================
--- jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/ItemStateReferenceCache.java
(original)
+++ jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/ItemStateReferenceCache.java
Thu Oct 21 13:42:18 2010
@@ -18,11 +18,11 @@ package org.apache.jackrabbit.core.state
 
 import org.apache.commons.collections.map.ReferenceMap;
 import org.apache.jackrabbit.core.id.ItemId;
-import org.apache.jackrabbit.core.util.Dumpable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.io.PrintStream;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 
 /**
@@ -43,36 +43,27 @@ import java.util.Map;
  * </ul>
  * This implementation of ItemStateCache is thread-safe.
  */
-public class ItemStateReferenceCache implements ItemStateCache, Dumpable {
+public class ItemStateReferenceCache implements ItemStateCache {
 
     /** Logger instance */
     private static Logger log = LoggerFactory.getLogger(ItemStateReferenceCache.class);
 
     /**
-     * primary cache storing weak references to <code>ItemState</code>
-     * instances.
+     * Cache that automatically flushes entries based on some eviction policy;
+     * entries flushed from the secondary cache will be indirectly flushed
+     * from the reference map by the garbage collector if they thus are
+     * rendered weakly reachable.
      */
-    @SuppressWarnings("unchecked")
-    private final Map<ItemId, ItemState> refs =
-        // I tried using soft instead of weak references here, but that
-        // seems to have some unexpected performance consequences (notable
-        // increase in the JCR TCK run time). So even though soft references
-        // are generally recommended over weak references for caching
-        // purposes, it seems that using weak references is safer here.
-        new ReferenceMap(ReferenceMap.HARD, ReferenceMap.WEAK);
+    private final ItemStateCache cache;
 
     /**
-     * secondary cache that automatically flushes entries based on some
-     * eviction policy; entries flushed from the secondary cache will be
-     * indirectly flushed from the primary (reference) cache by the garbage
-     * collector if they thus are rendered weakly reachable.
+     * Segments of the weak reference map used to keep track of item states.
      */
-    private final ItemStateCache cache;
+    private final Map<ItemId, ItemState>[] segments;
 
     /**
      * Creates a new <code>ItemStateReferenceCache</code> that uses a
-     * <code>MLRUItemStateCache</code> instance as internal secondary
-     * cache.
+     * <code>MLRUItemStateCache</code> instance as internal cache.
      */
     public ItemStateReferenceCache(ItemStateCacheFactory cacheFactory) {
         this(cacheFactory.newItemStateCache());
@@ -85,95 +76,143 @@ public class ItemStateReferenceCache imp
      *
      * @param cache secondary cache implementing a custom eviction policy
      */
+    @SuppressWarnings("unchecked")
     public ItemStateReferenceCache(ItemStateCache cache) {
         this.cache = cache;
+        this.segments = new Map[Runtime.getRuntime().availableProcessors()];
+        for (int i = 0; i < segments.length; i++) {
+            // I tried using soft instead of weak references here, but that
+            // seems to have some unexpected performance consequences (notable
+            // increase in the JCR TCK run time). So even though soft references
+            // are generally recommended over weak references for caching
+            // purposes, it seems that using weak references is safer here.
+            segments[i] =
+                new ReferenceMap(ReferenceMap.HARD, ReferenceMap.WEAK);
+        }
+    }
+
+    /**
+     * Returns the reference map segment for the given entry key. The segment
+     * is selected based on the hash code of the key, after a transformation
+     * to prevent interfering with the optimal performance of the segment
+     * hash map.
+     *
+     * @param id item identifer
+     * @return reference map segment
+     */
+    private Map<ItemId, ItemState> getSegment(ItemId id) {
+        // Unsigned shift right to prevent negative indexes and to
+        // prevent too similar keys to all get stored in the same segment
+        return segments[(id.hashCode() >>> 1) % segments.length];
     }
 
     //-------------------------------------------------------< ItemStateCache >
     /**
      * {@inheritDoc}
      */
-    public synchronized boolean isCached(ItemId id) {
-        // check primary cache
-        return refs.containsKey(id);
+    public boolean isCached(ItemId id) {
+        Map<ItemId, ItemState> segment = getSegment(id);
+        synchronized (segment) {
+            return segment.containsKey(id);
+        }
     }
 
     /**
      * {@inheritDoc}
      */
-    public synchronized ItemState retrieve(ItemId id) {
-        // fake call to update stats of secondary cache
-        cache.retrieve(id);
+    public ItemState retrieve(ItemId id) {
+        // Update the access statistics in the cache
+        ItemState state = cache.retrieve(id);
+        if (state != null) {
+            // Return fast to avoid the second lookup below
+            return state;
+        }
 
-        // retrieve from primary cache
-        return refs.get(id);
+        Map<ItemId, ItemState> segment = getSegment(id);
+        synchronized (segment) {
+            return segment.get(id);
+        }
     }
 
     /**
      * {@inheritDoc}
      */
-    public synchronized ItemState[] retrieveAll() {
-        // values of primary cache
-        return (ItemState[]) refs.values().toArray(new ItemState[refs.size()]);
+    public ItemState[] retrieveAll() {
+        List<ItemState> states = new ArrayList<ItemState>();
+        for (int i = 0; i < segments.length; i++) {
+            synchronized (segments[i]) {
+                states.addAll(segments[i].values());
+            }
+        }
+        return states.toArray(new ItemState[states.size()]);
     }
 
     /**
      * {@inheritDoc}
      */
-    public synchronized void cache(ItemState state) {
-        ItemId id = state.getId();
-        if (refs.containsKey(id)) {
-            log.warn("overwriting cached entry " + id);
-        }
-        // fake call to update stats of secondary cache
+    public void cache(ItemState state) {
+        // Update the cache
         cache.cache(state);
-        // store weak reference in primary cache
-        refs.put(id, state);
 
+        // Store a weak reference in the reference map
+        ItemId id = state.getId();
+        Map<ItemId, ItemState> segment = getSegment(id);
+        synchronized (segment) {
+            if (segment.containsKey(id)) {
+                log.warn("overwriting cached entry " + id);
+            }
+            segment.put(id, state);
+        }
     }
 
     /**
      * {@inheritDoc}
      */
-    public synchronized void evict(ItemId id) {
-        // fake call to update stats of secondary cache
+    public void evict(ItemId id) {
+        // Update the cache
         cache.evict(id);
-        // remove from primary cache
-        refs.remove(id);
+        // Remove from reference map
+        // TODO: Allow the weak reference to be cleared automatically?
+        Map<ItemId, ItemState> segment = getSegment(id);
+        synchronized (segment) {
+            segment.remove(id);
+        }
     }
 
     /**
      * {@inheritDoc}
      */
-    public synchronized void dispose() {
+    public void dispose() {
         cache.dispose();
     }
 
     /**
      * {@inheritDoc}
      */
-    public synchronized void evictAll() {
-        // fake call to update stats of secondary cache
+    public void evictAll() {
+        // Update the cache
         cache.evictAll();
-        // remove all weak references from primary cache
-        refs.clear();
+        // remove all weak references from reference map
+        // TODO: Allow the weak reference to be cleared automatically?
+        for (int i = 0; i < segments.length; i++) {
+            synchronized (segments[i]) {
+                segments[i].clear();
+            }
+        }
     }
 
     /**
      * {@inheritDoc}
      */
-    public synchronized boolean isEmpty() {
-        // check primary cache
-        return refs.isEmpty();
+    public boolean isEmpty() {
+        for (int i = 0; i < segments.length; i++) {
+            synchronized (segments[i]) {
+                if (!segments[i].isEmpty()) {
+                    return false;
+                }
+            }
+        }
+        return true;
     }
 
-    //-------------------------------------------------------------< Dumpable >
-    /**
-     * {@inheritDoc}
-     */
-    public synchronized void dump(PrintStream ps) {
-        ps.println("ItemStateReferenceCache (" + this + ")");
-        ps.println("  refs: " + refs.keySet());
-        ps.println();
-    }
 }

Modified: jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/LocalItemStateManager.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/LocalItemStateManager.java?rev=1025995&r1=1025994&r2=1025995&view=diff
==============================================================================
--- jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/LocalItemStateManager.java
(original)
+++ jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/LocalItemStateManager.java
Thu Oct 21 13:42:18 2010
@@ -163,19 +163,17 @@ public class LocalItemStateManager
             return state;
         }
 
-        // check cache. synchronized to ensure an entry is not created twice.
-        synchronized (this) {
-            state = cache.retrieve(id);
-            if (state == null) {
-                // regular behaviour
-                if (id.denotesNode()) {
-                    state = getNodeState((NodeId) id);
-                } else {
-                    state = getPropertyState((PropertyId) id);
-                }
+        // check cache
+        state = cache.retrieve(id);
+        if (state == null) {
+            // regular behaviour
+            if (id.denotesNode()) {
+                state = getNodeState((NodeId) id);
+            } else {
+                state = getPropertyState((PropertyId) id);
             }
-            return state;
         }
+        return state;
     }
 
     /**

Modified: jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/SharedItemStateManager.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/SharedItemStateManager.java?rev=1025995&r1=1025994&r2=1025995&view=diff
==============================================================================
--- jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/SharedItemStateManager.java
(original)
+++ jackrabbit/branches/2.1/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/SharedItemStateManager.java
Thu Oct 21 13:42:18 2010
@@ -1708,21 +1708,8 @@ public class SharedItemStateManager
             // not found in cache, load from persistent storage
             state = loadItemState(id);
             state.setStatus(ItemState.STATUS_EXISTING);
-            synchronized (this) {
-                // Use a double check to ensure that the cache entry is
-                // not created twice. We don't synchronize the entire
-                // method to allow the first cache retrieval to proceed
-                // even when another thread is loading a new item state.
-                ItemState cachedState = cache.retrieve(id);
-                if (cachedState == null) {
-                    // put it in cache
-                    cache.cache(state);
-                    // set parent container
-                    state.setContainer(this);
-                } else {
-                    state = cachedState;
-                }
-            }
+            state.setContainer(this);
+            cache.cache(state);
         }
         return state;
     }



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