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Posted to commits@jackrabbit.apache.org by ju...@apache.org on 2010/10/21 16:48:26 UTC
svn commit: r1026017 - in /jackrabbit/branches/2.0: ./
jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/util/
jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/
Author: jukka
Date: Thu Oct 21 14:48:25 2010
New Revision: 1026017
URL: http://svn.apache.org/viewvc?rev=1026017&view=rev
Log:
2.0: Merged revisions 1025933 and 1025957 (JCR-2699)
Modified:
jackrabbit/branches/2.0/ (props changed)
jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/util/BundleCache.java
jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/util/LRUNodeIdCache.java
jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/ItemState.java
jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/MLRUItemStateCache.java
jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/NodeState.java
jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/PropertyState.java
jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/SharedItemStateManager.java
Propchange: jackrabbit/branches/2.0/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Thu Oct 21 14:48:25 2010
@@ -1,6 +1,6 @@
/jackrabbit/branches/1.5:794012,794100,794102
-/jackrabbit/branches/2.1:955309,955314,982266,982277,982505,998310
+/jackrabbit/branches/2.1:955309,955314,982266,982277,982505,998310,1025933,1025957
/jackrabbit/sandbox/JCR-1456:774917-886178
/jackrabbit/sandbox/JCR-2170:812417-816332
/jackrabbit/sandbox/tripod-JCR-2209:795441-795863
-/jackrabbit/trunk:891595,891629,892253,892263,894150-894151,896408,896513,896532,896857,896870,896876,896908,896940,896942-896943,896969,896977,897071,897836,897842,897858,897935,897983,897992-897993,897996,898002,898042,898267,898325,898540,898677,898699,898701,898715,898872,899102,899181,899391,899393-899394,899583,899594,899643,900305,900310,900314,900453,900702,900736,900762-900763,900767,900782,901095,901122,901139,901144,901170,901176,901191,901193,901196,901216,901228,901285,902058,902062,926324,928888,936668,955222,955229,955307,955852,965539,996810
+/jackrabbit/trunk:891595,891629,892253,892263,894150-894151,896408,896513,896532,896857,896870,896876,896908,896940,896942-896943,896969,896977,897071,897836,897842,897858,897935,897983,897992-897993,897996,898002,898042,898267,898325,898540,898677,898699,898701,898715,898872,899102,899181,899391,899393-899394,899583,899594,899643,900305,900310,900314,900453,900702,900736,900762-900763,900767,900782,901095,901122,901139,901144,901170,901176,901191,901193,901196,901216,901228,901285,902058,902062,926324,928888,936668,955222,955229,955307,955852,965539,996810,1001707,1002065-1002066,1002084,1002101-1002102
Modified: jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/util/BundleCache.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/util/BundleCache.java?rev=1026017&r1=1026016&r2=1026017&view=diff
==============================================================================
--- jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/util/BundleCache.java (original)
+++ jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/util/BundleCache.java Thu Oct 21 14:48:25 2010
@@ -16,7 +16,9 @@
*/
package org.apache.jackrabbit.core.persistence.util;
-import org.apache.commons.collections.map.LinkedMap;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
import org.apache.jackrabbit.core.id.NodeId;
import org.slf4j.LoggerFactory;
import org.slf4j.Logger;
@@ -54,15 +56,29 @@ public class BundleCache {
/**
* a map of the cache entries
*/
- private LinkedMap bundles = new LinkedMap();
+ private final LinkedHashMap<NodeId, NodePropBundle> bundles;
/**
* Creates a new BundleCache
*
* @param maxSize the maximum size of this cache in bytes.
*/
+ @SuppressWarnings("serial")
public BundleCache(long maxSize) {
this.maxSize = maxSize;
+ this.bundles = new LinkedHashMap<NodeId, NodePropBundle>(
+ (int) maxSize / 1024, 0.75f, true /* access-ordered */) {
+ @Override
+ protected boolean removeEldestEntry(
+ Map.Entry<NodeId, NodePropBundle> e) {
+ if (curSize > BundleCache.this.maxSize) {
+ curSize -= e.getValue().getSize();
+ return true;
+ } else {
+ return false;
+ }
+ }
+ };
}
/**
@@ -90,11 +106,9 @@ public class BundleCache {
* @param id the id of the bundle
* @return the cached bundle or <code>null</code>
*/
- public NodePropBundle get(NodeId id) {
- Entry entry = (Entry) bundles.remove(id);
- if (entry != null) {
- // at end
- bundles.put(id, entry);
+ public synchronized NodePropBundle get(NodeId id) {
+ NodePropBundle bundle = bundles.get(id);
+ if (bundle != null) {
hits++;
} else {
misses++;
@@ -106,32 +120,21 @@ public class BundleCache {
log.info("num=" + bundles.size() + " mem=" + c + "k max=" + m + "k avg=" + a
+ " hits=" + hits + " miss=" + misses);
}
- return entry == null ? null : entry.bundle;
+ return bundle;
}
/**
- * Puts a bunlde to the cache. If the new size of the cache exceeds the
- * {@link #getMaxSize() max size} of the cache it will remove bundles from
- * this cache until the limit is satisfied.
+ * Puts a bundle to the cache.
*
* @param bundle the bunlde to put to the cache
*/
- public void put(NodePropBundle bundle) {
- Entry entry = (Entry) bundles.remove(bundle.getId());
- if (entry == null) {
- entry = new Entry(bundle, bundle.getSize());
- } else {
- curSize -= entry.size;
- entry.bundle = bundle;
- entry.size = bundle.getSize();
- }
- bundles.put(bundle.getId(), entry);
- curSize += entry.size;
- // now limit size of cache
- while (curSize > maxSize) {
- entry = (Entry) bundles.remove(0);
- curSize -= entry.size;
+ public synchronized void put(NodePropBundle bundle) {
+ NodePropBundle previous = bundles.get(bundle.getId());
+ if (previous != null) {
+ curSize -= previous.getSize();
}
+ bundles.put(bundle.getId(), bundle);
+ curSize += bundle.getSize();
}
/**
@@ -141,7 +144,7 @@ public class BundleCache {
* @return <code>true</code> if the bundle is cached;
* <code>false</code> otherwise.
*/
- public boolean contains(NodeId id) {
+ public synchronized boolean contains(NodeId id) {
return bundles.containsKey(id);
}
@@ -152,51 +155,22 @@ public class BundleCache {
* @return the previously cached bunlde or <code>null</code> of the bundle
* was not cached.
*/
- public NodePropBundle remove(NodeId id) {
- Entry entry = (Entry) bundles.remove(id);
- if (entry != null) {
- curSize -= entry.size;
- return entry.bundle;
- } else {
- return null;
+ public synchronized NodePropBundle remove(NodeId id) {
+ NodePropBundle bundle = bundles.remove(id);
+ if (bundle != null) {
+ curSize -= bundle.getSize();
}
+ return bundle;
}
/**
* Clears this cache and removes all bundles.
*/
- public void clear() {
+ public synchronized void clear() {
bundles.clear();
curSize = 0;
hits = 0;
misses = 0;
}
- /**
- * Internal class that holds the bundles.
- */
- private static final class Entry {
-
- /**
- * the cached bundle
- */
- private NodePropBundle bundle;
-
- /**
- * the memory usage of the bundle in bytes
- */
- private long size;
-
- /**
- * Creates a new entry.
- *
- * @param bundle the bundle to cache
- * @param size the size of the bundle
- */
- public Entry(NodePropBundle bundle, long size) {
- this.bundle = bundle;
- this.size = size;
- }
- }
-
}
Modified: jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/util/LRUNodeIdCache.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/util/LRUNodeIdCache.java?rev=1026017&r1=1026016&r2=1026017&view=diff
==============================================================================
--- jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/util/LRUNodeIdCache.java (original)
+++ jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/persistence/util/LRUNodeIdCache.java Thu Oct 21 14:48:25 2010
@@ -16,7 +16,9 @@
*/
package org.apache.jackrabbit.core.persistence.util;
-import org.apache.commons.collections.map.LinkedMap;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
import org.apache.jackrabbit.core.id.NodeId;
import org.slf4j.LoggerFactory;
import org.slf4j.Logger;
@@ -34,7 +36,7 @@ public class LRUNodeIdCache {
/**
* The maximum number of ids to cache
*/
- private long maxSize = 10240;
+ private static final int maxSize = 10240;
/**
* the number of cache hits
@@ -49,7 +51,14 @@ public class LRUNodeIdCache {
/**
* the map of cached ids
*/
- private final LinkedMap missing = new LinkedMap();
+ @SuppressWarnings("serial")
+ private final LinkedHashMap<NodeId, NodeId> missing =
+ new LinkedHashMap<NodeId, NodeId>(maxSize * 2, 0.75f, true) {
+ @Override
+ protected boolean removeEldestEntry(Map.Entry<NodeId, NodeId> e) {
+ return size() > maxSize;
+ }
+ };
/**
* Checks if the given id is contained in this cached.
@@ -58,31 +67,25 @@ public class LRUNodeIdCache {
* @return <code>true</code> if the id is cached;
* <code>false</code> otherwise.
*/
- public boolean contains(NodeId id) {
- Object o = missing.remove(id);
- if (o == null) {
- misses++;
- } else {
- missing.put(id, id);
+ public synchronized boolean contains(NodeId id) {
+ boolean rv = missing.get(id) != null;
+ if (rv) {
hits++;
+ } else {
+ misses++;
}
if (log.isInfoEnabled() && (hits + misses) % 10000 == 0) {
log.info("num=" + missing.size() + "/" + maxSize + " hits=" + hits + " miss=" + misses);
}
- return o != null;
+ return rv;
}
/**
* Puts the given id to this cache.
* @param id the id to put.
*/
- public void put(NodeId id) {
- if (!missing.containsKey(id)) {
- if (missing.size() == maxSize) {
- missing.remove(0);
- }
- missing.put(id, id);
- }
+ public synchronized void put(NodeId id) {
+ missing.put(id, id);
}
/**
@@ -91,14 +94,14 @@ public class LRUNodeIdCache {
* @return <code>true</code> if the id was cached;
* <code>false</code> otherwise.
*/
- public boolean remove(NodeId id) {
+ public synchronized boolean remove(NodeId id) {
return missing.remove(id) != null;
}
/**
* Clears this cache.
*/
- public void clear() {
+ public synchronized void clear() {
missing.clear();
}
Modified: jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/ItemState.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/ItemState.java?rev=1026017&r1=1026016&r2=1026017&view=diff
==============================================================================
--- jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/ItemState.java (original)
+++ jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/ItemState.java Thu Oct 21 14:48:25 2010
@@ -421,4 +421,5 @@ public abstract class ItemState {
* @return the approximate memory consumption of this state.
*/
public abstract long calculateMemoryFootprint();
+
}
Modified: jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/MLRUItemStateCache.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/MLRUItemStateCache.java?rev=1026017&r1=1026016&r2=1026017&view=diff
==============================================================================
--- jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/MLRUItemStateCache.java (original)
+++ jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/MLRUItemStateCache.java Thu Oct 21 14:48:25 2010
@@ -16,7 +16,10 @@
*/
package org.apache.jackrabbit.core.state;
-import java.util.Iterator;
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
import org.apache.commons.collections.map.LinkedMap;
import org.apache.jackrabbit.core.id.ItemId;
@@ -41,16 +44,16 @@ public class MLRUItemStateCache implemen
public static final int DEFAULT_MAX_MEM = 4 * 1024 * 1024;
/** the amount of memory the entries use */
- private long totalMem;
+ private volatile long totalMem;
/** the maximum of memory the cache may use */
- private long maxMem;
+ private volatile long maxMem;
/** the number of writes */
- private long numWrites;
+ private volatile long numWrites;
/** the access count */
- private long accessCount;
+ private volatile long accessCount;
/** the cache access listeners */
private CacheAccessListener accessListener;
@@ -58,7 +61,7 @@ public class MLRUItemStateCache implemen
/**
* A cache for <code>ItemState</code> instances
*/
- private final LinkedMap cache = new LinkedMap();
+ private final Map<ItemId, Entry> cache;
/**
* Constructs a new, empty <code>ItemStateCache</code> with a maximum amount
@@ -74,8 +77,21 @@ public class MLRUItemStateCache implemen
*
* @param maxMem the maximum amount of memory this cache may use.
*/
+ @SuppressWarnings("serial")
private MLRUItemStateCache(int maxMem) {
this.maxMem = maxMem;
+ this.cache = new LinkedHashMap<ItemId, MLRUItemStateCache.Entry>(
+ maxMem / 1024, 0.75f, true /* access-ordered */) {
+ @Override
+ protected boolean removeEldestEntry(Map.Entry<ItemId, Entry> e) {
+ if (totalMem > MLRUItemStateCache.this.maxMem) {
+ totalMem -= e.getValue().size;
+ return true;
+ } else {
+ return false;
+ }
+ }
+ };
}
//-------------------------------------------------------< ItemStateCache >
@@ -94,10 +110,8 @@ public class MLRUItemStateCache implemen
public ItemState retrieve(ItemId id) {
touch();
synchronized (cache) {
- Entry entry = (Entry) cache.remove(id);
+ Entry entry = cache.get(id);
if (entry != null) {
- // 'touch' item, by adding at end of list
- cache.put(id, entry);
return entry.state;
} else {
return null;
@@ -110,7 +124,12 @@ public class MLRUItemStateCache implemen
*/
public ItemState[] retrieveAll() {
synchronized (cache) {
- return (ItemState[]) cache.values().toArray(new ItemState[cache.size()]);
+ ItemState[] states = new ItemState[cache.size()];
+ int i = 0;
+ for (Entry entry : cache.values()) {
+ states[i++] = entry.state;
+ }
+ return states;
}
}
@@ -120,7 +139,7 @@ public class MLRUItemStateCache implemen
public void update(ItemId id) {
touch();
synchronized (cache) {
- Entry entry = (Entry) cache.get(id);
+ Entry entry = cache.get(id);
if (entry != null) {
totalMem -= entry.size;
entry.recalc();
@@ -141,33 +160,21 @@ public class MLRUItemStateCache implemen
evict(id);
}
Entry entry = new Entry(state);
- cache.put(id, entry);
totalMem += entry.size;
- shrinkIfRequired();
+ cache.put(id, entry);
if (numWrites++ % 10000 == 0 && log.isDebugEnabled()) {
log.debug(this + " size=" + cache.size() + ", " + totalMem + "/" + maxMem);
}
}
}
- private void shrinkIfRequired() {
- // remove items, if too many
- synchronized (cache) {
- while (totalMem > maxMem) {
- ItemId id = (ItemId) cache.firstKey();
- Entry entry = (Entry) cache.remove(id);
- totalMem -= entry.size;
- }
- }
- }
-
/**
* {@inheritDoc}
*/
public void evict(ItemId id) {
touch();
synchronized (cache) {
- Entry entry = (Entry) cache.remove(id);
+ Entry entry = cache.remove(id);
if (entry != null) {
totalMem -= entry.size;
}
@@ -220,15 +227,6 @@ public class MLRUItemStateCache implemen
* {@inheritDoc}
*/
public long getMemoryUsed() {
- synchronized (cache) {
- totalMem = 0;
- Iterator iter = cache.values().iterator();
- while (iter.hasNext()) {
- Entry entry = (Entry) iter.next();
- entry.recalc();
- totalMem += entry.size;
- }
- }
return totalMem;
}
@@ -247,7 +245,21 @@ public class MLRUItemStateCache implemen
public void setMaxMemorySize(long size) {
synchronized (cache) {
this.maxMem = size;
- shrinkIfRequired();
+
+ // remove items, if too many
+ if (totalMem > maxMem) {
+ totalMem = 0;
+ List<Map.Entry<ItemId, Entry>> entries =
+ new ArrayList<Map.Entry<ItemId, Entry>>(cache.entrySet());
+ for (Map.Entry<ItemId, Entry> entry : entries) {
+ long entrySize = entry.getValue().size;
+ if (totalMem + entrySize > maxMem) {
+ cache.remove(entry.getKey());
+ } else {
+ totalMem += entrySize;
+ }
+ }
+ }
}
}
Modified: jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/NodeState.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/NodeState.java?rev=1026017&r1=1026016&r2=1026017&view=diff
==============================================================================
--- jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/NodeState.java (original)
+++ jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/NodeState.java Thu Oct 21 14:48:25 2010
@@ -802,27 +802,26 @@ public class NodeState extends ItemState
/**
* {@inheritDoc}
*/
+ @Override
public long calculateMemoryFootprint() {
/*
private Name nodeTypeName;
private Set mixinTypeNames = Collections.EMPTY_SET;
private NodeId id;
private NodeId parentId;
- private NodeDefId defId;
private ChildNodeEntries childNodeEntries = new ChildNodeEntries();
- private boolean sharedChildNodeEntries = false;
private HashSet propertyNames = new HashSet();
- private boolean sharedPropertyNames = false;
+ private boolean sharedSet = Set<NodeId>;
+ private boolean sharedSetRW = false;
+ private NodeStateListener listener = ...;
- we assume an average Name localname of 30 chars.
- NodeId = 8 + UUID(24) + hashcode(4) = 36
- Name = 8 + hash(4) + string(38+2*len) + namespace(4) + localName(38+2*len) ~ 250
- NodeDefId = 8 + id(4) = 12
- ChildNodeEntries = 8 + n * (name(256) + index(4) + id(36) + hashentry(16)) ~ n*300
- PropNames = 8 + n * ( name(250))
+ We assume only 16 bytes per name or node id,
+ as they are shared between states
+ ChildNodeEntries = 8 + n * (name(16) + index(4) + id(16) + hashentry(16)) ~ n*52
+ MixinTypeNames/PropNames = 8 + n * (name(16) + hashentry(16))
*/
- return 350 + mixinTypeNames.size() * 250 + childNodeEntries.size() * 300
- + propertyNames.size() * 250;
+ return 100 + mixinTypeNames.size() * 32 + childNodeEntries.size() * 52
+ + propertyNames.size() * 32;
}
/**
Modified: jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/PropertyState.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/PropertyState.java?rev=1026017&r1=1026016&r2=1026017&view=diff
==============================================================================
--- jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/PropertyState.java (original)
+++ jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/PropertyState.java Thu Oct 21 14:48:25 2010
@@ -196,20 +196,21 @@ public class PropertyState extends ItemS
/**
* {@inheritDoc}
*/
+ @Override
public long calculateMemoryFootprint() {
/*
private PropertyId id;
private InternalValue[] values;
private int type;
private boolean multiValued;
- private PropDefId defId;
- we assume an average Name localname of 30 chars.
- PropertyId = 8 + nodeId(36) * name(250) + hash(4) ~ 300;
- NodeDefId = 8 + id(4) = 12
+ We assume only 16 bytes per name or node id,
+ as they are shared between states
+ PropertyId = 8 + nodeId(16) + name(16) + hash(4) ~ 44;
InternalValue = 8 + n * (values) ~ 8 + n*100;
value=approx 100 bytes.
*/
- return 350 + values.length * 100;
+ return 64 + values.length * 100;
}
+
}
Modified: jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/SharedItemStateManager.java
URL: http://svn.apache.org/viewvc/jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/SharedItemStateManager.java?rev=1026017&r1=1026016&r2=1026017&view=diff
==============================================================================
--- jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/SharedItemStateManager.java (original)
+++ jackrabbit/branches/2.0/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/state/SharedItemStateManager.java Thu Oct 21 14:48:25 2010
@@ -257,9 +257,12 @@ public class SharedItemStateManager
ISMLocking.ReadLock readLock = acquireReadLock(id);
try {
// check internal first
- if (hasNonVirtualItemState(id)) {
- return getNonVirtualItemState(id);
- }
+ return getNonVirtualItemState(id);
+ } catch (NoSuchItemStateException e) {
+ // Fall through to virtual state providers. We can afford the
+ // exception-for-control-flow performance hit here, as almost
+ // all performance-critical content is non-virtual. With this
+ // catch we can avoid an extra hasNonVirtualItemState() call.
} finally {
readLock.release();
}
@@ -1700,21 +1703,28 @@ public class SharedItemStateManager
*/
private ItemState getNonVirtualItemState(ItemId id)
throws NoSuchItemStateException, ItemStateException {
-
- // check cache; synchronized to ensure an entry is not created twice.
- synchronized (cache) {
- ItemState state = cache.retrieve(id);
- if (state == null) {
- // not found in cache, load from persistent storage
- state = loadItemState(id);
- state.setStatus(ItemState.STATUS_EXISTING);
- // put it in cache
- cache.cache(state);
- // set parent container
- state.setContainer(this);
+ ItemState state = cache.retrieve(id);
+ if (state == null) {
+ // 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;
+ }
}
- return state;
}
+ return state;
}
/**