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Posted to dev@cocoon.apache.org by vo...@basf-it-services.com on 2003/04/27 18:57:43 UTC
Re: cvs commit: cocoon-2.1/src/deprecated/java/org/apache/cocoon/components/store
MRUMemoryStore.java
Hi Vadim,
I think this will be a great improvement.
In cocoon.xconf the excalibur store is used which has a bad performance all
methods are synchronized an inside the synchronized block a store to the
persistent store can happen if the memory store is full. Arrrrggggggg very
very bad performance!!!
<role name="org.apache.excalibur.store.Store/TransientStore"
shorthand="transient-store"
default-class="org.apache.excalibur.store.impl.MRUMemoryStore"/>
I think is make sense to use your implementation or move your code to
excalibur before excalibur-store get released.
Thanks,
Volker
vgritsenko 2003/04/27 09:41:31
Modified: src/deprecated/java/org/apache/cocoon/components/store
MRUMemoryStore.java
Log:
Commit efficient MRU store implementation before it gets completely lost
Revision Changes Path
1.3 +42 -51
cocoon-2.1/src/deprecated/java/org/apache/cocoon/components/store/MRUMemoryStore.java
Index: MRUMemoryStore.java
===================================================================
RCS file:
/home/cvs/cocoon-2.1/src/deprecated/java/org/apache/cocoon/components/store/MRUMemoryStore.java,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -r1.2 -r1.3
--- MRUMemoryStore.java 27 Apr 2003 15:16:15 -0000
1.2
+++ MRUMemoryStore.java 27 Apr 2003 16:41:31 -0000
1.3
@@ -61,21 +61,24 @@
import org.apache.avalon.framework.thread.ThreadSafe;
import org.apache.cocoon.util.ClassUtils;
+import org.apache.cocoon.util.MRUBucketMap;
import java.io.IOException;
import java.net.URLEncoder;
import java.util.Enumeration;
-import java.util.Hashtable;
-import java.util.LinkedList;
import java.util.NoSuchElementException;
+import java.util.Iterator;
+import java.util.Map;
/**
* This class provides a cache algorithm for the requested documents.
* It combines a HashMap and a LinkedList to create a so called MRU
* (Most Recently Used) cache.
*
- * The idea was taken from the "Writing Advanced Application Tutorial"
from
- * javasoft. Many thanx to the writers!
+ * <p>This implementation is based on MRUBucketMap - map with efficient
+ * O(1) implementation of MRU removal policy.
+ *
+ * <p>TODO: Port improvments to the Excalibur implementation
*
* @deprecated Use the Avalon Excalibur Store instead.
*
@@ -89,8 +92,7 @@
private int maxobjects;
private boolean persistent;
- private Hashtable cache;
- private LinkedList mrulist;
+ private MRUBucketMap cache;
private Store persistentStore;
private StoreJanitor storeJanitor;
private ComponentManager manager;
@@ -129,8 +131,7 @@
throw new ParameterException("MRUMemoryStore maxobjects must
be at least 1!");
}
- this.cache = new Hashtable((int)(this.maxobjects * 1.2));
- this.mrulist = new LinkedList();
+ this.cache = new MRUBucketMap((int)(this.maxobjects * 1.2));
this.storeJanitor.register(this);
}
@@ -151,12 +152,8 @@
if (getLogger().isDebugEnabled()) {
getLogger().debug("Final cache size: " +
this.cache.size());
}
- Enumeration enum = this.cache.keys();
- while (enum.hasMoreElements()) {
- Object key = enum.nextElement();
- if (key == null) {
- continue;
- }
+ for (Iterator i = this.cache.keySet().iterator();
i.hasNext(); ) {
+ Object key = i.next();
try {
Object value = this.cache.remove(key);
if(checkSerializable(value)) {
@@ -183,7 +180,7 @@
* @param key The key for the object to store
* @param value The object to store
*/
- public synchronized void store(Object key, Object value) {
+ public void store(Object key, Object value) {
this.hold(key,value);
}
@@ -195,21 +192,21 @@
* @param key The key of the object to be stored
* @param value The object to be stored
*/
- public synchronized void hold(Object key, Object value) {
+ public void hold(Object key, Object value) {
if (getLogger().isDebugEnabled()) {
getLogger().debug("Holding object in memory:");
getLogger().debug(" key: " + key);
getLogger().debug(" value: " + value);
}
+
/** ...first test if the max. objects in cache is reached... */
- while (this.mrulist.size() >= this.maxobjects) {
+ while (this.cache.size() >= this.maxobjects) {
/** ...ok, heapsize is reached, remove the last element...
*/
this.free();
}
+
/** ..put the new object in the cache, on the top of course ...
*/
this.cache.put(key, value);
- this.mrulist.remove(key);
- this.mrulist.addFirst(key);
}
/**
@@ -218,12 +215,9 @@
* @param key The key of the requested object
* @return the requested object
*/
- public synchronized Object get(Object key) {
+ public Object get(Object key) {
Object value = this.cache.get(key);
if (value != null) {
- /** put the accessed key on top of the linked list */
- this.mrulist.remove(key);
- this.mrulist.addFirst(key);
if (getLogger().isDebugEnabled()) {
getLogger().debug("Found key: " + key.toString());
}
@@ -239,12 +233,10 @@
value = this.persistentStore.get(getFileName(key.toString
()));
if (value != null) {
try {
- if(!this.cache.containsKey(key)) {
- this.hold(key, value);
- }
+ this.hold(key, value);
return value;
} catch (Exception e) {
- getLogger().error("Error in get()!", e);
+ getLogger().error("Error in hold()!", e);
return null;
}
}
@@ -258,13 +250,12 @@
*
* @param key The key of to be removed object
*/
- public synchronized void remove(Object key) {
+ public void remove(Object key) {
if (getLogger().isDebugEnabled()) {
getLogger().debug("Removing object from store");
getLogger().debug(" key: " + key);
}
this.cache.remove(key);
- this.mrulist.remove(key);
if(this.persistent && key != null) {
this.persistentStore.remove(getFileName(key.toString()));
}
@@ -276,12 +267,8 @@
* @param key The key of the object
* @return true if the key exists
*/
- public synchronized boolean containsKey(Object key) {
- if(persistent) {
- return (cache.containsKey(key) ||
persistentStore.containsKey(key));
- } else {
- return cache.containsKey(key);
- }
+ public boolean containsKey(Object key) {
+ return cache.containsKey(key) || (persistent &&
persistentStore.containsKey(key));
}
/**
@@ -289,15 +276,25 @@
*
* @return the enumeration of the cache
*/
- public synchronized Enumeration keys() {
- return this.cache.keys();
+ public Enumeration keys() {
+ return new Enumeration() {
+ private Iterator i = cache.keySet().iterator();
+
+ public boolean hasMoreElements() {
+ return i.hasNext();
+ }
+
+ public Object nextElement() {
+ return i.next();
+ }
+ };
}
/**
* Returns count of the objects in the store, or -1 if could not be
* obtained.
*/
- public synchronized int size() {
+ public int size() {
return this.cache.size();
}
@@ -305,28 +302,23 @@
* Frees some of the fast memory used by this store.
* It removes the last element in the store.
*/
- public synchronized void free() {
+ public void free() {
try {
if (this.cache.size() > 0) {
// This can throw NoSuchElementException
- Object key = this.mrulist.removeLast();
- Object value = this.cache.remove(key);
- if (value == null) {
- getLogger().warn("Concurrency condition in free()");
- }
-
+ Map.Entry node = this.cache.removeLast();
if (getLogger().isDebugEnabled()) {
getLogger().debug("Freeing cache.");
- getLogger().debug(" key: " + key);
- getLogger().debug(" value: " + value);
+ getLogger().debug(" key: " + node.getKey());
+ getLogger().debug(" value: " + node.getValue());
}
if (this.persistent) {
// Swap object on fs.
- if(checkSerializable(value)) {
+ if(checkSerializable(node.getValue())) {
try {
this.persistentStore.store(
- getFileName(key.toString()), value);
+ getFileName(node.getKey().toString()),
node.getValue());
} catch(Exception e) {
getLogger().error("Error storing object on
fs", e);
}
@@ -377,4 +369,3 @@
return URLEncoder.encode(key.toString());
}
}
-