X-Git-Url: http://wamblee.org/gitweb/?a=blobdiff_plain;f=support%2Fgeneral%2Fsrc%2Fmain%2Fjava%2Forg%2Fwamblee%2Fcache%2FCachedObject.java;h=bdabd51795a92787893ed87c862827a8eb754586;hb=ddd261f331280640c5b53c7128230b629ebcd268;hp=58daf8c918ee3c53ff4ade7d31db0ee9d90fe279;hpb=32a62ca2c752e33a7873ac868a7a1f289caedcd4;p=utils

diff --git a/support/general/src/main/java/org/wamblee/cache/CachedObject.java b/support/general/src/main/java/org/wamblee/cache/CachedObject.java
index 58daf8c9..bdabd517 100644
--- a/support/general/src/main/java/org/wamblee/cache/CachedObject.java
+++ b/support/general/src/main/java/org/wamblee/cache/CachedObject.java
@@ -1,71 +1,60 @@
 /*
  * Copyright 2005 the original author or authors.
- * 
+ *
  * Licensed 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.wamblee.cache;
 
+import org.apache.log4j.Logger;
+
 import java.io.Serializable;
 
-import org.apache.log4j.Logger;
 
 /**
- * Represents a cached object. The object is either retrieved from the cache if
- * the cache has it, or a call back is invoked to get the object (and put it in
- * the cache).
+ * Represents a cached object. The object is either retrieved from the
+ * cache if the cache has it, or a call back is invoked to get the object (and
+ * put it in the cache).
  *
  * @author Erik Brakkee
+ *
+ * @param <KeyType> DOCUMENT ME!
+ * @param <ValueType> DOCUMENT ME!
  */
 public class CachedObject<KeyType extends Serializable, ValueType extends Serializable> {
-
-    private static final Logger LOGGER = Logger.getLogger(CachedObject.class);
-
     /**
-     * Callback invoked to compute an object if it was not found in the cache.
-     * 
-     * @param <T>
-     *            Type of the object
+     * DOCUMENT ME!
      */
-    public static interface Computation<Key extends Serializable, Value extends Serializable> {
-        /**
-         * Gets the object. Called when the object is not in the cache.
-         * 
-         * @param aObjectKey
-         *            Id of the object in the cache.
-         * @return Object, must be non-null.
-         */
-        Value getObject(Key aObjectKey);
-    }
+    private static final Logger LOGGER = Logger.getLogger(CachedObject.class);
 
     /**
      * Cache to use.
      */
-    private Cache<KeyType, ValueType> _cache;
+    private Cache<KeyType, ValueType> cache;
 
     /**
      * Key of the object in the cache.
      */
-    private KeyType _objectKey;
+    private KeyType objectKey;
 
     /**
-     * Computation used to obtain the object if it is not found in the cache.
+     * Computation used to obtain the object if it is not found in the
+     * cache.
      */
-    private Computation<KeyType, ValueType> _computation;
+    private Computation<KeyType, ValueType> computation;
 
-    /**
+/**
      * Constructs the cached object.
-     * 
+     *
      * @param aCache
      *            Cache to use.
      * @param aObjectKey
@@ -75,22 +64,23 @@ public class CachedObject<KeyType extends Serializable, ValueType extends Serial
      *            cache.
      */
     public CachedObject(Cache<KeyType, ValueType> aCache, KeyType aObjectKey,
-            Computation<KeyType, ValueType> aComputation) {
-        _cache = aCache;
-        _objectKey = aObjectKey;
-        _computation = aComputation;
+        Computation<KeyType, ValueType> aComputation) {
+        cache           = aCache;
+        objectKey       = aObjectKey;
+        computation     = aComputation;
     }
 
     /**
-     * Gets the object. Since the object is cached, different calls to this
-     * method may return different objects.
-     * 
+     * Gets the object. Since the object is cached, different calls to
+     * this method may return different objects.
+     *
      * @return Object.
      */
     public ValueType get() {
-        ValueType object = (ValueType) _cache.get(_objectKey); // the used
-                                                                // cache is
-                                                                // thread safe.
+        ValueType object = (ValueType) cache.get(objectKey); // the used
+                                                             // cache is
+                                                             // thread safe.
+
         if (object == null) {
             // synchronize the computation to make sure that the object is only
             // computed
@@ -98,34 +88,53 @@ public class CachedObject<KeyType extends Serializable, ValueType extends Serial
             // be
             // recomputed.
             synchronized (this) {
-                object = (ValueType) _cache.get(_objectKey);
+                object = (ValueType) cache.get(objectKey);
+
                 if (object == null) {
                     // No other thread did a recomputation so we must do this
                     // now.
-                    LOGGER.debug("Refreshing cache for '" + _objectKey + "'");
-                    object = _computation.getObject(_objectKey);
-                    _cache.put(_objectKey, object);
+                    LOGGER.debug("Refreshing cache for '" + objectKey + "'");
+                    object = computation.getObject(objectKey);
+                    cache.put(objectKey, object);
                 }
             }
         }
+
         return object;
     }
 
     /**
-     * Invalidates the cache for the object so that it is recomputed the next
-     * time it is requested.
-     * 
+     * Invalidates the cache for the object so that it is recomputed
+     * the next time it is requested.
      */
     public void invalidate() {
-        _cache.remove(_objectKey);
+        cache.remove(objectKey);
     }
 
     /**
      * Gets the cache.
-     * 
+     *
      * @return Cache.
      */
     public Cache getCache() {
-        return _cache;
+        return cache;
+    }
+
+/**
+     * Callback invoked to compute an object if it was not found in the cache.
+     *
+     * @param <T>
+     *            Type of the object
+     */
+    public static interface Computation<Key extends Serializable, Value extends Serializable> {
+        /**
+         * Gets the object. Called when the object is not in the
+         * cache.
+         *
+         * @param aObjectKey Id of the object in the cache.
+         *
+         * @return Object, must be non-null.
+         */
+        Value getObject(Key aObjectKey);
     }
 }