initial version of support project with build support.

[utils] / src / org / wamblee / cache / EhCache.java

diff --git a/src/org/wamblee/cache/EhCache.java b/src/org/wamblee/cache/EhCache.java
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+++ b/src/org/wamblee/cache/EhCache.java
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+/*
+ * 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 java.io.IOException;
+import java.io.InputStream;
+import java.io.Serializable;
+
+import net.sf.ehcache.Cache;
+import net.sf.ehcache.CacheException;
+import net.sf.ehcache.CacheManager;
+import net.sf.ehcache.Element;
+
+import org.apache.log4j.Logger;
+import org.wamblee.io.InputResource;
+
+/**
+ * Cache implemented on top of EhCache.
+ */
+public class EhCache<KeyType extends Serializable, ValueType extends Serializable>
+        implements org.wamblee.cache.Cache<KeyType, ValueType> {
+
+    private static final Logger LOGGER = Logger.getLogger(EhCache.class);
+    
+    /**
+     * EH Cache manager. 
+     */
+    private CacheManager _manager;
+
+    /**
+     * EH cache. 
+     */
+    private Cache _cache;
+
+    /**
+     * Constructs a cache based on EHCache. 
+     * @param aResource Resource containing the configuration file for 
+     *    EHCache. 
+     * @param aCacheName Name of the cache to use. If a cache with this name does 
+     *    not exist, one is created based on default settings. 
+     * @throws IOException
+     * @throws CacheException
+     */
+    public EhCache(InputResource aResource, String aCacheName)
+            throws IOException, CacheException {
+        InputStream is = aResource.getInputStream();
+        try {
+            _manager = CacheManager.create();
+            _cache = _manager.getCache(aCacheName);
+            if (_cache == null) {
+                LOGGER.warn("Creating cache '" + aCacheName + "' because it is not configured");;
+                _manager.addCache(aCacheName);
+                _cache = _manager.getCache(aCacheName);
+            }
+            assert _cache != null; 
+        } finally {
+            is.close();
+        }
+
+    }
+
+    /*
+     * (non-Javadoc)
+     * 
+     * @see org.wamblee.cache.Cache#put(KeyType, ValueType)
+     */
+    public void put(KeyType aKey, ValueType aValue) {
+        _cache.put(new Element(aKey, aValue));
+    }
+
+    /*
+     * (non-Javadoc)
+     * 
+     * @see org.wamblee.cache.Cache#get(KeyType)
+     */
+    public ValueType get(KeyType aKey) {
+        try {
+            Element element =  _cache.get(aKey);
+            if ( element == null ) { 
+                return null; 
+            }
+            return (ValueType)element.getValue();
+        } catch (CacheException e) {
+            throw new RuntimeException("Cache problem key = '" + aKey + "'", e);
+        }
+    }
+
+    /*
+     * (non-Javadoc)
+     * 
+     * @see org.wamblee.cache.Cache#remove(KeyType)
+     */
+    public void remove(KeyType aKey) {
+        _cache.remove(aKey);
+    }
+
+    /*
+     * (non-Javadoc)
+     * 
+     * @see org.wamblee.cache.Cache#clear()
+     */
+    public void clear() {
+        try {
+            _cache.removeAll();
+        } catch (IOException e) {
+            throw new RuntimeException("Problem removing items from cache", e);
+        }
+    }
+}