Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.utils.datastructures / src / org / simantics / utils / datastructures / cache / CachedMapProvider.java

diff --git a/bundles/org.simantics.utils.datastructures/src/org/simantics/utils/datastructures/cache/CachedMapProvider.java b/bundles/org.simantics.utils.datastructures/src/org/simantics/utils/datastructures/cache/CachedMapProvider.java
new file mode 100644 (file)
index 0000000..aefc753
--- /dev/null
+++ b/bundles/org.simantics.utils.datastructures/src/org/simantics/utils/datastructures/cache/CachedMapProvider.java
@@ -0,0 +1,116 @@
+/*******************************************************************************\r
+ * Copyright (c) 2007, 2010 Association for Decentralized Information Management\r
+ * in Industry THTH ry.\r
+ * All rights reserved. This program and the accompanying materials\r
+ * are made available under the terms of the Eclipse Public License v1.0\r
+ * which accompanies this distribution, and is available at\r
+ * http://www.eclipse.org/legal/epl-v10.html\r
+ *\r
+ * Contributors:\r
+ *     VTT Technical Research Centre of Finland - initial API and implementation\r
+ *******************************************************************************/\r
+/*\r
+ *\r
+ * @author Toni Kalajainen\r
+ */\r
+package org.simantics.utils.datastructures.cache;\r
+\r
+import java.util.HashMap;\r
+import java.util.Map;\r
+import java.util.Set;\r
+\r
+import org.simantics.utils.datastructures.disposable.AbstractDisposable;\r
+\r
+/**\r
+ * CachedProvider provides values and stores the results in a cache.\r
+ * Cached values must be explicitly released with clear, retain or remove.\r
+ * Values are held with strong references.\r
+ *\r
+ * @param <K> the key\r
+ * @param <V> the value\r
+ */\r
+public class CachedMapProvider<K, V> extends AbstractDisposable implements IMapProvider<K, V> {\r
+\r
+       private Map<K, V> cache;\r
+       \r
+       private final IMapProvider<K, V> provider;\r
+       \r
+       /**\r
+        * Constructs new strong cache\r
+        * \r
+        * @param provider provider of values\r
+        */\r
+       public CachedMapProvider(IMapProvider<K, V> provider)\r
+       {\r
+               assert(provider!=null);\r
+               this.provider = provider;\r
+               this.cache = new HashMap<K, V>();\r
+       }               \r
+\r
+       /**\r
+        * Constructs new strong cache\r
+        * \r
+        * @param provider provider of values\r
+        * @param cacheMap the map to use\r
+        */\r
+       public CachedMapProvider(IMapProvider<K, V> provider, Map<K, V> cacheMap)\r
+       {\r
+               assert(provider!=null);\r
+               this.provider = provider;\r
+               this.cache = cacheMap;\r
+       }               \r
+       \r
+       @Override\r
+       public synchronized V get(K key) {\r
+               assertNotDisposed();\r
+               V value = cache.get(key);\r
+               if (value!=null) return value;\r
+               value = provider.get(key);\r
+               assert(value!=null);\r
+               cache.put(key, value);                  \r
+               return value;\r
+       }\r
+       \r
+       public synchronized void clear()\r
+       {\r
+               cache.clear();\r
+       }\r
+       \r
+       public synchronized void retain(Set<K> keys)\r
+       {\r
+               cache.keySet().retainAll(keys);\r
+       }\r
+\r
+       public synchronized void remove(Set<K> keys)\r
+       {\r
+               cache.keySet().removeAll(keys);\r
+       }\r
+       \r
+       public synchronized void load(Set<K> keys)\r
+       {\r
+               for (K key : keys)\r
+                       get(key);\r
+       }\r
+       \r
+       public synchronized void addAll(CachedMapProvider<K, V> anotherCache)\r
+       {\r
+               assertNotDisposed();\r
+               cache.putAll(anotherCache.cache);\r
+       }       \r
+       \r
+       public IMapProvider<K, V> getProvider() {\r
+               return provider;\r
+       }\r
+       \r
+       public synchronized Map<K, V> getAll()\r
+       {\r
+               assertNotDisposed();\r
+               return new HashMap<K, V>(cache);\r
+       }\r
+\r
+       @Override\r
+       protected void doDispose() {\r
+               clear();\r
+       }\r
+       \r
+}\r