1 files changed, 105 insertions, 0 deletions
diff --git a/src/main/java/org/cristalise/kernel/utils/DescriptionObjectCache.java b/src/main/java/org/cristalise/kernel/utils/DescriptionObjectCache.java
new file mode 100644
index 0000000..e5d0252
--- /dev/null
+++ b/src/main/java/org/cristalise/kernel/utils/DescriptionObjectCache.java
@@ -0,0 +1,105 @@
+/**
+ * This file is part of the CRISTAL-iSE kernel.
+ * Copyright (c) 2001-2014 The CRISTAL Consortium. All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; with out even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * http://www.fsf.org/licensing/licenses/lgpl.html
+ */
+/**
+ *
+ */
+package org.cristalise.kernel.utils;
+
+import org.cristalise.kernel.common.InvalidDataException;
+import org.cristalise.kernel.common.ObjectNotFoundException;
+import org.cristalise.kernel.entity.proxy.ItemProxy;
+import org.cristalise.kernel.entity.proxy.MemberSubscription;
+import org.cristalise.kernel.entity.proxy.ProxyObserver;
+import org.cristalise.kernel.persistency.ClusterStorage;
+import org.cristalise.kernel.persistency.outcome.Viewpoint;
+
+
+public abstract class DescriptionObjectCache<D extends DescriptionObject> {
+
+	SoftCache<String, CacheEntry<D>> cache = new SoftCache<String, CacheEntry<D>>();
+
+	public D get(String name, int version) throws ObjectNotFoundException, InvalidDataException {
+		D thisDef;
+		synchronized(cache) {
+			CacheEntry<D> thisDefEntry = cache.get(name+"_"+version);
+			if (thisDefEntry == null) {
+				Logger.msg(6, name+" v"+version+" not found in cache. Retrieving.");
+		        ItemProxy defItem = LocalObjectLoader.loadLocalObjectDef(getDefRoot(), name);
+		        thisDef = loadObject(name, version, defItem);
+		        cache.put(name+"_"+version, new CacheEntry<D>(thisDef, defItem, this));
+			}
+			else {
+				Logger.msg(6, name+" v"+version+" found in cache.");
+				thisDef = thisDefEntry.def;
+			}
+		}
+        return thisDef;
+	}
+	
+	public abstract String getDefRoot();
+	
+	public abstract D loadObject(String name, int version, ItemProxy proxy) throws ObjectNotFoundException, InvalidDataException;
+
+	public void removeObject(String id) {
+		synchronized(cache) {
+		if (cache.keySet().contains(id)) {
+			Logger.msg(7, "ActDefCache: Removing activity def "+id+" from cache");
+			cache.remove(id);
+			}
+		}
+	}
+
+	public class CacheEntry<E extends DescriptionObject> implements ProxyObserver<Viewpoint> {
+		public String id;
+		public ItemProxy proxy;
+		public E def;
+		public DescriptionObjectCache<E> parent;
+		public CacheEntry(E def, ItemProxy proxy, DescriptionObjectCache<E> parent) {
+			this.id = def.getName()+"_"+def.getVersion();
+			this.def = def;
+			this.parent = parent;
+			this.proxy = proxy;
+			proxy.subscribe(new MemberSubscription<Viewpoint>(this, ClusterStorage.VIEWPOINT, false));
+		}
+		@Override
+		public void finalize() {
+			parent.removeObject(id);
+			proxy.unsubscribe(this);
+		}
+		@Override
+		public void add(Viewpoint contents) {
+			parent.removeObject(id);
+		}
+
+		@Override
+		public void remove(String oldId) {
+			parent.removeObject(oldId);
+		}
+
+		@Override
+		public String toString() {
+			return "Cache entry: "+id;
+		}
+		@Override
+		public void control(String control, String msg) {
+		}
+	}
+}
+\ No newline at end of file