ALF-9613: numerous changes including use of ReentrantReadWriteLock for locking and introduction of a custom cleanup job that does not delete files that are in use by the cache.

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@30066 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/content/caching/Key.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2005-2011 Alfresco Software Limited.
+ *
+ * This file is part of Alfresco
+ *
+ * Alfresco 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.
+ *
+ * Alfresco is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without 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 Alfresco. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.alfresco.repo.content.caching;
+
+import java.io.File;
+import java.io.Serializable;
+
+/**  
+ * Multipurpose key so that data can be cached either by content URL or cache file path.
+ * 
+ * @author Matt Ward
+ */
+public class Key implements Serializable
+{
+    private static final long serialVersionUID = 1L;
+    private enum Type { CONTENT_URL, CACHE_FILE_PATH };
+    private final Type type;
+    private final String value;
+    
+    private Key(Type type, String value)
+    {
+        this.type = type;
+        this.value = value;
+    }
+    
+    public static Key forUrl(String url)
+    {
+        return new Key(Type.CONTENT_URL, url);
+    }
+    
+    public static Key forCacheFile(String path)
+    {
+        return new Key(Type.CACHE_FILE_PATH, path);
+    }
+    
+    public static Key forCacheFile(File file)
+    {
+        return forCacheFile(file.getAbsolutePath());
+    }
+
+    @Override
+    public int hashCode()
+    {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((this.type == null) ? 0 : this.type.hashCode());
+        result = prime * result + ((this.value == null) ? 0 : this.value.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj)
+    {
+        if (this == obj) return true;
+        if (obj == null) return false;
+        if (getClass() != obj.getClass()) return false;
+        Key other = (Key) obj;
+        if (this.type != other.type) return false;
+        if (this.value == null)
+        {
+            if (other.value != null) return false;
+        }
+        else if (!this.value.equals(other.value)) return false;
+        return true;
+    }
+}