Freeze facet update

1 files changed, 132 insertions, 0 deletions

diff --git a/java/src/IceUtil/Cache.java b/java/src/IceUtil/Cache.java
new file mode 100644
index 00000000000..feb7a789b53
--- /dev/null
+++ b/java/src/IceUtil/Cache.java
@@ -0,0 +1,132 @@
+// **********************************************************************
+//
+// Copyright (c) 2004
+// ZeroC, Inc.
+// Billerica, MA, USA
+//
+// All Rights Reserved.
+//
+// Ice is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License version 2 as published by
+// the Free Software Foundation.
+//
+// **********************************************************************
+
+package IceUtil;
+
+//
+// An abstraction to efficiently populate a Cache, without holding
+// a lock while loading from a database.
+//
+// TODO: implement efficiently!
+//
+
+public class Cache
+{
+    public Cache(Store store)
+    {
+	_store = store;
+    }
+    
+    public Object 
+    getIfPinned(Object key)
+    {
+	synchronized(_map)
+	{
+	    return _map.get(key);
+	}
+    }
+    
+    public Object
+    pin(Object key)
+    {
+	synchronized(_map)
+	{
+	    Object o = _map.get(key);
+	    if(o == null)
+	    {
+		o = _store.load(key);
+		if(o != null)
+		{
+		    _map.put(key, o);
+		}
+	    }
+	    return o;
+	}
+    }
+
+    public Object
+    unpin(Object key)
+    {
+	synchronized(_map)
+	{
+	    return _map.remove(key);
+	}
+    }
+
+    public void
+    clear()
+    {
+	synchronized(_map)
+	{
+	    _map.clear();
+	}
+    }
+    
+    public int
+    size()
+    {
+	synchronized(_map)
+	{
+	    return _map.size();
+	}
+    }
+
+    public Object
+    add(Object key, Object value)
+    {
+	assert value != null;
+
+	synchronized(_map)
+	{
+	    Object existingVal = _map.put(key, value);
+	    if(existingVal != null)
+	    {
+		_map.put(key, existingVal);
+		return existingVal;
+	    }
+	    
+	    //
+	    // Let's check if it's in the store
+	    //
+	    existingVal = _store.load(key);
+	    if(existingVal != null)
+	    {
+		_map.put(key, existingVal);
+		return existingVal;
+	    }
+	    else
+	    {
+		return null;
+	    }
+	}
+    }
+
+    public Object
+    pin(Object key, Object value)
+    {
+	synchronized(_map)
+	{
+	    Object existingVal = _map.put(key, value);
+	    if(existingVal != null)
+	    {
+		_map.put(key, existingVal);
+	    }
+	    return existingVal;
+	}
+    }
+
+    private final java.util.Map _map = new java.util.HashMap();
+    private final Store _store;
+
+}