Merge branch 'master' of feistymeow.org:feisty_meow

[feisty_meow.git] / kona / src / org / gffs / cache / CacheList.java

diff --git a/kona/src/org/gffs/cache/CacheList.java b/kona/src/org/gffs/cache/CacheList.java
new file mode 100644 (file)
index 0000000..dc2d213
--- /dev/null
+++ b/kona/src/org/gffs/cache/CacheList.java
@@ -0,0 +1,77 @@
+package org.gffs.cache;
+
+/*
+ * Copyright 2006 University of Virginia
+ * 
+ * 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.
+ */
+
+abstract class CacheList<KeyType, DataType>
+{
+       protected int _myRole;
+
+       protected RoleBasedCacheNode<KeyType, DataType> _head;
+       protected RoleBasedCacheNode<KeyType, DataType> _tail;
+
+       protected CacheList(int role)
+       {
+               _myRole = role;
+
+               _head = _tail = null;
+       }
+
+       public abstract void insert(RoleBasedCacheNode<KeyType, DataType> node);
+
+       public RoleBasedCacheNode<KeyType, DataType> removeFirst()
+       {
+               if (_head == null)
+                       return null;
+
+               RoleBasedCacheNode<KeyType, DataType> ret = _head;
+
+               _head = _head.getNext(_myRole);
+               if (_head != null)
+                       _head.setPrevious(_myRole, null);
+               else
+                       _tail = null;
+
+               ret.clearLinks(_myRole);
+               return ret;
+       }
+
+       public RoleBasedCacheNode<KeyType, DataType> peekFirst()
+       {
+               if (_head == null)
+                       return null;
+
+               return _head;
+       }
+
+       public void remove(RoleBasedCacheNode<KeyType, DataType> node)
+       {
+               if (node.getPrevious(_myRole) == null) // At the head of the list
+                       _head = node.getNext(_myRole);
+               else
+                       node.getPrevious(_myRole).setNext(_myRole, node.getNext(_myRole));
+
+               if (node.getNext(_myRole) == null) // At the tail of the list
+                       _tail = node.getPrevious(_myRole);
+               else
+                       node.getNext(_myRole).setPrevious(_myRole, node.getPrevious(_myRole));
+
+               node.clearLinks(_myRole);
+       }
+
+       public void clear()
+       {
+               _head = null;
+               _tail = null;
+       }
+}
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