--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/dancres/blitz/arc/CacheBlockDescriptor.java	Sat Mar 21 11:00:06 2009 +0000
@@ -0,0 +1,93 @@
+package org.dancres.blitz.arc;
+
+import java.util.logging.Level;
+
+import java.io.Serializable;
+
+import EDU.oswego.cs.dl.util.concurrent.Mutex;
+
+import org.dancres.struct.LinkedInstance;
+
+import org.dancres.blitz.cache.Identifiable;
+import org.dancres.blitz.cache.Identifier;
+import org.dancres.blitz.cache.CacheListenerSet;
+
+/**
+   Each object currently in cache is referenced via a CacbeBlockDescriptor
+ */
+public class CacheBlockDescriptor implements LinkedInstance {
+    private Identifier theIdentifier;
+    private Identifiable theContent;
+
+    private LinkedInstance thePrev;
+    private LinkedInstance theNext;
+
+    private int isWhere;
+
+    private Mutex theLock = new Mutex();
+
+    CacheBlockDescriptor() {
+    }
+
+    void acquire() throws InterruptedException {
+        theLock.acquire();
+    }
+
+    public void release() {
+        theLock.release();
+    }
+
+    public void setId(Identifier anIdentifier) {
+        theIdentifier = anIdentifier;
+    }
+
+    public Identifier getId() {
+        return theIdentifier;
+    }
+
+    public Identifiable getContent() {
+        return theContent;
+    }
+ 
+    void setContent(Identifiable aContent) {
+        theContent = aContent;
+    }
+
+    public void setNext(LinkedInstance aLinkedInstance) {
+        theNext = aLinkedInstance;
+    }
+
+    public LinkedInstance getNext() {
+        return theNext;
+    }
+
+    public void setPrev(LinkedInstance aLinkedInstance) {
+        thePrev = aLinkedInstance;
+    }
+
+    public LinkedInstance getPrev() {
+        return thePrev;
+    }
+
+    boolean isEmpty() {
+        return (theContent == null);
+    }
+
+    /**
+       Marks the CBD as being on a particular list, T1, T2, B1 or B2.
+
+       @see org.dancres.blitz.arc.Lru
+     */
+    void setWhere(int aWhere) {
+        isWhere = aWhere;
+    }
+
+    /**
+       Returns an indication of which list this CBD is on, T1, T2, B1 or B2.
+
+       @see org.dancres.blitz.arc.Lru
+     */
+    int getWhere() {
+        return isWhere;
+    }
+}