# HG changeset patch
# User Jaroslav Tulach <jtulach@netbeans.org>
# Date 1234332761 -3600
# Node ID 41a4abecb6008f97de7e4df3ae187ec97af87ee5
# Parent  08dd52950883b13f6462fd95952369f1808be81d
Rewritten to rely on (private) synchronized methods

diff -r 08dd52950883 -r 41a4abecb600 samples/deadlock/src/org/apidesign/javamonitorflaws/Cache.java
--- a/samples/deadlock/src/org/apidesign/javamonitorflaws/Cache.java	Tue Feb 10 18:36:21 2009 +0100
+++ b/samples/deadlock/src/org/apidesign/javamonitorflaws/Cache.java	Wed Feb 11 07:12:41 2009 +0100
@@ -3,38 +3,44 @@
 import java.util.HashMap;
 import java.util.Map;
 
-/**
+/** Classical caching support class that makes sure there is
+ * always one "To" value for each "From" one returned from the {@link #get}
+ * method. However it does not prevent multiple threads to call
+ * {@link #createItem} multiple times for the same "From" value.
+ * <p>
+ *
  *
  * @author Jaroslav Tulach <jtulach@netbeans.org>
  */
 public abstract class Cache<From,To> {
     private Map<From,To> cache;
 
+    protected abstract To createItem(From f);
+
     public final To get(From f) {
-        for (;;) {
-            synchronized (this) {
-                if (cache == null) {
-                    cache = new HashMap<From, To>();
-                }
-                To t = cache.get(f);
-                if (t != null) {
-                    return t;
-                }
-            }
+        To t = inspectValue(f);
+        if (t != null) {
+            return t;
+        }
+        To newT = createItem(f);
+        return registerValue(f, newT);
+    }
 
-            To newT = createItem(f);
 
-            synchronized (this) {
-                To t = cache.get(f);
-                if (t == null) {
-                    cache.put(f, newT);
-                    return newT;
-                } else {
-                    return t;
-                }
-            }
+    private synchronized To inspectValue(From f) {
+        if (cache == null) {
+            cache = new HashMap<From, To>();
+        }
+        return cache.get(f);
+    }
+
+    private synchronized To registerValue(From f, To newT) {
+        To t = cache.get(f);
+        if (t == null) {
+            cache.put(f, newT);
+            return newT;
+        } else {
+            return t;
         }
     }
-
-    protected abstract To createItem(From f);
 }
diff -r 08dd52950883 -r 41a4abecb600 samples/deadlock/test/org/apidesign/javamonitorflaws/MultiplyCache.java
--- a/samples/deadlock/test/org/apidesign/javamonitorflaws/MultiplyCache.java	Tue Feb 10 18:36:21 2009 +0100
+++ b/samples/deadlock/test/org/apidesign/javamonitorflaws/MultiplyCache.java	Wed Feb 11 07:12:41 2009 +0100
@@ -28,7 +28,7 @@
         }
         pcs.addPropertyChangeListener(listener);
     }
-    public void removePropertyChangeListener(PropertyChangeListener listener) {
+    public synchronized void removePropertyChangeListener(PropertyChangeListener listener) {
         if (pcs != null) {
             pcs.removePropertyChangeListener(listener);
         }