--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/gov/nasa/jpf/search/heuristic/SimplePriorityHeuristic.java	Fri Jan 23 10:14:01 2015 -0800
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2014, United States Government, as represented by the
+ * Administrator of the National Aeronautics and Space Administration.
+ * All rights reserved.
+ *
+ * The Java Pathfinder core (jpf-core) platform is 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.
+ */
+
+package gov.nasa.jpf.search.heuristic;
+
+import gov.nasa.jpf.Config;
+import gov.nasa.jpf.util.Predicate;
+import gov.nasa.jpf.vm.ThreadInfo;
+import gov.nasa.jpf.vm.VM;
+
+/**
+ * a heuristic that is based on static priorities that are determined
+ * at state storage time
+ */
+public abstract class SimplePriorityHeuristic extends HeuristicSearch {
+
+  StaticPriorityQueue queue;
+  
+  protected Predicate<ThreadInfo> aliveThread;
+  
+  public SimplePriorityHeuristic (Config config, VM vm) {
+    super(config,vm);
+
+    queue = new StaticPriorityQueue(config);
+    
+    aliveThread = new Predicate<ThreadInfo>() {
+      @Override
+	public boolean isTrue (ThreadInfo ti) {
+        return (ti.isAlive());
+      }
+    };
+    
+  }
+
+  protected abstract int computeHeuristicValue ();
+
+  protected int computeAstarPathCost (VM vm) {
+    return vm.getPathLength();
+  }
+  
+  @Override
+  protected HeuristicState queueCurrentState () {
+    int heuristicValue;
+    
+    if (vm.isInterestingState()) {
+      heuristicValue = 0;
+    } else if (vm.isBoringState()) {
+      heuristicValue = Integer.MAX_VALUE;
+      
+    } else {
+      heuristicValue = computeHeuristicValue();
+      
+      if (useAstar) {
+        // <2do> we probably don't want this for isInteresting/isBoring?
+        heuristicValue += computeAstarPathCost(vm);
+      }
+    }
+    
+    PrioritizedState hState = new PrioritizedState(vm,heuristicValue);
+    
+    queue.add(hState);
+    
+    return hState;
+  }
+  
+  @Override
+  protected HeuristicState getNextQueuedState () {
+    
+    //HeuristicState hState = queue.pollFirst();  // only Java 1.6
+    //if (isBeanSearch) { queue.clear(); }
+    //return hState;
+
+    if (queue.size() == 0) {                      // the dreaded Java 1.5 version
+      return null;
+    }
+    HeuristicState hState = queue.first();
+    
+    if (isBeamSearch) {
+      queue.clear();
+    } else {
+      queue.remove(hState);      
+    }
+    
+    return hState;
+  }
+
+  @Override
+  public int getQueueSize() {
+    return queue.size();
+  }
+  
+  @Override
+  public boolean isQueueLimitReached() {
+    return queue.isQueueLimitReached();
+  }
+}