--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/gov/nasa/jpf/vm/ThresholdFieldLockInfo.java	Fri Jan 23 10:14:01 2015 -0800
@@ -0,0 +1,61 @@
+/*
+ * 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.vm;
+
+import gov.nasa.jpf.JPFException;
+
+/**
+ * a FieldLockInfo that assumes lock protection after n accesses with
+ * non-empty lock sets
+ */
+public abstract class ThresholdFieldLockInfo extends FieldLockInfo implements Cloneable {
+  protected int remainingChecks;
+
+  protected ThresholdFieldLockInfo(int remainingChecks) {
+    this.remainingChecks = remainingChecks;
+  }
+
+  @Override
+  public boolean isProtected() {
+    // otherwise this would have turned into a EmptyFieldLockInfo
+    return (remainingChecks == 0);
+  }
+
+  protected void checkFailedLockAssumption(ThreadInfo ti, ElementInfo ei, FieldInfo fi) {
+    if (remainingChecks == 0) {
+      // with no locks remaining this would have been demoted to an
+      // EmptyFieldLockInfo by now
+      lockAssumptionFailed(ti, ei, fi);
+    }
+  }
+  
+  /**
+   * this implements a path-local FieldLockInfo that are never mutated
+   * this has to be overridden for search global FieldLockInfos
+   */
+  protected FieldLockInfo getInstance (int nRemaining){
+    try {
+      ThresholdFieldLockInfo fli = (ThresholdFieldLockInfo)clone();
+      fli.remainingChecks = nRemaining;
+      return fli;
+              
+    } catch (CloneNotSupportedException cnsx){
+      throw new JPFException("clone of ThresholdFieldLockInfo failed: " + this);
+    }
+  }
+}