Initial

git-svn-id: https://wala.svn.sourceforge.net/svnroot/wala/trunk@1059 f5eafffb-2e1d-0410-98e4-8ec43c5233c4

com.ibm.wala.core/src/com/ibm/wala/logic/NullConstant.java

@@ -0,0 +1,39 @@
+/*******************************************************************************
+ * Copyright (c) 2006 IBM Corporation.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package com.ibm.wala.logic;
+
+/**
+ * @author schandra_sf
+ */
+
+import java.util.Collection;
+import java.util.Collections;
+
+public class NullConstant implements IConstant {
+	
+	static NullConstant SINGLE = new NullConstant();
+	
+	public static NullConstant make() {
+		return SINGLE;
+	}
+
+	public Collection<Variable> getFreeVariables() {
+		return Collections.emptySet();
+	}
+
+	public Kind getKind() {
+		return Kind.CONSTANT;
+	}
+
+	public String toString() {
+		return "null";
+	}
+}