--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/jdk.jcmd/share/classes/sun/tools/jstat/ExpressionExecuter.java	Sun Aug 17 15:54:13 2014 +0100
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package sun.tools.jstat;
+
+import java.util.*;
+import sun.jvmstat.monitor.*;
+
+/**
+ * A class implementing the ExpressionEvaluator to evaluate an expression
+ * in the context of the available monitoring data.
+ *
+ * @author Brian Doherty
+ * @since 1.5
+ */
+public class ExpressionExecuter implements ExpressionEvaluator {
+    private static final boolean debug =
+            Boolean.getBoolean("ExpressionEvaluator.debug");
+    private MonitoredVm vm;
+    private HashMap<String, Object> map = new HashMap<String, Object>();
+
+    ExpressionExecuter(MonitoredVm vm) {
+        this.vm = vm;
+    }
+
+    /*
+     * evaluate the given expression.
+     */
+    public Object evaluate(Expression e) {
+        if (e == null) {
+            return null;
+        }
+
+        if (debug) {
+            System.out.println("Evaluating expression: " + e);
+        }
+
+        if (e instanceof Literal) {
+            return ((Literal)e).getValue();
+        }
+
+        if (e instanceof Identifier) {
+            Identifier id = (Identifier)e;
+            if (map.containsKey(id.getName())) {
+                return map.get(id.getName());
+            } else {
+                // cache the data values for coherency of the values over
+                // the life of this expression executer.
+                Monitor m = (Monitor)id.getValue();
+                Object v = m.getValue();
+                map.put(id.getName(), v);
+                return v;
+            }
+        }
+
+        Expression l = e.getLeft();
+        Expression r = e.getRight();
+
+        Operator op = e.getOperator();
+
+        if (op == null) {
+            return evaluate(l);
+        } else {
+            Double lval = new Double(((Number)evaluate(l)).doubleValue());
+            Double rval = new Double(((Number)evaluate(r)).doubleValue());
+            double result = op.eval(lval.doubleValue(), rval.doubleValue());
+            if (debug) {
+                System.out.println("Performed Operation: " + lval + op + rval
+                                   + " = " + result);
+            }
+            return new Double(result);
+        }
+    }
+}