0N/A/*
2362N/A * Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
0N/A * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
0N/A *
0N/A * This code is free software; you can redistribute it and/or modify it
0N/A * under the terms of the GNU General Public License version 2 only, as
2362N/A * published by the Free Software Foundation. Oracle designates this
0N/A * particular file as subject to the "Classpath" exception as provided
2362N/A * by Oracle in the LICENSE file that accompanied this code.
0N/A *
0N/A * This code is distributed in the hope that it will be useful, but WITHOUT
0N/A * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
0N/A * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
0N/A * version 2 for more details (a copy is included in the LICENSE file that
0N/A * accompanied this code).
0N/A *
0N/A * You should have received a copy of the GNU General Public License version
0N/A * 2 along with this work; if not, write to the Free Software Foundation,
0N/A * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
0N/A *
2362N/A * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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0N/A */
0N/A
0N/Apackage sun.tools.jstat;
0N/A
0N/Aimport java.util.*;
0N/Aimport sun.jvmstat.monitor.*;
0N/A
0N/A/**
0N/A * A class implementing the ExpressionEvaluator to evaluate an expression
0N/A * in the context of the available monitoring data.
0N/A *
0N/A * @author Brian Doherty
0N/A * @since 1.5
0N/A */
0N/Apublic class ExpressionExecuter implements ExpressionEvaluator {
0N/A private static final boolean debug =
0N/A Boolean.getBoolean("ExpressionEvaluator.debug");
0N/A private MonitoredVm vm;
0N/A private HashMap<String, Object> map = new HashMap<String, Object>();
0N/A
0N/A ExpressionExecuter(MonitoredVm vm) {
0N/A this.vm = vm;
0N/A }
0N/A
0N/A /*
0N/A * evaluate the given expression.
0N/A */
0N/A public Object evaluate(Expression e) {
0N/A if (e == null) {
0N/A return null;
0N/A }
0N/A
0N/A if (debug) {
0N/A System.out.println("Evaluating expression: " + e);
0N/A }
0N/A
0N/A if (e instanceof Literal) {
0N/A return ((Literal)e).getValue();
0N/A }
0N/A
0N/A if (e instanceof Identifier) {
0N/A Identifier id = (Identifier)e;
0N/A if (map.containsKey(id.getName())) {
0N/A return map.get(id.getName());
0N/A } else {
0N/A // cache the data values for coherency of the values over
0N/A // the life of this expression executer.
0N/A Monitor m = (Monitor)id.getValue();
0N/A Object v = m.getValue();
0N/A map.put(id.getName(), v);
0N/A return v;
0N/A }
0N/A }
0N/A
0N/A Expression l = e.getLeft();
0N/A Expression r = e.getRight();
0N/A
0N/A Operator op = e.getOperator();
0N/A
0N/A if (op == null) {
0N/A return evaluate(l);
0N/A } else {
0N/A Double lval = new Double(((Number)evaluate(l)).doubleValue());
0N/A Double rval = new Double(((Number)evaluate(r)).doubleValue());
0N/A double result = op.eval(lval.doubleValue(), rval.doubleValue());
0N/A if (debug) {
0N/A System.out.println("Performed Operation: " + lval + op + rval
0N/A + " = " + result);
0N/A }
0N/A return new Double(result);
0N/A }
0N/A }
0N/A}