| /* |
| * 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); |
| } |
| } |
| } |