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| 1 | /* | ||
| 2 | * Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package sun.tools.jstat; | ||
| 27 | |||
| 28 | import java.util.*; | ||
| 29 | import sun.jvmstat.monitor.*; | ||
| 30 | |||
| 31 | /** | ||
| 32 | * A class implementing the ExpressionEvaluator to evaluate an expression | ||
| 33 | * in the context of the available monitoring data. | ||
| 34 | * | ||
| 35 | * @author Brian Doherty | ||
| 36 | * @since 1.5 | ||
| 37 | */ | ||
| 38 | public class ExpressionExecuter implements ExpressionEvaluator { | ||
| 39 | private static final boolean debug = | ||
| 40 | Boolean.getBoolean("ExpressionEvaluator.debug"); | ||
| 41 | private MonitoredVm vm; | ||
| 42 | private HashMap<String, Object> map = new HashMap<String, Object>(); | ||
| 43 | |||
| 44 | ExpressionExecuter(MonitoredVm vm) { | ||
| 45 | this.vm = vm; | ||
| 46 | } | ||
| 47 | |||
| 48 | /* | ||
| 49 | * evaluate the given expression. | ||
| 50 | */ | ||
| 51 | public Object evaluate(Expression e) { | ||
| 52 | if (e == null) { | ||
| 53 | return null; | ||
| 54 | } | ||
| 55 | |||
| 56 | if (debug) { | ||
| 57 | System.out.println("Evaluating expression: " + e); | ||
| 58 | } | ||
| 59 | |||
| 60 | if (e instanceof Literal) { | ||
| 61 | return ((Literal)e).getValue(); | ||
| 62 | } | ||
| 63 | |||
| 64 | if (e instanceof Identifier) { | ||
| 65 | Identifier id = (Identifier)e; | ||
| 66 | if (map.containsKey(id.getName())) { | ||
| 67 | return map.get(id.getName()); | ||
| 68 | } else { | ||
| 69 | // cache the data values for coherency of the values over | ||
| 70 | // the life of this expression executer. | ||
| 71 | Monitor m = (Monitor)id.getValue(); | ||
| 72 | Object v = m.getValue(); | ||
| 73 | map.put(id.getName(), v); | ||
| 74 | return v; | ||
| 75 | } | ||
| 76 | } | ||
| 77 | |||
| 78 | Expression l = e.getLeft(); | ||
| 79 | Expression r = e.getRight(); | ||
| 80 | |||
| 81 | Operator op = e.getOperator(); | ||
| 82 | |||
| 83 | if (op == null) { | ||
| 84 | return evaluate(l); | ||
| 85 | } else { | ||
| 86 | Double lval = new Double(((Number)evaluate(l)).doubleValue()); | ||
| 87 | Double rval = new Double(((Number)evaluate(r)).doubleValue()); | ||
| 88 | double result = op.eval(lval.doubleValue(), rval.doubleValue()); | ||
| 89 | if (debug) { | ||
| 90 | System.out.println("Performed Operation: " + lval + op + rval | ||
| 91 | + " = " + result); | ||
| 92 | } | ||
| 93 | return new Double(result); | ||
| 94 | } | ||
| 95 | } | ||
| 96 | } | ||