Showing the changes to java/pkg/sun/tools/jstat/ExpressionExecuter.java (1 of 18352 files). Show all
Unified · Split
| @@ -0,0 +1,96 @@ | ||
| 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 | +} | |