J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2004 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.tools.jstat; |
| 27 | |
| 28 | import sun.jvmstat.monitor.*; |
| 29 | import sun.management.counter.Variability; |
| 30 | |
| 31 | /** |
| 32 | * A class implementing the ExpressionEvaluator to resolve unresolved |
| 33 | * symbols in an Expression in the context of the available monitoring data. |
| 34 | * This class also performs some minimal optimizations of the expressions, |
| 35 | * such as simplification of constant subexpressions. |
| 36 | * |
| 37 | * @author Brian Doherty |
| 38 | * @since 1.5 |
| 39 | */ |
| 40 | public class ExpressionResolver implements ExpressionEvaluator { |
| 41 | private static boolean debug = Boolean.getBoolean("ExpressionResolver.debug"); |
| 42 | private MonitoredVm vm; |
| 43 | |
| 44 | ExpressionResolver(MonitoredVm vm) { |
| 45 | this.vm = vm; |
| 46 | } |
| 47 | |
| 48 | /* |
| 49 | * evaluate the given expression. evaluation in this case means |
| 50 | * to resolve the counter names in the expression |
| 51 | */ |
| 52 | public Object evaluate(Expression e) throws MonitorException { |
| 53 | |
| 54 | if (e == null) { |
| 55 | return null; |
| 56 | } |
| 57 | |
| 58 | if (debug) { |
| 59 | System.out.println("Resolving Expression:" + e); |
| 60 | } |
| 61 | |
| 62 | if (e instanceof Identifier) { |
| 63 | Identifier id = (Identifier)e; |
| 64 | |
| 65 | // check if it's already resolved |
| 66 | if (id.isResolved()) { |
| 67 | return id; |
| 68 | } |
| 69 | |
| 70 | // look it up |
| 71 | Monitor m = vm.findByName(id.getName()); |
| 72 | if (m == null) { |
| 73 | System.err.println("Warning: Unresolved Symbol: " |
| 74 | + id.getName() + " substituted NaN"); |
| 75 | return new Literal(new Double(Double.NaN)); |
| 76 | } |
| 77 | if (m.getVariability() == Variability.CONSTANT) { |
| 78 | if (debug) { |
| 79 | System.out.println("Converting constant " + id.getName() |
| 80 | + " to literal with value " |
| 81 | + m.getValue()); |
| 82 | } |
| 83 | return new Literal(m.getValue()); |
| 84 | } |
| 85 | id.setValue(m); |
| 86 | return id; |
| 87 | } |
| 88 | |
| 89 | if (e instanceof Literal) { |
| 90 | return e; |
| 91 | } |
| 92 | |
| 93 | Expression l = null; |
| 94 | Expression r = null; |
| 95 | |
| 96 | if (e.getLeft() != null) { |
| 97 | l = (Expression)evaluate(e.getLeft()); |
| 98 | } |
| 99 | if (e.getRight() != null) { |
| 100 | r = (Expression)evaluate(e.getRight()); |
| 101 | } |
| 102 | |
| 103 | if (l != null && r != null) { |
| 104 | if ((l instanceof Literal) && (r instanceof Literal)) { |
| 105 | Literal ll = (Literal)l; |
| 106 | Literal rl = (Literal)r; |
| 107 | boolean warn = false; |
| 108 | |
| 109 | Double nan = new Double(Double.NaN); |
| 110 | if (ll.getValue() instanceof String) { |
| 111 | warn = true; ll.setValue(nan); |
| 112 | } |
| 113 | if (rl.getValue() instanceof String) { |
| 114 | warn = true; rl.setValue(nan); |
| 115 | } |
| 116 | if (debug && warn) { |
| 117 | System.out.println("Warning: String literal in " |
| 118 | + "numerical expression: " |
| 119 | + "substitutied NaN"); |
| 120 | } |
| 121 | |
| 122 | // perform the operation |
| 123 | Number ln = (Number)ll.getValue(); |
| 124 | Number rn = (Number)rl.getValue(); |
| 125 | double result = e.getOperator().eval(ln.doubleValue(), |
| 126 | rn.doubleValue()); |
| 127 | if (debug) { |
| 128 | System.out.println("Converting expression " + e |
| 129 | + " (left = " + ln.doubleValue() + ")" |
| 130 | + " (right = " + rn.doubleValue() + ")" |
| 131 | + " to literal value " + result); |
| 132 | } |
| 133 | return new Literal(new Double(result)); |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | if (l != null && r == null) { |
| 138 | return l; |
| 139 | } |
| 140 | |
| 141 | e.setLeft(l); |
| 142 | e.setRight(r); |
| 143 | |
| 144 | return e; |
| 145 | } |
| 146 | } |