InstanceOfQueryExp.java revision 10444:f08705540498
1/* 2 * Copyright (c) 2005, 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 26package javax.management; 27 28 29/** 30 * This class is used by the query building mechanism for isInstanceOf expressions. 31 * @serial include 32 * 33 * @since 1.6 34 */ 35class InstanceOfQueryExp extends QueryEval implements QueryExp { 36 37 /* Serial version */ 38 private static final long serialVersionUID = -1081892073854801359L; 39 40 /** 41 * @serial The {@link StringValueExp} returning the name of the class 42 * of which selected MBeans should be instances. 43 */ 44 private StringValueExp classNameValue; 45 46 /** 47 * Creates a new InstanceOfExp with a specific class name. 48 * @param classNameValue The {@link StringValueExp} returning the name of 49 * the class of which selected MBeans should be instances. 50 */ 51 // We are using StringValueExp here to be consistent with other queries, 52 // although we should actually either use a simple string (the classname) 53 // or a ValueExp - which would allow more complex queries - like for 54 // instance evaluating the class name from an AttributeValueExp. 55 // As it stands - using StringValueExp instead of a simple constant string 56 // doesn't serve any useful purpose besides offering a consistent 57 // look & feel. 58 public InstanceOfQueryExp(StringValueExp classNameValue) { 59 if (classNameValue == null) { 60 throw new IllegalArgumentException("Null class name."); 61 } 62 63 this.classNameValue = classNameValue; 64 } 65 66 /** 67 * Returns the class name. 68 * @returns The {@link StringValueExp} returning the name of 69 * the class of which selected MBeans should be instances. 70 */ 71 public StringValueExp getClassNameValue() { 72 return classNameValue; 73 } 74 75 /** 76 * Applies the InstanceOf on a MBean. 77 * 78 * @param name The name of the MBean on which the InstanceOf will be applied. 79 * 80 * @return True if the MBean specified by the name is instance of the class. 81 * @exception BadAttributeValueExpException 82 * @exception InvalidApplicationException 83 * @exception BadStringOperationException 84 * @exception BadBinaryOpValueExpException 85 */ 86 public boolean apply(ObjectName name) 87 throws BadStringOperationException, 88 BadBinaryOpValueExpException, 89 BadAttributeValueExpException, 90 InvalidApplicationException { 91 92 // Get the class name value 93 final StringValueExp val; 94 try { 95 val = (StringValueExp) classNameValue.apply(name); 96 } catch (ClassCastException x) { 97 // Should not happen - unless someone wrongly implemented 98 // StringValueExp.apply(). 99 final BadStringOperationException y = 100 new BadStringOperationException(x.toString()); 101 y.initCause(x); 102 throw y; 103 } 104 105 // Test whether the MBean is an instance of that class. 106 try { 107 return getMBeanServer().isInstanceOf(name, val.getValue()); 108 } catch (InstanceNotFoundException infe) { 109 return false; 110 } 111 } 112 113 /** 114 * Returns a string representation of this InstanceOfQueryExp. 115 * @return a string representation of this InstanceOfQueryExp. 116 */ 117 public String toString() { 118 return "InstanceOf " + classNameValue.toString(); 119 } 120} 121