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 
  26 package 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  */
  35 class 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      * @return 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 }