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     * @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}
121