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Java > Open Source Codes > org > jboss > axis > utils > cache > ClassCache


1 /*
2  * The Apache Software License, Version 1.1
3  *
4  * Copyright (c) 2001-2002 The Apache Software Foundation. All rights
5  * reserved.
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7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  * notice, this list of conditions and the following disclaimer.
13  *
14  * 2. Redistributions in binary form must reproduce the above copyright
15  * notice, this list of conditions and the following disclaimer in
16  * the documentation and/or other materials provided with the
17  * distribution.
18  *
19  * 3. The end-user documentation included with the redistribution,
20  * if any, must include the following acknowledgment:
21  * "This product includes software developed by the
22  * Apache Software Foundation (http://www.apache.org/)."
23  * Alternately, this acknowledgment may appear in the software itself,
24  * if and wherever such third-party acknowledgments normally appear.
25  *
26  * 4. The names "Axis" and "Apache Software Foundation" must
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28  * software without prior written permission. For written
29  * permission, please contact apache@apache.org.
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31  * 5. Products derived from this software may not be called "Apache",
32  * nor may "Apache" appear in their name, without prior written
33  * permission of the Apache Software Foundation.
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35  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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41  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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43  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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45  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46  * SUCH DAMAGE.
47  * ====================================================================
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49  * This software consists of voluntary contributions made by many
50  * individuals on behalf of the Apache Software Foundation. For more
51  * information on the Apache Software Foundation, please see
52  * <http://www.apache.org/>.
53  */
54
55 package org.jboss.axis.utils.cache;
56
57 import org.jboss.axis.utils.ClassUtils;
58
59 import java.util.Hashtable JavaDoc;
60
61 /**
62  * A cache class for JavaClass objects, which enables us to quickly reference
63  * methods.
64  *
65  * @author Doug Davis (dug@us.ibm.com)
66  * @author Glen Daniels (gdaniels@apache.org)
67  */
68 public class ClassCache
69 {
70    Hashtable JavaDoc classCache = new Hashtable JavaDoc();
71
72    public ClassCache()
73    {
74    }
75
76    /**
77     * Register a class in the cache. Creates a new JavaClass object
78     * around the given class, and inserts it into the Hashtable, replacing
79     * any previous entry.
80     *
81     * @param name the name of the class.
82     * @param cls a Java Class.
83     */
84    public synchronized void registerClass(String JavaDoc name, Class JavaDoc cls)
85    {
86       if (name == null) return; // ??? Should we let this NPE?
87 JavaClass oldClass = (JavaClass)classCache.get(name);
88       if (oldClass != null && oldClass.getJavaClass() == cls) return;
89       classCache.put(name, new JavaClass(cls));
90    }
91
92    /**
93     * Remove an entry from the cache.
94     *
95     * @param name the name of the class to remove.
96     */
97    public synchronized void deregisterClass(String JavaDoc name)
98    {
99       classCache.remove(name);
100    }
101
102    /**
103     * Query a given class' cache status.
104     *
105     * @param name a class name
106     * @return true if the class is in the cache, false otherwise
107     */
108    public boolean isClassRegistered(String JavaDoc name)
109    {
110       return (classCache != null && classCache.get(name) != null);
111    }
112
113    /**
114     * Find the cached JavaClass entry for this class, creating one
115     * if necessary.
116     *
117     * @param className name of the class desired
118     * @param cl ClassLoader to use if we need to load the class
119     * @return JavaClass entry
120     */
121    public JavaClass lookup(String JavaDoc className, ClassLoader JavaDoc cl)
122            throws ClassNotFoundException JavaDoc
123    {
124       if (className == null)
125       {
126          return null;
127       }
128       JavaClass jc = (JavaClass)classCache.get(className);
129       if ((jc == null) && (cl != null))
130       {
131          // Try to load the class with the specified classloader
132 Class JavaDoc cls = ClassUtils.forName(className, true, cl);
133          jc = new JavaClass(cls);
134       }
135       return jc;
136    }
137 }
138
139 ;
140
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