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Java > Open Source Codes > org > apache > ojb > broker > core > proxy > ProxyHelper


1 package org.apache.ojb.broker.core.proxy;
2
3 /* Copyright 2002-2005 The Apache Software Foundation
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17
18 import java.lang.ref.SoftReference JavaDoc;
19 import java.lang.ref.WeakReference JavaDoc;
20 import java.lang.ref.Reference JavaDoc;
21
22 import org.apache.ojb.broker.PBFactoryException;
23
24 /**
25  * ProxyHelper used to get the real thing behind a proxy
26  *
27  * @author <a HREF="mailto:jbraeuchi@hotmail.com">Jakob Braeuchi</a>
28  * @version $Id: ProxyHelper.java,v 1.2.2.8 2005/12/21 22:25:31 tomdz Exp $
29  */
30 public class ProxyHelper
31 {
32     private static Reference JavaDoc proxyFactoryRef;
33
34     public synchronized static ProxyFactory getProxyFactory()
35     {
36         if((proxyFactoryRef == null) || (proxyFactoryRef.get() == null))
37         {
38             try
39             {
40                 /*
41                 TODO: Check usage of WeakReference
42                 arminw: Changed Soft- to WeakReference. If in AbstractProxyFactory the
43                 the ProxyFactory instance is freed this class will take care of that.
44                 */
45                 proxyFactoryRef = new WeakReference JavaDoc(AbstractProxyFactory.getProxyFactory());
46             }
47             catch(PBFactoryException ex)
48             {
49                 // seems we cannot get a broker; in that case we're defaulting to the CGLib proxy factory
50 // (which also works for older JDKs) ie. for broker-less mode (only metadata)
51 return new ProxyFactoryCGLIBImpl();
52             }
53         }
54         return (ProxyFactory) proxyFactoryRef.get();
55     }
56
57     /**
58      * Get the real Object
59      *
60      * @param objectOrProxy
61      * @return Object
62      */
63     public static final Object JavaDoc getRealObject(Object JavaDoc objectOrProxy)
64     {
65         return getProxyFactory().getRealObject(objectOrProxy);
66     }
67
68     /**
69      * Get the real Object for already materialized Handler
70      *
71      * @param objectOrProxy
72      * @return Object or null if the Handel is not materialized
73      */
74     public static final Object JavaDoc getRealObjectIfMaterialized(Object JavaDoc objectOrProxy)
75     {
76         return getProxyFactory().getRealObjectIfMaterialized(objectOrProxy);
77     }
78
79     /**
80      * Get the real Class
81      *
82      * @param objectOrProxy
83      * @return Class
84      */
85     public static final Class JavaDoc getRealClass(Object JavaDoc objectOrProxy)
86     {
87         return getProxyFactory().getRealClass(objectOrProxy);
88     }
89
90     /**
91      * Determines whether the given object is an OJB proxy.
92      *
93      * @return <code>true</code> if the object is an OJB proxy
94      */
95     public static boolean isNormalOjbProxy(Object JavaDoc proxyOrObject)
96     {
97         return getProxyFactory().isNormalOjbProxy(proxyOrObject);
98     }
99
100     /**
101      * Determines whether the given object is an OJB virtual proxy.
102      *
103      * @return <code>true</code> if the object is an OJB virtual proxy
104      */
105     public static boolean isVirtualOjbProxy(Object JavaDoc proxyOrObject)
106     {
107         return getProxyFactory().isVirtualOjbProxy(proxyOrObject);
108     }
109
110     /**
111      * Returns <tt>true</tt> if the given object is a {@link java.lang.reflect.Proxy}
112      * or a {@link VirtualProxy} instance.
113      */
114     public static boolean isProxy(Object JavaDoc proxyOrObject)
115     {
116         return getProxyFactory().isProxy(proxyOrObject);
117     }
118
119     /**
120      * Returns the invocation handler object of the given proxy object.
121      *
122      * @param obj The object
123      * @return The invocation handler if the object is an OJB proxy, or <code>null</code>
124      * otherwise
125      */
126     public static IndirectionHandler getIndirectionHandler(Object JavaDoc obj)
127     {
128         return getProxyFactory().getIndirectionHandler(obj);
129     }
130
131     /**
132      * Determines whether the object is a materialized object, i.e. no proxy or a
133      * proxy that has already been loaded from the database.
134      *
135      * @param object The object to test
136      * @return <code>true</code> if the object is materialized
137      */
138     public static boolean isMaterialized(Object JavaDoc object)
139     {
140         return getProxyFactory().isMaterialized(object);
141     }
142
143     /**
144      * Materialization-safe version of toString. If the object is a yet-unmaterialized proxy,
145      * then only the text "unmaterialized proxy for ..." is returned and the proxy is NOT
146      * materialized. Otherwise, the normal toString method is called. This useful e.g. for
147      * logging etc.
148      *
149      * @param object The object for which a string representation shall be generated
150      * @return The string representation
151      */
152     public static String JavaDoc toString(Object JavaDoc object)
153     {
154         return getProxyFactory().toString(object);
155     }
156
157     /** Return CollectionProxy for item is item is a CollectionProxy, otherwise return null */
158     public static CollectionProxy getCollectionProxy(Object JavaDoc item)
159     {
160         return getProxyFactory().getCollectionProxy(item);
161     }
162
163     /** Reports if item is a CollectionProxy. */
164     public static boolean isCollectionProxy(Object JavaDoc item)
165     {
166         // TODO: Provide handling for pluggable collection proxy implementations
167 return getProxyFactory().isCollectionProxy(item);
168     }
169 }
170
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