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Java > Open Source Codes > org > jboss > invocation > InvokerInterceptor


1 /*
2 * JBoss, Home of Professional Open Source
3 * Copyright 2005, JBoss Inc., and individual contributors as indicated
4 * by the @authors tag. See the copyright.txt in the distribution for a
5 * full listing of individual contributors.
6 *
7 * This is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU Lesser General Public License as
9 * published by the Free Software Foundation; either version 2.1 of
10 * the License, or (at your option) any later version.
11 *
12 * This software is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this software; if not, write to the Free
19 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
21 */
22 package org.jboss.invocation;
23
24 import java.io.Externalizable JavaDoc;
25 import java.io.IOException JavaDoc;
26 import java.io.ObjectInput JavaDoc;
27 import java.io.ObjectOutput JavaDoc;
28 import java.lang.reflect.UndeclaredThrowableException JavaDoc;
29
30 import javax.transaction.Transaction JavaDoc;
31
32 import org.jboss.invocation.Invocation;
33 import org.jboss.invocation.Invoker;
34
35 import org.jboss.proxy.Interceptor;
36
37 import org.jboss.system.Registry;
38 import org.jboss.util.id.GUID;
39
40 /**
41  * A very simple implementation of it that branches to the local stuff.
42  *
43  * @author <a HREF="mailto:marc.fleury@jboss.org">Marc Fleury</a>
44  * @author Scott.Stark@jboss.org
45  * @version $Revision: 37459 $
46  */
47 public class InvokerInterceptor
48    extends Interceptor
49    implements Externalizable JavaDoc
50 {
51    /** Serial Version Identifier. @since 1.2 */
52    private static final long serialVersionUID = 2548120545997920357L;
53
54    /** The value of our local Invoker.ID to detect when we are local. */
55    private GUID invokerID = Invoker.ID;
56
57    /** Invoker to the remote JMX node. */
58    protected Invoker remoteInvoker;
59
60    /** Static references to local invokers. */
61    protected static Invoker localInvoker;
62
63    /** The InvokerProxyHA class */
64    protected static Class JavaDoc invokerProxyHA;
65    
66    static
67    {
68       try
69       {
70          // Using Class.forName() to avoid security problems in the client
71 invokerProxyHA = Class.forName("org.jboss.invocation.InvokerProxyHA");
72       }
73       catch (Throwable JavaDoc ignored)
74       {
75       }
76    }
77    
78    /**
79     * Get the local invoker reference, useful for optimization.
80     */
81    public static Invoker getLocal()
82    {
83       return localInvoker;
84    }
85
86    /**
87     * Set the local invoker reference, useful for optimization.
88     */
89    public static void setLocal(Invoker invoker)
90    {
91       localInvoker = invoker;
92    }
93
94    /**
95     * Exposed for externalization.
96     */
97    public InvokerInterceptor()
98    {
99       super();
100    }
101
102    /**
103     * Returns wether we are local to the originating container or not.
104     *
105     * @return true when we have the same GUID
106     */
107    public boolean isLocal()
108    {
109       return invokerID.equals(Invoker.ID);
110    }
111
112    /**
113     * Whether the target is local
114     *
115     * @param invocation the invocation
116     * @return true when the target is local
117     */
118    public boolean isLocal(Invocation invocation)
119    {
120       // No local invoker, it must be remote
121 if (localInvoker == null)
122          return false;
123
124       // The proxy was downloaded from a remote location
125 if (isLocal() == false)
126       {
127          // It is not clustered so we go remote
128 if (isClustered(invocation) == false)
129             return false;
130       }
131       
132       // See whether we have a local target
133 return hasLocalTarget(invocation);
134    }
135    
136    /**
137     * Whether we are in a clustered environment<p>
138     *
139     * NOTE: This should be future compatible under any
140     * new design where a prior target chooser interceptor
141     * picks a non HA target than that code being
142     * inside a ha invoker.
143     *
144     * @param invocation the invocation
145     * @return true when a clustered invoker
146     */
147    public boolean isClustered(Invocation invocation)
148    {
149       // No clustering classes
150 if (invokerProxyHA == null)
151          return false;
152       
153       // Is the invoker a HA invoker?
154 InvocationContext ctx = invocation.getInvocationContext();
155       Invoker invoker = ctx.getInvoker();
156       return invoker != null && invokerProxyHA.isAssignableFrom(invoker.getClass());
157    }
158    
159    /**
160     * Whether there is a local target
161     *
162     * @param invocation
163     * @return true when in the registry
164     */
165    public boolean hasLocalTarget(Invocation invocation)
166    {
167       return Registry.lookup(invocation.getObjectName()) != null;
168    }
169    
170    /**
171     * The invocation on the delegate, calls the right invoker.
172     * Remote if we are remote, local if we are local.
173     */
174    public Object JavaDoc invoke(Invocation invocation)
175       throws Exception JavaDoc
176    {
177       // optimize if calling another bean in same server VM
178 if (isLocal(invocation))
179          return invokeLocal(invocation);
180       else
181          return invokeInvoker(invocation);
182    }
183
184    /**
185     * Invoke using local invoker
186     *
187     * @param invocation the invocation
188     * @return the result
189     * @throws Exception for any error
190     */
191    protected Object JavaDoc invokeLocal(Invocation invocation) throws Exception JavaDoc
192    {
193       return localInvoker.invoke(invocation);
194    }
195
196    /**
197     * Invoke using local invoker and marshalled
198     *
199     * @param invocation the invocation
200     * @return the result
201     * @throws Exception for any error
202     */
203    protected Object JavaDoc invokeMarshalled(Invocation invocation) throws Exception JavaDoc
204    {
205       MarshalledInvocation mi = new MarshalledInvocation(invocation);
206       MarshalledValue copy = new MarshalledValue(mi);
207       Invocation invocationCopy = (Invocation) copy.get();
208
209       // copy the Tx
210 Transaction JavaDoc tx = invocation.getTransaction();
211       invocationCopy.setTransaction(tx);
212
213       try
214       {
215          Object JavaDoc rtnValue = localInvoker.invoke(invocationCopy);
216          MarshalledValue mv = new MarshalledValue(rtnValue);
217          return mv.get();
218       }
219       catch(Throwable JavaDoc t)
220       {
221          MarshalledValue mv = new MarshalledValue(t);
222          Throwable JavaDoc t2 = (Throwable JavaDoc) mv.get();
223          if( t2 instanceof Exception JavaDoc )
224             throw (Exception JavaDoc) t2;
225          else
226             throw new UndeclaredThrowableException JavaDoc(t2);
227       }
228    }
229
230    /**
231     * Invoke using invoker
232     *
233     * @param invocation the invocation
234     * @return the result
235     * @throws Exception for any error
236     */
237    protected Object JavaDoc invokeInvoker(Invocation invocation) throws Exception JavaDoc
238    {
239       InvocationContext ctx = invocation.getInvocationContext();
240       Invoker invoker = ctx.getInvoker();
241       return invoker.invoke(invocation);
242    }
243    
244    /**
245     * Externalize this instance.
246     *
247     * <p>
248     * If this instance lives in a different VM than its container
249     * invoker, the remote interface of the container invoker is
250     * not externalized.
251     */
252    public void writeExternal(final ObjectOutput JavaDoc out)
253       throws IOException JavaDoc
254    {
255       out.writeObject(invokerID);
256    }
257
258    /**
259     * Un-externalize this instance.
260     *
261     * <p>
262     * We check timestamps of the interfaces to see if the instance is in the original
263     * VM of creation
264     */
265    public void readExternal(final ObjectInput JavaDoc in)
266       throws IOException JavaDoc, ClassNotFoundException JavaDoc
267    {
268       invokerID = (GUID)in.readObject();
269    }
270 }
271
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