OpBean


1   /**
2    * JOnAS: Java(TM) Open Application Server
3    * Copyright (C) 1999-2004 Bull S.A.
4    * Contact: jonas-team@objectweb.org
5    *
6    * This library is free software; you can redistribute it and/or
7    * modify it under the terms of the GNU Lesser General Public
8    * License as published by the Free Software Foundation; either
9    * version 2.1 of the License, or any later version.
10   *
11   * This library is distributed in the hope that it will be useful,
12   * but WITHOUT ANY WARRANTY; without even the implied warranty of
13   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14   * Lesser General Public License for more details.
15   *
16   * You should have received a copy of the GNU Lesser General Public
17   * License along with this library; if not, write to the Free Software
18   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
19   * USA
20   *
21   * Initial developer(s):
22   * --------------------------------------------------------------------------
23   * $Id: OpBean.java,v 1.2 2004/04/13 14:11:22 benoitf Exp $
24   * --------------------------------------------------------------------------
25   */
26  
27  package org.objectweb.earsample.beans.secusb;
28  
29  import javax.ejb.EJBException  ;
30  import javax.ejb.SessionBean  ;
31  import javax.ejb.SessionContext  ;
32  import javax.ejb.SessionSynchronization  ;
33  
34  /**
35   * This is an example of Session Bean, statefull, and synchronized.
36   * @author JOnAS team
37   */
38  public class OpBean implements SessionBean  , SessionSynchronization   {
39  
40      /**
41       * Actual state of the bean
42       */
43      private int total = 0;
44  
45      /**
46       * value inside Tx, not yet committed.
47       */
48      private int newtotal = 0;
49  
50      /**
51       * User client
52       */
53      private String   clientUser = null;
54  
55      /**
56       * Session context that the container provides for a session enterprise Bean
57       * instance.
58       */
59      private SessionContext   sessionContext = null;
60  
61      /* ========================= ejbCreate methods ============================ */
62  
63      /**
64       * There must be one ejbCreate() method per create() method on the Home
65       * interface, and with the same signature.
66       * @param user the user name
67       */
68      public void ejbCreate(String   user) {
69          total = 0;
70          // in case we are outside transactions
71          newtotal = total;
72          clientUser = user;
73      }
74  
75      /* =============== javax.ejb.SessionBean 2.0 implementation ============== */
76  
77      /**
78       * The activate method is called when the instance is activated from its
79       * "passive" state. The instance should acquire any resource that it has
80       * released earlier in the ejbPassivate() method. This method is called with
81       * no transaction context.
82       * @throws EJBException Thrown by the method to indicate a failure caused by
83       *         a system-level error.
84       * @throws java.rmi.RemoteException This exception is defined in the method
85       *         signature to provide backward compatibility for enterprise beans
86       *         written for the EJB 1.0 specification. Enterprise beans written
87       *         for the EJB 1.1 specification should throw the
88       *         javax.ejb.EJBException instead of this exception. Enterprise
89       *         beans written for the EJB2.0 and higher specifications must throw
90       *         the javax.ejb.EJBException instead of this exception.
91       */
92      public void ejbActivate() throws EJBException  , java.rmi.RemoteException   {
93          // Nothing to do for this simple example
94      }
95  
96      /**
97       * The passivate method is called before the instance enters the "passive"
98       * state. The instance should release any resources that it can re-acquire
99       * later in the ejbActivate() method. After the passivate method completes,
100      * the instance must be in a state that allows the container to use the Java
101      * Serialization protocol to externalize and store away the instance's
102      * state. This method is called with no transaction context.
103      * @throws EJBException Thrown by the method to indicate a failure caused by
104      *         a system-level error.
105      * @throws java.rmi.RemoteException This exception is defined in the method
106      *         signature to provide backward compatibility for enterprise beans
107      *         written for the EJB 1.0 specification. Enterprise beans written
108      *         for the EJB 1.1 specification should throw the
109      *         javax.ejb.EJBException instead of this exception. Enterprise
110      *         beans written for the EJB2.0 and higher specifications must throw
111      *         the javax.ejb.EJBException instead of this exception.
112      */
113     public void ejbPassivate() throws EJBException  , java.rmi.RemoteException   {
114         // Nothing to do for this simple example
115     }
116 
117     /**
118      * A container invokes this method before it ends the life of the session
119      * object. This happens as a result of a client's invoking a remove
120      * operation, or when a container decides to terminate the session object
121      * after a timeout. This method is called with no transaction context.
122      * @throws EJBException Thrown by the method to indicate a failure caused by
123      *         a system-level error.
124      * @throws java.rmi.RemoteException This exception is defined in the method
125      *         signature to provide backward compatibility for enterprise beans
126      *         written for the EJB 1.0 specification. Enterprise beans written
127      *         for the EJB 1.1 specification should throw the
128      *         javax.ejb.EJBException instead of this exception. Enterprise
129      *         beans written for the EJB2.0 and higher specifications must throw
130      *         the javax.ejb.EJBException instead of this exception.
131      */
132     public void ejbRemove() throws EJBException  , java.rmi.RemoteException   {
133         // Nothing to do for this simple example
134     }
135 
136     /**
137      * Set the associated session context. The container calls this method after
138      * the instance creation. The enterprise Bean instance should store the
139      * reference to the context object in an instance variable. This method is
140      * called with no transaction context.
141      * @param sessionContext A SessionContext interface for the instance.
142      * @throws EJBException Thrown by the method to indicate a failure caused by
143      *         a system-level error.
144      * @throws java.rmi.RemoteException This exception is defined in the method
145      *         signature to provide backward compatibility for applications
146      *         written for the EJB 1.0 specification. Enterprise beans written
147      *         for the EJB 1.1 specification should throw the
148      *         javax.ejb.EJBException instead of this exception. Enterprise
149      *         beans written for the EJB2.0 and higher specifications must throw
150      *         the javax.ejb.EJBException instead of this exception.
151      */
152     public void setSessionContext(SessionContext   sessionContext) throws EJBException  , java.rmi.RemoteException   {
153         this.sessionContext = sessionContext;
154     }
155 
156     /*
157      * ============== javax.ejb.SessionSynchronization implementation
158      * =============
159      */
160 
161     /**
162      * The afterBegin method notifies a session Bean instance that a new
163      * transaction has started, and that the subsequent business methods on the
164      * instance will be invoked in the context of the transaction. The instance
165      * can use this method, for example, to read data from a database and cache
166      * the data in the instance fields. This method executes in the proper
167      * transaction context.
168      * @throws EJBException Thrown by the method to indicate a failure caused by
169      *         a system-level error.
170      * @throws java.rmi.RemoteException - This exception is defined in the
171      *         method signature to provide backward compatibility for enterprise
172      *         beans written for the EJB 1.0 specification. Enterprise beans
173      *         written for the EJB 1.1 and higher specifications should throw
174      *         the javax.ejb.EJBException instead of this exception. Enterprise
175      *         beans written for the EJB 2.0 and higher specifications must not
176      *         throw the java.rmi.RemoteException.
177      */
178     public void afterBegin() throws EJBException  , java.rmi.RemoteException   {
179         newtotal = total;
180     }
181 
182     /**
183      * The beforeCompletion method notifies a session Bean instance that a
184      * transaction is about to be committed. The instance can use this method,
185      * for example, to write any cached data to a database. This method executes
186      * in the proper transaction context. <b>Note: </b> The instance may still
187      * cause the container to rollback the transaction by invoking the
188      * setRollbackOnly() method on the instance context, or by throwing an
189      * exception.
190      * @throws EJBException Thrown by the method to indicate a failure caused by
191      *         a system-level error.
192      * @throws java.rmi.RemoteException - This exception is defined in the
193      *         method signature to provide backward compatibility for enterprise
194      *         beans written for the EJB 1.0 specification. Enterprise beans
195      *         written for the EJB 1.1 and higher specifications should throw
196      *         the javax.ejb.EJBException instead of this exception. Enterprise
197      *         beans written for the EJB 2.0 and higher specifications must not
198      *         throw the java.rmi.RemoteException.
199      */
200     public void beforeCompletion() throws EJBException  , java.rmi.RemoteException   {
201     }
202 
203     /**
204      * The afterCompletion method notifies a session Bean instance that a
205      * transaction commit protocol has completed, and tells the instance whether
206      * the transaction has been committed or rolled back. This method executes
207      * with no transaction context.
208      * @param committed - True if the transaction has been committed, false if
209      *        is has been rolled back.
210      * @throws EJBException Thrown by the method to indicate a failure caused by
211      *         a system-level error.
212      * @throws java.rmi.RemoteException - This exception is defined in the
213      *         method signature to provide backward compatibility for enterprise
214      *         beans written for the EJB 1.0 specification. Enterprise beans
215      *         written for the EJB 1.1 and higher specifications should throw
216      *         the javax.ejb.EJBException instead of this exception. Enterprise
217      *         beans written for the EJB 2.0 and higher specifications must not
218      *         throw the java.rmi.RemoteException.
219      */
220     public void afterCompletion(boolean committed) throws EJBException  , java.rmi.RemoteException   {
221 
222         if (committed) {
223             total = newtotal;
224         } else {
225             newtotal = total;
226         }
227     }
228 
229     /* ========================= Op implementation ============================ */
230 
231     /**
232      * Business method implementation.
233      * @param s nb of shares to be bought
234      */
235     public void buy(int s) {
236         newtotal = newtotal + s;
237         return;
238     }
239 
240     /**
241      * Business method implementation.
242      * @return the nb of shares bought
243      */
244     public int read() {
245         return newtotal;
246     }
247 }
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