ApplicationServer


1   package org.openejb.spi;
2   
3   import javax.ejb.EJBHome  ;
4   import javax.ejb.EJBMetaData  ;
5   import javax.ejb.EJBObject  ;
6   import javax.ejb.Handle  ;
7   import javax.ejb.HomeHandle  ;
8   
9   import org.openejb.ProxyInfo;
10  
11  /**
12   * <h2><b>LOCAL to REMOTE SERIALIZATION</b></h2> <p>
13   * 
14   * <i>Definition:</i><p>
15   *     This is a serialization that initiates in the local vm, but
16   *     is outside the scope of a marked IntraVM local serialization.
17   * <p>
18   * <i>Circumstances:</i><p>
19   *     When an IntraVM implementation of a javax.ejb.* interface is
20   *     serialized outside the scope of the IntraVM Server
21   *     <p>
22   *     These serializations happen when objects are sent from a
23   *     local bean to a remote client as part of a return value, or
24   *     when a stateful session bean is passified.
25   * <p>
26   * <i>Action:</i><p>
27   *     Don't serialize the IntraVM javax.ejb.* interface
28   *     implementation, instead ask the ApplicationServer to nominate
29   *     its own implementation as a replacement.  This is done via
30   *     the org.openejb.spi.ApplicationServer interface.
31   * <p>
32   * <i>Example Scenario:</i><p>
33   *     SERIALIZATION<br>
34   * <br>1.  ObjectOutputStream encounters an IntraVmMetaData instance
35   *         in the object graph and calls its writeReplace method.
36   * <br>2.  The IntraVmMetaData instance determines it is being
37   *         serialized outside the scope of an IntraVM serialization
38   *         by calling IntraVmCopyMonitor.isIntraVmCopyOperation().
39   * <br>3.  The IntraVmMetaData instance calls the getEJBMetaData
40   *         method on the ApplicationServer.
41   * <br>4.  The IntraVmMetaData instance returns the
42   *         ApplicationServer's EJBMetaData instance from the
43   *         writeReplace method.
44   * <br>5.  The ObjectOutputStream serializes the ApplicationServer's
45   *         EJBMetaData instance in place of the IntraVmMetaData
46   *         instance.
47   *         <p>
48   *         Note:  The ApplicationServer's EJBMetaData instance can
49   *         be any object that implements the javax.ejb.EJBMetaData
50   *         interface and can also implement any serialization
51   *         methods, such as the writeReplace method, to nominate a
52   *         replacement or implement protocol specific logic or
53   *         otherwise gain control over the serialization of
54   *         EJBMetaData instances destined for its remote clients.
55   *         <p>
56   *     DESERIALIZATION<p>
57   *         The deserialization of the Application Server's
58   *         javax.ejb.* implementations is implementation specific.
59   * <p>        
60   * 
61   * @author <a HREF="mailto=david.blevins@visi.com">David Blevins</a>
62   * @version $Revision: 1096 $ $Date: 2004-03-26 13:41:16 -0800 (Fri, 26 Mar 2004) $
63   */
64  public interface ApplicationServer {
65      
66      public EJBMetaData   getEJBMetaData(ProxyInfo proxyInfo);
67      
68      public Handle   getHandle(ProxyInfo proxyInfo);
69         
70      public HomeHandle   getHomeHandle(ProxyInfo proxyInfo);
71         
72      public EJBObject   getEJBObject(ProxyInfo proxyInfo);
73      
74      public EJBHome   getEJBHome(ProxyInfo proxyInfo);
75      
76  }
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