< prev index next >

src/java.corba/share/classes/org/omg/PortableServer/package.html

Print this page


   1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
   2 <html>
   3 <head>
   4 <!--
   5  
   6  Copyright (c) 2000, 2006, Oracle and/or its affiliates. All rights reserved.
   7  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   8 
   9  This code is free software; you can redistribute it and/or modify it
  10  under the terms of the GNU General Public License version 2 only, as
  11  published by the Free Software Foundation.  Oracle designates this
  12  particular file as subject to the "Classpath" exception as provided
  13  by Oracle in the LICENSE file that accompanied this code.
  14 
  15  This code is distributed in the hope that it will be useful, but WITHOUT
  16  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  17  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  18  version 2 for more details (a copy is included in the LICENSE file that
  19  accompanied this code).
  20 
  21  You should have received a copy of the GNU General Public License version
  22  2 along with this work; if not, write to the Free Software Foundation,
  23  Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  24 
  25  Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  26  or visit www.oracle.com if you need additional information or have any


  35 portable across multivendor ORBs.
  36 
  37 <P>In Java, Portable Object Adaptor (POA)-based Dynamic Skeleton Interface (DSI) 
  38 servants inherit from the  standard <TT>DynamicImplementation</TT> class, which 
  39 inherits from the <TT>Servant</TT> class. The native <TT>Servant</TT> type is 
  40 defined by the <TT>PortableServer</TT> module for the POA. In Java, the 
  41   <TT>Servant</TT> type is mapped to the Java 
  42   <TT>org.omg.PortableServer.Servant</TT> class.
  43   It serves as the base class for all POA servant 
  44   implementations and provides a number of methods that may 
  45   be invoked by the application programmer, as well as methods 
  46   which are invoked by the POA itself and may be overridden by 
  47   the user to control aspects of servant behavior. 
  48   
  49 <H2>Package Specification</H2>
  50  
  51 <P>For a precise list of supported sections of official OMG specifications with which 
  52 the Java[tm] Platform, Standard Edition 6 complies, see <A 
  53 HREF="../CORBA/doc-files/compliance.html">Official Specifications for CORBA 
  54 support in Java[tm] SE 6</A>.
  55 <p>
  56 
  57 <H2>POA-related Interfaces</H2>
  58 
  59 <P>The <TT>PortableServer</TT> module defines the following POA-related interfaces:
  60 <P>
  61 <UL>
  62         <LI><TT>POA</TT>
  63         <LI><TT>POAManager</TT>
  64         <LI><TT>ServantManager</TT>
  65         <LI><TT>ServantActivator</TT>
  66         <LI><TT>ServantLocator</TT>
  67         <LI><TT>AdapterActivator</TT>
  68         <LI><TT>ThreadPolicy</TT>
  69         <LI><TT>LifespanPolicy</TT>
  70         <LI><TT>IdUniquenessPolicy</TT>
  71         <LI><TT>IdAssignmentPolicy</TT>
  72         <LI><TT>ImplicitActivationPolicy</TT>
  73         <LI><TT>ServantRetentionPolicy</TT>
  74         <LI><TT>RequestProcessingPolicy</TT>
  75         <LI><TT>Current</TT>
  76 </UL>
  77 
  78 <P>In addition, the POA defines the <TT>Servant</TT> native type.
  79 
  80 <H3>Operations classes</H3>
  81 
  82 <P>Each of the interfaces listed above has an associated <code>Operations</code> interface.  The <code>Operations</code> interface is generated by the <code>idlj</code> compiler and contains the method signatures for methods defined in its associated interface.  The <code>Operations</code> interface can be accessed by both the client and the server, while its associated interface can only be called by the client.




  83 
  84 <H3>Value Classes</H3>
  85 
  86 Classes ending in the suffix <code>PolicyValue</code> provide the values used for the <code>create_POA</code> call, which sets the policy for the POA.   See the <a href="#sampleserver">sample code</a> below for a demonstration.  <code>PolicyValue</code> files include the following:
  87 <P>


  88 <UL>
  89 <LI><code>IdAssignmentPolicyValue</code> 
  90 <LI><code>IdUniquenessPolicyValue</code>
  91 <LI><code>ImplicitActivationPolicyValue</code>
  92 <LI><code>LifespanPolicyValue</code>
  93 <LI><code>RequestProcessingPolicyValue</code>
  94 <LI><code>ServantRetentionPolicyValue</code>
  95 <LI><code>ThreadPolicyValue</code>
  96 </UL>
  97 
  98 <H3>Helper Classes</H3>
  99 
 100 <P>Helper classes, which are generated for all user-defined types in an OMG IDL 
 101 interface, supply static methods needed to manipulate those types.  There is only one method in a helper class that an application programmer uses: the  <code>narrow</code> method.  Only Java interfaces mapped from IDL interfaces will have a helper class that includes a <code>narrow</code> method, so in the <code>PortableServer</code> package, only the following classes have a <code>narrow</code> method:
 102 <P>



 103 <UL>
 104 <LI><code>ForwardRequestHelper</code>
 105 <LI><code>ServantActivatorHelper</code>
 106 <LI><code>ServantLocatorHelper</code>
 107 </UL>
 108 
 109 <H3>POA Classes</H3>
 110 
 111 <P>POA classes are used to implement the <code>ServantActivator</code> or <code>ServantLocator</code>.
 112 
 113 <H3>Exceptions</H3>
 114 
 115 <P>The <code>ForwardRequest</code> exception indicates to the ORB 
 116 that it is responsible for delivering the current request and subsequent <code>ForwardRequest</code> requests to the object denoted in the 
 117  <code>forward_reference</code> member of the exception.

 118 
 119 <H3>Interfaces Implemented by the Application Programmer</H3>
 120 
 121 <P>Most of what <code>PortableServer</code> does is transparent to the user.  The result is that programmers will use only a few of the interfaces mentioned above.  The remaining interfaces will be provided by the ORB implementation.  The interfaces of interest to application programmers are the following:
 122 <P>


 123 <ul>
 124         <LI><code>AdapterActivator</code>
 125         <P>Adapter activators are associated with POAs.  An adapter activator supplies a POA with the ability to create child POAs on demand, as a side-effect of receiving a request that names the child POA (or one of its children), or when <code>find_POA</code> is called with an activate parameter value of <code>TRUE</code>.  An application server that creates all its needed POAs at the beginning of execution does not need to use or provide an adapter activator; it is necessary only for the case in which POAs need to be created during request processing.
 126         <P>





 127         <LI><code>ServantLocator</code>
 128         <P>When the POA has the <code>NON_RETAIN</code> policy, it uses servant managers that are <code>ServantLocator</code>s.
 129         <P>
 130         <LI><code>ServantActivator</code>
 131         <P>When the POA has the <code>RETAIN</code> policy, it uses servant managers that are <code>ServantActivator</code>s.

 132 </ul>
 133 
 134 
 135 <H2>Package <TT>org.omg.PortableServer.ServantLocatorPackage</TT></H2>
 136 
 137 <P>This package supplies a <TT>CookieHolder</TT> class for passing 
 138 the <TT>Cookie</TT> type as an <code>out</code> parameter. The <code>CookieHolder</code> class 
 139 follows exactly the same pattern as the other holder classes for basic types.
 140 
 141 <H2>Related Documentation</H2>
 142 
 143 <P>For an overview of Java IDL, please see:
 144 <P>
 145 <LI><A HREF="../../../../technotes/guides/idl/index.html">Java IDL home page</A>.
 146 
 147 <H2>Example Code</H2>
 148 <a name="sampleserver"></a>
 149 <H3>Example Server Code</H3>
 150 <P>
 151 <PRE>
 152 import javax.naming.InitialContext;
 153 import javax.naming.Context;
 154 import javax.rmi.PortableRemoteObject ;
 155 import com.sun.corba.se.impl.poa.POAORB;
 156 import org.omg.PortableServer.*;
 157 import java.util.*;
 158 import org.omg.CORBA.*;
 159 import javax.rmi.CORBA.Stub;
 160 import javax.rmi.CORBA.Util;
 161 
 162 
 163 
 164 public class HelloServer {
 165     public HelloServer(String[] args) {
 166         try {
 167             Properties p = System.getProperties();
 168          //   p.put("org.omg.CORBA.ORBClass", "com.sun.corba.ee.internal.POA.POAORB");
 169             ORB orb = ORB.init( args, p );
 170 


 190 
 191             Context initialNamingContext = new InitialContext();
 192             initialNamingContext.rebind("HelloService", helloRef);
 193             System.out.println("Hello Server: Ready...");
 194             orb.run();
 195          } catch (Exception e) {
 196             System.out.println("Trouble: " + e);
 197             e.printStackTrace();
 198          } 
 199      }
 200 
 201 
 202      public static void main(String args[]) {
 203          new HelloServer( args );
 204      }
 205 }
 206 
 207 
 208 </PRE>
 209 
 210 
 211 
 212 <P>
 213 
 214 
 215 @since 1.4
 216 <br>
 217 @serial exclude
 218 </body>
 219 </html>
   1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
   2 <html>
   3 <head>
   4 <!--
   5  
   6  Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
   7  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   8 
   9  This code is free software; you can redistribute it and/or modify it
  10  under the terms of the GNU General Public License version 2 only, as
  11  published by the Free Software Foundation.  Oracle designates this
  12  particular file as subject to the "Classpath" exception as provided
  13  by Oracle in the LICENSE file that accompanied this code.
  14 
  15  This code is distributed in the hope that it will be useful, but WITHOUT
  16  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  17  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  18  version 2 for more details (a copy is included in the LICENSE file that
  19  accompanied this code).
  20 
  21  You should have received a copy of the GNU General Public License version
  22  2 along with this work; if not, write to the Free Software Foundation,
  23  Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  24 
  25  Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  26  or visit www.oracle.com if you need additional information or have any


  35 portable across multivendor ORBs.
  36 
  37 <P>In Java, Portable Object Adaptor (POA)-based Dynamic Skeleton Interface (DSI) 
  38 servants inherit from the  standard <TT>DynamicImplementation</TT> class, which 
  39 inherits from the <TT>Servant</TT> class. The native <TT>Servant</TT> type is 
  40 defined by the <TT>PortableServer</TT> module for the POA. In Java, the 
  41   <TT>Servant</TT> type is mapped to the Java 
  42   <TT>org.omg.PortableServer.Servant</TT> class.
  43   It serves as the base class for all POA servant 
  44   implementations and provides a number of methods that may 
  45   be invoked by the application programmer, as well as methods 
  46   which are invoked by the POA itself and may be overridden by 
  47   the user to control aspects of servant behavior. 
  48   
  49 <H2>Package Specification</H2>
  50  
  51 <P>For a precise list of supported sections of official OMG specifications with which 
  52 the Java[tm] Platform, Standard Edition 6 complies, see <A 
  53 HREF="../CORBA/doc-files/compliance.html">Official Specifications for CORBA 
  54 support in Java[tm] SE 6</A>.

  55 
  56 <H2>POA-related Interfaces</H2>
  57 
  58 <P>The <TT>PortableServer</TT> module defines the following POA-related interfaces:

  59 <UL>
  60         <LI><TT>POA</TT>
  61         <LI><TT>POAManager</TT>
  62         <LI><TT>ServantManager</TT>
  63         <LI><TT>ServantActivator</TT>
  64         <LI><TT>ServantLocator</TT>
  65         <LI><TT>AdapterActivator</TT>
  66         <LI><TT>ThreadPolicy</TT>
  67         <LI><TT>LifespanPolicy</TT>
  68         <LI><TT>IdUniquenessPolicy</TT>
  69         <LI><TT>IdAssignmentPolicy</TT>
  70         <LI><TT>ImplicitActivationPolicy</TT>
  71         <LI><TT>ServantRetentionPolicy</TT>
  72         <LI><TT>RequestProcessingPolicy</TT>
  73         <LI><TT>Current</TT>
  74 </UL>
  75 
  76 <P>In addition, the POA defines the <TT>Servant</TT> native type.
  77 
  78 <H3>Operations classes</H3>
  79 
  80 <P>Each of the interfaces listed above has an associated <code>Operations</code> interface.
  81 The <code>Operations</code> interface is generated by the <code>idlj</code> compiler and
  82 contains the method signatures for methods defined in its associated interface.
  83 The <code>Operations</code> interface can be accessed by both the client and the server,
  84 while its associated interface can only be called by the client.
  85 
  86 <H3>Value Classes</H3>
  87 
  88 Classes ending in the suffix <code>PolicyValue</code> provide the values used
  89 for the <code>create_POA</code> call, which sets the policy for the POA. See
  90 the <a href="#sampleserver">sample code</a> below for a demonstration. 
  91 <code>PolicyValue</code> files include the following:
  92 <UL>
  93 <LI><code>IdAssignmentPolicyValue</code> 
  94 <LI><code>IdUniquenessPolicyValue</code>
  95 <LI><code>ImplicitActivationPolicyValue</code>
  96 <LI><code>LifespanPolicyValue</code>
  97 <LI><code>RequestProcessingPolicyValue</code>
  98 <LI><code>ServantRetentionPolicyValue</code>
  99 <LI><code>ThreadPolicyValue</code>
 100 </UL>
 101 
 102 <H3>Helper Classes</H3>
 103 
 104 <P>Helper classes, which are generated for all user-defined types in an OMG IDL 
 105 interface, supply static methods needed to manipulate those types.
 106 There is only one method in a helper class that an application programmer uses: 
 107 the  <code>narrow</code> method.  Only Java interfaces mapped from IDL interfaces 
 108 will have a helper class that includes a <code>narrow</code> method, so in
 109 the <code>PortableServer</code> package, only the following classes have a <code>narrow</code> method:
 110 <UL>
 111 <LI><code>ForwardRequestHelper</code>
 112 <LI><code>ServantActivatorHelper</code>
 113 <LI><code>ServantLocatorHelper</code>
 114 </UL>
 115 
 116 <H3>POA Classes</H3>
 117 
 118 <P>POA classes are used to implement the <code>ServantActivator</code> or <code>ServantLocator</code>.
 119 
 120 <H3>Exceptions</H3>
 121 
 122 <P>The <code>ForwardRequest</code> exception indicates to the ORB 
 123 that it is responsible for delivering the current request and
 124 subsequent <code>ForwardRequest</code> requests to the object denoted in the
 125 <code>forward_reference</code> member of the exception.
 126 
 127 <H3>Interfaces Implemented by the Application Programmer</H3>
 128 
 129 <P>Most of what <code>PortableServer</code> does is transparent to the user.
 130 The result is that programmers will use only a few of the interfaces mentioned above.
 131 The remaining interfaces will be provided by the ORB implementation.
 132 The interfaces of interest to application programmers are the following:
 133 <ul>
 134   <LI><code>AdapterActivator</code>
 135   <P>Adapter activators are associated with POAs. 
 136   An adapter activator supplies a POA with the ability to create child POAs on demand,
 137   as a side-effect of receiving a request that names the child POA (or one of its children),
 138   or when <code>find_POA</code> is called with an activate parameter value of <code>TRUE</code>.
 139   An application server that creates all its needed POAs at the beginning of execution
 140   does not need to use or provide an adapter activator; it is necessary
 141   only for the case in which POAs need to be created during request processing.
 142   <LI><code>ServantLocator</code>
 143   <P>When the POA has the <code>NON_RETAIN</code> policy,
 144   it uses servant managers that are <code>ServantLocator</code>s.
 145   <LI><code>ServantActivator</code>
 146   <P>When the POA has the <code>RETAIN</code> policy,
 147   it uses servant managers that are <code>ServantActivator</code>s.
 148 </ul>
 149 
 150 
 151 <H2>Package <TT>org.omg.PortableServer.ServantLocatorPackage</TT></H2>
 152 
 153 <P>This package supplies a <TT>CookieHolder</TT> class for passing 
 154 the <TT>Cookie</TT> type as an <code>out</code> parameter. The <code>CookieHolder</code> class 
 155 follows exactly the same pattern as the other holder classes for basic types.
 156 
 157 <H2>Related Documentation</H2>
 158 
 159 <P>For an overview of Java IDL, please see:
 160 <A HREF="../../../../technotes/guides/idl/index.html">Java IDL home page</A>.

 161 
 162 <H2>Example Code</H2>
 163 <a name="sampleserver"></a>
 164 <H3>Example Server Code</H3>

 165 <PRE>
 166 import javax.naming.InitialContext;
 167 import javax.naming.Context;
 168 import javax.rmi.PortableRemoteObject ;
 169 import com.sun.corba.se.impl.poa.POAORB;
 170 import org.omg.PortableServer.*;
 171 import java.util.*;
 172 import org.omg.CORBA.*;
 173 import javax.rmi.CORBA.Stub;
 174 import javax.rmi.CORBA.Util;
 175 
 176 
 177 
 178 public class HelloServer {
 179     public HelloServer(String[] args) {
 180         try {
 181             Properties p = System.getProperties();
 182          //   p.put("org.omg.CORBA.ORBClass", "com.sun.corba.ee.internal.POA.POAORB");
 183             ORB orb = ORB.init( args, p );
 184 


 204 
 205             Context initialNamingContext = new InitialContext();
 206             initialNamingContext.rebind("HelloService", helloRef);
 207             System.out.println("Hello Server: Ready...");
 208             orb.run();
 209          } catch (Exception e) {
 210             System.out.println("Trouble: " + e);
 211             e.printStackTrace();
 212          } 
 213      }
 214 
 215 
 216      public static void main(String args[]) {
 217          new HelloServer( args );
 218      }
 219 }
 220 
 221 
 222 </PRE>
 223 



 224 
 225 
 226 @since 1.4
 227 <br>
 228 @serial exclude
 229 </body>
 230 </html>
< prev index next >