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 27 questions. 28 29 30 --> 31 32 </head> 33 <body bgcolor="white"> 34 Provides classes and interfaces for making the server side of your applications 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 ); 170 171 POA rootPOA = (POA)orb.resolve_initial_references("RootPOA"); 172 <strong> 173 Policy[] tpolicy = new Policy[3]; 174 tpolicy[0] = rootPOA.create_lifespan_policy( 175 LifespanPolicyValue.TRANSIENT ); 176 tpolicy[1] = rootPOA.create_request_processing_policy( 177 RequestProcessingPolicyValue.USE_ACTIVE_OBJECT_MAP_ONLY ); 178 tpolicy[2] = rootPOA.create_servant_retention_policy( 179 ServantRetentionPolicyValue.RETAIN); 180 POA tpoa = rootPOA.create_POA("MyTransientPOA", null, tpolicy); 181 </strong> 182 183 String ObjectId = "MyObjectId"; 184 byte[] oid = ObjectId.getBytes(); 185 186 org.omg.CORBA.Object obj = tpoa.create_reference_with_id(oid, 187 new _HelloImpl_Tie()._all_interfaces(tpoa, oid)[0]); 188 HelloInterface helloRef = (HelloInterface)PortableRemoteObject.narrow( 189 obj, HelloInterface.class ); 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>