Servant.java revision 608:7e06bf1dcb09 
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25package org.omg.PortableServer;
26
27import org.omg.CORBA.ORB;
28import org.omg.PortableServer.portable.Delegate;
29
30/**
31 * Defines the native <code>Servant</code> type. In Java, the
32 * <code>Servant</code> type is mapped to the Java
33 * <code>org.omg.PortableServer.Servant</code> class.
34 * It serves as the base class for all POA servant
35 * implementations and provides a number of methods that may
36 * be invoked by the application programmer, as well as methods
37 * which are invoked by the POA itself and may be overridden by
38 * the user to control aspects of servant behavior.
39 * Based on IDL to Java spec. (CORBA V2.3.1) ptc/00-01-08.pdf.
40 */
41
42abstract public class Servant {
43
44    private transient Delegate _delegate = null;
45    /**
46     * Gets the ORB vendor-specific implementation of
47     * <code>PortableServer::Servant</code>.
48     * @return <code>_delegate</code> the ORB vendor-specific
49     * implementation of <code>PortableServer::Servant</code>.
50     */
51    final public Delegate _get_delegate() {
52        if (_delegate == null) {
53            throw
54                new
55                org.omg.CORBA.BAD_INV_ORDER
56                ("The Servant has not been associated with an ORB instance");
57        }
58        return _delegate;
59    }
60
61    /**
62     * Supports the Java ORB portability
63     * interfaces by providing a method for classes that support
64     * ORB portability through delegation to set their delegate.
65     * @param delegate ORB vendor-specific implementation of
66     *                 the <code>PortableServer::Servant</code>.
67     */
68    final public void _set_delegate(Delegate delegate) {
69        _delegate = delegate;
70    }
71
72    /**
73     * Allows the servant to obtain the object reference for
74     * the target CORBA object it is incarnating for that request.
75     * @return <code>this_object</code> <code>Object</code> reference
76     * associated with the request.
77     */
78    final public org.omg.CORBA.Object _this_object() {
79        return _get_delegate().this_object(this);
80    }
81
82    /**
83     * Allows the servant to obtain the object reference for
84     * the target CORBA Object it is incarnating for that request.
85     * @param orb ORB with which the servant is associated.
86     * @return <code>_this_object</code> reference associated with the request.
87     */
88    final public org.omg.CORBA.Object _this_object(ORB orb) {
89        try {
90            ((org.omg.CORBA_2_3.ORB)orb).set_delegate(this);
91        }
92        catch(ClassCastException e) {
93            throw
94                new
95                org.omg.CORBA.BAD_PARAM
96                ("POA Servant requires an instance of org.omg.CORBA_2_3.ORB");
97        }
98        return _this_object();
99    }
100
101    /**
102     * Returns the instance of the ORB
103     * currently associated with the <code>Servant</code> (convenience method).
104     * @return <code>orb</code> the instance of the ORB currently
105     * associated with the <code>Servant</code>.
106     */
107    final public ORB _orb() {
108        return _get_delegate().orb(this);
109    }
110
111    /**
112     * Allows easy execution of common methods, equivalent to
113     * <code>PortableServer::Current:get_POA</code>.
114     * @return <code>poa</code> POA associated with the servant.
115     */
116    final public POA _poa() {
117        return _get_delegate().poa(this);
118    }
119
120    /**
121     * Allows easy execution of
122     * common methods, equivalent
123     * to calling <code>PortableServer::Current::get_object_id</code>.
124     * @return <code>object_id</code> the <code>Object</code> ID associated
125     * with this servant.
126     */
127    final public byte[] _object_id() {
128        return _get_delegate().object_id(this);
129    }
130
131    /**
132     * Returns the
133     * root POA from the ORB instance associated with the servant.
134     * Subclasses may override this method to return a different POA.
135     * @return <code>default_POA</code> the POA associated with the
136     * <code>Servant</code>.
137     */
138    public POA _default_POA() {
139        return _get_delegate().default_POA(this);
140    }
141
142    /**
143     * Checks to see if the specified <code>repository_id</code> is present
144     * on the list returned by <code>_all_interfaces()</code> or is the
145     * <code>repository_id</code> for the generic CORBA Object.
146     * @param repository_id the <code>repository_id</code>
147     *          to be checked in the repository list or against the id
148     *          of generic CORBA objects.
149     * @return <code>is_a</code> boolean indicating whether the specified
150     *          <code>repository_id</code> is
151     *         in the repository list or is same as a generic CORBA
152     *         object.
153     */
154    public boolean _is_a(String repository_id) {
155        return _get_delegate().is_a(this, repository_id);
156    }
157
158    /**
159     * Checks for the existence of an
160     * <code>Object</code>.
161     * The <code>Servant</code> provides a default implementation of
162     * <code>_non_existent()</code> that can be overridden by derived servants.
163     * @return <code>non_existent</code> <code>true</code> if that object does
164     *           not exist,  <code>false</code> otherwise.
165     */
166    public boolean _non_existent() {
167        return _get_delegate().non_existent(this);
168    }
169
170    // Ken and Simon will ask about editorial changes
171    // needed in IDL to Java mapping to the following
172    // signature.
173    /**
174     * Returns an object in the Interface Repository
175     * which provides type information that may be useful to a program.
176     * <code>Servant</code> provides a default implementation of
177     * <code>_get_interface()</code>
178     * that can be overridden by derived servants if the default
179     * behavior is not adequate.
180     * @return <code>get_interface</code> type information that corresponds to this servant.
181     */
182    /*
183    public org.omg.CORBA.Object _get_interface() {
184        return _get_delegate().get_interface(this);
185    }
186    */
187
188    // _get_interface_def() replaces the _get_interface() method
189
190    /**
191     * Returns an <code>InterfaceDef</code> object as a
192     * <code>CORBA::Object</code> that defines the runtime type of the
193     * <code>CORBA::Object</code> implemented by the <code>Servant</code>.
194     * The invoker of <code>_get_interface_def</code>
195     * must narrow the result to an <code>InterfaceDef</code> in order
196     * to use it.
197     * <P>This default implementation of <code>_get_interface_def()</code>
198     * can be overridden
199     * by derived servants if the default behavior is not adequate.
200     * As defined in the CORBA 2.3.1 specification, section 11.3.1, the
201     * default behavior of <code>_get_interface_def()</code> is to use
202     * the most derived
203     * interface of a static servant or the most derived interface retrieved
204     * from a dynamic servant to obtain the <code>InterfaceDef</code>.
205     * This behavior must
206     * be supported by the <code>Delegate</code> that implements the
207     * <code>Servant</code>.
208     * @return <code>get_interface_def</code> an <code>InterfaceDef</code>
209     * object as a
210     * <code>CORBA::Object</code> that defines the runtime type of the
211     * <code>CORBA::Object</code> implemented by the <code>Servant</code>.
212     */
213    public org.omg.CORBA.Object _get_interface_def()
214    {
215        // First try to call the delegate implementation class's
216        // "Object get_interface_def(..)" method (will work for ORBs
217        // whose delegates implement this method).
218        // Else call the delegate implementation class's
219        // "InterfaceDef get_interface(..)" method using reflection
220        // (will work for ORBs that were built using an older version
221        // of the Delegate interface with a get_interface method
222        // but not a get_interface_def method).
223
224        org.omg.PortableServer.portable.Delegate delegate = _get_delegate();
225        try {
226            // If the ORB's delegate class does not implement
227            // "Object get_interface_def(..)", this will throw
228            // an AbstractMethodError.
229            return delegate.get_interface_def(this);
230        } catch( AbstractMethodError aex ) {
231            // Call "InterfaceDef get_interface(..)" method using reflection.
232            try {
233                Class[] argc = { org.omg.PortableServer.Servant.class };
234                java.lang.reflect.Method meth =
235                     delegate.getClass().getMethod("get_interface", argc);
236                Object[] argx = { this };
237                return (org.omg.CORBA.Object)meth.invoke(delegate, argx);
238            } catch( java.lang.reflect.InvocationTargetException exs ) {
239                Throwable t = exs.getTargetException();
240                if (t instanceof Error) {
241                    throw (Error) t;
242                } else if (t instanceof RuntimeException) {
243                    throw (RuntimeException) t;
244                } else {
245                    throw new org.omg.CORBA.NO_IMPLEMENT();
246                }
247            } catch( RuntimeException rex ) {
248                throw rex;
249            } catch( Exception exr ) {
250                throw new org.omg.CORBA.NO_IMPLEMENT();
251            }
252        }
253    }
254
255    // methods for which the user must provide an
256    // implementation
257    /**
258     * Used by the ORB to obtain complete type
259     * information from the servant.
260     * @param poa POA with which the servant is associated.
261     * @param objectId is the id corresponding to the object
262     *         associated with this servant.
263     * @return list of type information for the object.
264     */
265    abstract public String[] _all_interfaces( POA poa, byte[] objectId);
266}
267