Request.java revision 608:7e06bf1dcb09 
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25
26package org.omg.CORBA;
27
28/**
29 * An object containing the information necessary for
30 * invoking a method.  This class is
31 * the cornerstone of the ORB Dynamic
32 * Invocation Interface (DII), which allows dynamic creation and
33 * invocation of requests.
34 * A server cannot tell the difference between a client
35 * invocation using a client stub and a request using the DII.
36 * <P>
37 * A <code>Request</code> object consists of:
38 * <UL>
39 * <LI>the name of the operation to be invoked
40 * <LI>an <code>NVList</code> containing arguments for the operation.<BR>
41 * Each item in the list is a <code>NamedValue</code> object, which has three
42 * parts:
43 *  <OL>
44 *    <LI>the name of the argument
45 *    <LI>the value of the argument (as an <code>Any</code> object)
46 *    <LI>the argument mode flag indicating whether the argument is
47 *        for input, output, or both
48 *  </OL>
49 * </UL>
50 * <P>
51 * <code>Request</code> objects may also contain additional information,
52 * depending on how an operation was defined in the original IDL
53 * interface definition.  For example, where appropriate, they may contain
54 * a <code>NamedValue</code> object to hold the return value or exception,
55 * a context, a list of possible exceptions, and a list of
56 * context strings that need to be resolved.
57 * <P>
58 * New <code>Request</code> objects are created using one of the
59 * <code>create_request</code> methods in the <code>Object</code> class.
60 * In other words, a <code>create_request</code> method is performed on the
61 * object which is to be invoked.
62 *
63 * @see org.omg.CORBA.NamedValue
64 *
65 */
66
67public abstract class Request {
68
69    /**
70     * Retrieves the the target object reference.
71     *
72     * @return                  the object reference that points to the
73     *                    object implementation for the method
74     *                    to be invoked
75     */
76
77    public abstract org.omg.CORBA.Object target();
78
79    /**
80     * Retrieves the name of the method to be invoked.
81     *
82     * @return                  the name of the method to be invoked
83     */
84
85    public abstract String operation();
86
87    /**
88     * Retrieves the <code>NVList</code> object containing the arguments
89     * to the method being invoked.  The elements in the list are
90     * <code>NamedValue</code> objects, with each one describing an argument
91     * to the method.
92     *
93     * @return  the <code>NVList</code> object containing the arguments
94     *                  for the method
95     *
96     */
97
98    public abstract NVList arguments();
99
100    /**
101     * Retrieves the <code>NamedValue</code> object containing the return
102     * value for the method.
103     *
104     * @return          the <code>NamedValue</code> object containing the result
105     *                          of the method
106     */
107
108    public abstract NamedValue result();
109
110    /**
111     * Retrieves the <code>Environment</code> object for this request.
112     * It contains the exception that the method being invoked has
113     * thrown (after the invocation returns).
114     *
115     *
116     * @return  the <code>Environment</code> object for this request
117     */
118
119    public abstract Environment env();
120
121    /**
122     * Retrieves the <code>ExceptionList</code> object for this request.
123     * This list contains <code>TypeCode</code> objects describing the
124     * exceptions that may be thrown by the method being invoked.
125     *
126     * @return  the <code>ExceptionList</code> object describing the exceptions
127     *            that may be thrown by the method being invoked
128     */
129
130    public abstract ExceptionList exceptions();
131
132    /**
133     * Retrieves the <code>ContextList</code> object for this request.
134     * This list contains context <code>String</code>s that need to
135     * be resolved and sent with the invocation.
136     *
137     *
138     * @return                  the list of context strings whose values
139     *                          need to be resolved and sent with the
140     *                          invocation.
141     */
142
143    public abstract ContextList contexts();
144
145    /**
146     * Retrieves the <code>Context</code> object for this request.
147     * This is a list of properties giving information about the
148     * client, the environment, or the circumstances of this request.
149     *
150     * @return          the <code>Context</code> object that is to be used
151     *                          to resolve any context strings whose
152     *                          values need to be sent with the invocation
153     */
154
155    public abstract Context ctx();
156
157    /**
158     * Sets this request's <code>Context</code> object to the one given.
159     *
160     * @param c         the new <code>Context</code> object to be used for
161     *                          resolving context strings
162     */
163
164    public abstract void ctx(Context c);
165
166
167    /**
168     * Creates an input argument and adds it to this <code>Request</code>
169     * object.
170     *
171     * @return          an <code>Any</code> object that contains the
172     *                value and typecode for the input argument added
173     */
174
175    public abstract Any add_in_arg();
176
177    /**
178     * Creates an input argument with the given name and adds it to
179     * this <code>Request</code> object.
180     *
181     * @param name              the name of the argument being added
182     * @return          an <code>Any</code> object that contains the
183     *                value and typecode for the input argument added
184     */
185
186    public abstract Any add_named_in_arg(String name);
187
188    /**
189     * Adds an input/output argument to this <code>Request</code> object.
190     *
191     * @return          an <code>Any</code> object that contains the
192     *                value and typecode for the input/output argument added
193     */
194
195    public abstract Any add_inout_arg();
196
197    /**
198     * Adds an input/output argument with the given name to this
199     * <code>Request</code> object.
200     *
201     * @param name              the name of the argument being added
202     * @return          an <code>Any</code> object that contains the
203     *                value and typecode for the input/output argument added
204     */
205
206    public abstract Any add_named_inout_arg(String name);
207
208
209    /**
210     * Adds an output argument to this <code>Request</code> object.
211     *
212     * @return          an <code>Any</code> object that contains the
213     *                value and typecode for the output argument added
214     */
215
216    public abstract Any add_out_arg();
217
218    /**
219     * Adds an output argument with the given name to this
220     * <code>Request</code> object.
221     *
222     * @param name              the name of the argument being added
223     * @return          an <code>Any</code> object that contains the
224     *                value and typecode for the output argument added
225     */
226
227    public abstract Any add_named_out_arg(String name);
228
229    /**
230     * Sets the typecode for the return
231     * value of the method.
232     *
233     * @param tc                        the <code>TypeCode</code> object containing type information
234     *                   for the return value
235     */
236
237    public abstract void set_return_type(TypeCode tc);
238
239    /**
240     * Returns the <code>Any</code> object that contains the value for the
241     * result of the method.
242     *
243     * @return                  an <code>Any</code> object containing the value and
244     *                   typecode for the return value
245     */
246
247    public abstract Any return_value();
248
249    /**
250     * Makes a synchronous invocation using the
251     * information in the <code>Request</code> object. Exception information is
252     * placed into the <code>Request</code> object's environment object.
253     */
254
255    public abstract void invoke();
256
257    /**
258     * Makes a oneway invocation on the
259     * request. In other words, it does not expect or wait for a
260     * response. Note that this can be used even if the operation was
261     * not declared as oneway in the IDL declaration. No response or
262     * exception information is returned.
263     */
264
265    public abstract void send_oneway();
266
267    /**
268     * Makes an asynchronous invocation on
269     * the request. In other words, it does not wait for a response before it
270     * returns to the user. The user can then later use the methods
271     * <code>poll_response</code> and <code>get_response</code> to get
272     * the result or exception information for the invocation.
273     */
274
275    public abstract void send_deferred();
276
277    /**
278     * Allows the user to determine
279     * whether a response has been received for the invocation triggered
280     * earlier with the <code>send_deferred</code> method.
281     *
282     * @return          <code>true</code> if the method response has
283     *                          been received; <code>false</code> otherwise
284     */
285
286    public abstract boolean poll_response();
287
288    /**
289     * Allows the user to access the
290     * response for the invocation triggered earlier with the
291     * <code>send_deferred</code> method.
292     *
293     * @exception WrongTransaction  if the method <code>get_response</code> was invoked
294     * from a different transaction's scope than the one from which the
295     * request was originally sent. See the OMG Transaction Service specification
296     * for details.
297     */
298
299    public abstract void get_response() throws WrongTransaction;
300
301};
302