001/* DynUnionOperations.java --
002   Copyright (C) 2005 Free Software Foundation, Inc.
003This file is part of GNU Classpath.
004
005GNU Classpath is free software; you can redistribute it and/or modify
006it under the terms of the GNU General Public License as published by
007the Free Software Foundation; either version 2, or (at your option)
008any later version.
009
010GNU Classpath is distributed in the hope that it will be useful, but
011WITHOUT ANY WARRANTY; without even the implied warranty of
012MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013General Public License for more details.
014
015You should have received a copy of the GNU General Public License
016along with GNU Classpath; see the file COPYING.  If not, write to the
017Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01802110-1301 USA.
019
020Linking this library statically or dynamically with other modules is
021making a combined work based on this library.  Thus, the terms and
022conditions of the GNU General Public License cover the whole
023combination.
024
025As a special exception, the copyright holders of this library give you
026permission to link this library with independent modules to produce an
027executable, regardless of the license terms of these independent
028modules, and to copy and distribute the resulting executable under
029terms of your choice, provided that you also meet, for each linked
030independent module, the terms and conditions of the license of that
031module.  An independent module is a module which is not derived from
032or based on this library.  If you modify this library, you may extend
033this exception to your version of the library, but you are not
034obligated to do so.  If you do not wish to do so, delete this
035exception statement from your version. */
036
037
038package org.omg.DynamicAny;
039
040import org.omg.CORBA.TCKind;
041import org.omg.DynamicAny.DynAnyPackage.InvalidValue;
042import org.omg.DynamicAny.DynAnyPackage.TypeMismatch;
043
044/**
045 * Defines the operations, applicable to the DynUnion. The DynUnion has only two
046 * valid positions:
047 * <ul>
048 * <li>0 - contains the discriminator of the union. The discriminator defines,
049 * which of the union variants is currently active.</li>
050 * <li>1 - contains the currently active variant of the union content (a union
051 * member). </li>
052 * </ul>
053 * The size of the union is normally 2. If the discriminator value defines no
054 * valid variant, the union consists of discriminator only, having the size 1.
055 *
056 * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org)
057 */
058public interface DynUnionOperations
059  extends DynAnyOperations
060{
061  /**
062   * <p>Get the value of discriminator, defining which content variant
063   * (member) is active.
064   * </p><p>
065   * In the current implementation, the later changes on the returned value
066   * alter the state of the union via implemented internal listener.
067   * </p>
068   */
069  DynAny get_discriminator();
070
071  /**
072   * <p>Set the value of discriminator, activating the member variant that is
073   * consistent with the discriminator value. If the current member variant
074   * matches the discriminator being set, it is unchanged. Otherwise, it is
075   * replaced by the matching member variant with fields, initialised to default
076   * values. The current position is set to 0 if the discriminator value does
077   * not match any member variant. Otherwise, the current position is set to 1,
078   * index of the member variant.
079   * </p>
080   * @throws TypeMismatch if the discriminator has a wrong type of this union.
081   */
082  void set_discriminator(DynAny aDiscriminator)
083                  throws TypeMismatch;
084
085  /**
086   * Get the kind of the union descriminator.
087   *
088   * @return the TCKind value of the discriminator typecode.
089   */
090  TCKind discriminator_kind();
091
092  /**
093   * Get the current variant of the union content.
094   *
095   * @return the current member of the union. This reference is only valid as
096   * long as the current member does not change.
097   *
098   * @throws InvalidValue if the union has no active member.
099   */
100  DynAny member()
101         throws InvalidValue;
102
103  /**
104   * Returns the kind of the currently active union member.
105   *
106   * @return the TCKind value of the union member.
107   *
108   * @throws InvalidValue if the union has no active member.
109   */
110  TCKind member_kind()
111              throws InvalidValue;
112
113  /**
114   * Returns the name of the currently active union member.
115   *
116   * @return the TCKind value of the union member.
117   *
118   * @throws InvalidValue if the union has no active member.
119   */
120  String member_name()
121              throws InvalidValue;
122
123  /**
124   * Returns true if the union has no active member. This happens if If the
125   * discriminator value defines no valid variant. Such union consists of
126   * discriminator only, having the size 1.
127   */
128  boolean has_no_active_member();
129
130  /**
131   * Set the discriminator to default value. The current position is set to 0.
132   * This also sets the content variant to the default variant, and the size of
133   * the union becomes 2.
134   *
135   * @throws TypeMismatch if the default case is not defined for this union.
136   */
137  void set_to_default_member()
138                      throws TypeMismatch;
139
140  /**
141   * Set the discriminator to value that does not correspond any content variant
142   * (any union <code>case</code> label). The current position is set to 0.
143   * The size of the union becomes 0.
144   *
145   * @throws TypeMismatch if the union has explicit default case.
146   */
147  void set_to_no_active_member()
148                        throws TypeMismatch;
149}