001/* InputStream.java --
002   Copyright (C) 2005, 2006 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package org.omg.CORBA_2_3.portable;
040
041import gnu.CORBA.CDR.Vio;
042
043import org.omg.CORBA.CustomMarshal;
044import org.omg.CORBA.portable.BoxedValueHelper;
045import org.omg.CORBA.portable.StreamableValue;
046
047import java.io.Serializable;
048
049/**
050 * This class defines a new CDR input stream methods, added since
051 * CORBA 2.3.
052 *
053 * This class is abstract; no direct instances can be instantiated.
054 * Also, up till v 1.4 inclusive there are no methods that would
055 * return it, and only one unimplemented interface,
056 * {@link org.omg.CORBA.portable.ValueFactory }, needs it as a parameter.
057 *
058 * However since 1.3 all methods, declared as returning an
059 * org.omg.CORBA.portable.InputStream actually return the instance of this
060 * derived class and the new methods are accessible after the casting
061 * operation.
062 *
063 * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org)
064 */
065public abstract class InputStream
066  extends org.omg.CORBA.portable.InputStream
067{
068  /**
069   * Read the abstract interface. An abstract interface can be either
070   * CORBA value type or CORBA object and is returned as an abstract
071   * java.lang.Object.
072   *
073   * As specified in OMG specification, this reads a single
074   * boolean and then delegates either to {@link #read_Object()} (for false)
075   * or to {@link #read_value()} (for true).
076   *
077   * @return an abstract interface, unmarshaled from the stream.
078   */
079  public Object read_abstract_interface()
080  {
081    boolean isObject = read_boolean();
082
083    if (isObject)
084      return read_Object();
085    else
086      return read_value();      
087  }
088
089  /**
090   * Read the abstract interface, corresponding to the passed type.
091   * An abstract interface can be either CORBA value type or CORBA
092   * object and is returned as an abstract java.lang.Object.
093   *
094   * As specified in OMG specification, this reads a single
095   * boolean and then delegates either to {@link #read_Object(Class)} (for false)
096   * or to {@link #read_value(Class)} (for true).
097   *
098   * @param clz a base class for the abstract interface.
099   *
100   * @return an abstract interface, unmarshaled from the stream
101   */
102  public Object read_abstract_interface(Class clz)
103  {
104    boolean isValue = read_boolean();
105
106    if (isValue)
107      return read_value(clz);
108    else
109      return read_Object(clz);
110  }
111
112  /**
113   * Read a value type structure, extracting the repository id
114   * from the input stream itself. The repository id is optional
115   * in the value type record, but it  must be present for this
116   * method to succeed. The {@link OutputStream} of this
117   * implementation always stores the repository id.
118   *
119   * The casts the streams ORB into a CORBA 2.3 ORB and then
120   * searched for a suitable value factory, where it delegates
121   * the functionality.
122   *
123   * If you know the exact class or can create an unitialised instance
124   * of the value type, it is recommended (faster) to use
125   * {@link #read_value(Class)} or {@link #read_value(Serializable)}
126   * instead.
127   *
128   * @return an value type structure, unmarshaled from the stream
129   */
130  public Serializable read_value()
131  {
132    return Vio.read(this);
133  }
134
135  /**
136   * Read a value type structure, corresponing to the passed type.
137   * As the type is known, the repository Id in the input stream is
138   * optional an not required. The codebase, if present, is also ignored.
139   *
140   * The passed class must implement either {@link CustomMarshal}
141   * for the user-defined reading operations or {@link StreamableValue}
142   * for the standard (generated by IDL compiler) reading operations.
143   * Also, it must have the parameterless constructor to create a new
144   * instance.
145   *
146   * @param clz a base class for a value type.
147   *
148   * @return an value type structure, unmarshaled from the stream
149   */
150  public Serializable read_value(Class clz)
151  {
152    return Vio.read(this, clz);
153  }
154
155  /**
156   * Read a value type structure content, when the unitialised
157   * instance is passed as a parameter. It is a fastest method to read
158   * a value type.
159   *
160   * As the type is known, the repository Id in the input stream is
161   * optional an not required. The codebase, if present, is also ignored.
162   *
163   * The passed instance must implement either {@link CustomMarshal}
164   * for the user-defined reading operations or {@link StreamableValue}
165   * for the standard (generated by IDL compiler) reading operations.
166   *
167   * @param unitialised_value the unitialised value.
168   *
169   * @return same value, filled in by the stream content.
170   */
171  public Serializable read_value(Serializable unitialised_value)
172  {
173    return (Serializable) Vio.read(this, unitialised_value, null);
174  }
175
176  /**
177   * Read a value type structure, having the given repository id.
178   * The casts the streams ORB into a CORBA 2.3 ORB and then
179   * searched for a suitable value factory, where it delegates
180   * the functionality.
181   *
182   * If you know the exact class or can create an unitialised instance
183   * of the value type, it is recommended (faster) to use
184   * {@link #read_value(Class)} or {@link #read_value(Serializable)}
185   * instead.
186   *
187   * @param repository_id a repository id of the value type.
188   *
189   * @return an value type structure, unmarshaled from the stream
190   */
191  public Serializable read_value(String repository_id)
192  {
193    return Vio.read(this, repository_id);
194  }
195
196  /**
197   * Use the provided boxed value helper to read the value.
198   *
199   * @param helper a helper for reading the value from the stream.
200   *
201   * @return an value type structure, unmarshaled from the stream.
202   */
203  public Serializable read_value(BoxedValueHelper helper)
204  {
205    return Vio.read(this, helper);
206  }
207}