001    /* InputStream.java --
002       Copyright (C) 2005, 2006 Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package org.omg.CORBA_2_3.portable;
040    
041    import gnu.CORBA.CDR.Vio;
042    
043    import org.omg.CORBA.CustomMarshal;
044    import org.omg.CORBA.portable.BoxedValueHelper;
045    import org.omg.CORBA.portable.StreamableValue;
046    
047    import 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     */
065    public 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    }