001/* StringHolder.java --
002   Copyright (C) 2005 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;
040
041import gnu.CORBA.typecodes.StringTypeCode;
042
043import org.omg.CORBA.portable.InputStream;
044import org.omg.CORBA.portable.OutputStream;
045import org.omg.CORBA.portable.Streamable;
046
047/**
048 * A holder for CORBA <code>string</code> that is mapped into
049 * java <code>String</code>.
050 *
051 * The holders have several application areas. The end user usually
052 * sees them implementing CORBA methods where the primitive type
053 * is passed by reference. While CORBA (or, for example, C) supports
054 * this, the java does not and a wrapper class is required.
055 *
056 * @author Audrius Meskauskas (AudriusA@Bioinformatics.org)
057 */
058public final class StringHolder
059  implements Streamable
060{
061  /**
062   * The default type code for this holder.
063   */
064  private static final StringTypeCode t_string =
065    new StringTypeCode(TCKind.tk_string);
066
067  /**
068   * The <code>String</code> (CORBA <code>string</code>) value,
069   * held by this StringHolder.
070   */
071  public String value;
072
073  /**
074   * Constructs an instance of StringHolder,
075   * initializing {@link #value} to <code>null</code>.
076   */
077  public StringHolder()
078  {
079  }
080
081  /**
082   * Constructs an instance of StringHolder,
083   * initializing {@link #value} to the given <code>String</code>.
084   *
085   * @param initial_value a value that will be assigned to the
086   * {@link #value} field.
087   */
088  public StringHolder(String initial_value)
089  {
090    value = initial_value;
091  }
092
093  /**
094   * Fill in the {@link #value } field by reading the required data
095   * from the given stream. For <code>string</code>, the functionality
096   * is delegated to
097   * {@link org.omg.CORBA.portable.InputStream#read_string}.
098   *
099   * @param input the input stream to read from.
100   */
101  public void _read(InputStream input)
102  {
103    value = input.read_string();
104  }
105
106  /**
107   * Returns the TypeCode, corresponding the CORBA type that is stored
108   * using this holder. The {@link TypeCode#length()} method of the
109   * returned typecode always returns 0.
110   */
111  public TypeCode _type()
112  {
113    return t_string;
114  }
115
116  /**
117   * Write the {@link #value } field to the given stream.
118   * For <code>string</code>, the functionality
119   * is delegated to
120   * {@link org.omg.CORBA.portable.OutputStream#write_string(String) }.
121   *
122   * @param output the output stream to write into.
123   */
124  public void _write(OutputStream output)
125  {
126    output.write_string(value);
127  }
128}