001/* CommandMap.java -- Registry of available command objects.
002   Copyright (C) 2004, 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
038package javax.activation;
039
040/**
041 * Registry of command objects available to the system.
042 *
043 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
044 * @version 1.1
045 */
046public abstract class CommandMap
047{
048
049  /* Class scope */
050
051  private static CommandMap defaultCommandMap;
052
053  /**
054   * Returns the default command map.
055   * This returns a MailcapCommandMap if no value has been set using
056   * <code>setDefaultCommandMap</code>.
057   */
058  public static CommandMap getDefaultCommandMap()
059  {
060    if (defaultCommandMap == null)
061      {
062        defaultCommandMap = new MailcapCommandMap();
063      }
064    return defaultCommandMap;
065  }
066
067  /**
068   * Sets the default command map.
069   * @param commandMap the new default command map
070   */
071  public static void setDefaultCommandMap(CommandMap commandMap)
072  {
073    SecurityManager security = System.getSecurityManager();
074    if (security != null)
075      {
076        try
077          {
078            security.checkSetFactory();
079          }
080        catch (SecurityException e)
081          {
082            if (commandMap != null && CommandMap.class.getClassLoader() !=
083                commandMap.getClass().getClassLoader())
084              {
085                throw e;
086              }
087          }
088      }
089    defaultCommandMap = commandMap;
090  }
091
092  /* Instance scope */
093
094  /**
095   * Returns the list of preferred commands for a MIME type.
096   * @param mimeType the MIME type
097   */
098  public abstract CommandInfo[] getPreferredCommands(String mimeType);
099
100  /**
101   * Returns the complete list of commands for a MIME type.
102   * @param mimeType the MIME type
103   */
104  public abstract CommandInfo[] getAllCommands(String mimeType);
105
106  /**
107   * Returns the command corresponding to the specified MIME type and
108   * command name.
109   * @param mimeType the MIME type
110   * @param cmdName the command name
111   */
112  public abstract CommandInfo getCommand(String mimeType, String cmdName);
113
114  /**
115   * Returns a DataContentHandler corresponding to the MIME type.
116   * @param mimeType the MIME type
117   */
118  public abstract DataContentHandler createDataContentHandler(String mimeType);
119
120  /**
121   * Get all the MIME types known to this command map.
122   * If the command map doesn't support this operation, null is returned.
123   * @return array of MIME types as strings, or null if not supported
124   * @since JAF 1.1
125   */
126  public String[] getMimeTypes()
127  {
128    return null;
129  }
130
131  /**
132   * Get the preferred command list from a MIME Type. The actual semantics
133   * are determined by the implementation of the CommandMap.
134   * <p>
135   * The <code>DataSource</code> provides extra information, such as
136   * the file name, that a CommandMap implementation may use to further
137   * refine the list of commands that are returned.  The implementation
138   * in this class simply calls the <code>getPreferredCommands</code>
139   * method that ignores this argument.
140   * @param mimeType the MIME type
141   * @param ds a DataSource for the data
142   * @return the CommandInfo classes that represent the command Beans.
143   * @since JAF 1.1
144   */
145  public CommandInfo[] getPreferredCommands(String mimeType,
146                                            DataSource ds)
147  {
148    return getPreferredCommands(mimeType);
149  }
150
151  /**
152   * Get all the available commands for this type. This method
153   * should return all the possible commands for this MIME type.
154   * <p>
155   * The <code>DataSource</code> provides extra information, such as
156   * the file name, that a CommandMap implementation may use to further
157   * refine the list of commands that are returned.  The implementation
158   * in this class simply calls the <code>getAllCommands</code>
159   * method that ignores this argument.
160   * @param mimeType the MIME type
161   * @param ds a DataSource for the data
162   * @return the CommandInfo objects representing all the commands.
163   * @since JAF 1.1
164   */
165  public CommandInfo[] getAllCommands(String mimeType, DataSource ds)
166  {
167    return getAllCommands(mimeType);
168  }
169
170  /**
171   * Get the default command corresponding to the MIME type.
172   * <p>
173   * The <code>DataSource</code> provides extra information, such as
174   * the file name, that a CommandMap implementation may use to further
175   * refine the command that is chosen.  The implementation
176   * in this class simply calls the <code>getCommand</code>
177   * method that ignores this argument.
178   * @param mimeType the MIME type
179   * @param cmdName the command name
180   * @param ds a DataSource for the data
181   * @return the CommandInfo corresponding to the command.
182   * @since JAF 1.1
183   */
184  public CommandInfo getCommand(String mimeType, String cmdName,
185                                DataSource ds)
186  {
187    return getCommand(mimeType, cmdName);
188  }
189
190  /**
191   * Locate a DataContentHandler that corresponds to the MIME type.
192   * The mechanism and semantics for determining this are determined
193   * by the implementation of the particular CommandMap.
194   * <p>
195   * The <code>DataSource</code> provides extra information, such as
196   * the file name, that a CommandMap implementation may use to further
197   * refine the choice of DataContentHandler.  The implementation
198   * in this class simply calls the <code>createDataContentHandler</code>
199   * method that ignores this argument.
200   * @param mimeType the MIME type
201   * @param ds a DataSource for the data
202   * @return the DataContentHandler for the MIME type
203   * @since JAF 1.1
204   */
205  public DataContentHandler createDataContentHandler(String mimeType,
206                                                     DataSource ds)
207  {
208    return createDataContentHandler(mimeType);
209  }
210
211}