001    /* OpenType.java -- Superclass of all open types.
002       Copyright (C) 2006, 2007 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    package javax.management.openmbean;
039    
040    import java.io.Serializable;
041    
042    import java.util.Arrays;
043    import java.util.List;
044    
045    /**
046     * The superclass of all open types, which describe the
047     * applicable data values for open MBeans.  An open type
048     * is defined by its name and description, and the name
049     * of the Java class it maps to.
050     *
051     * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
052     * @since 1.5
053     */
054    public abstract class OpenType<T>
055      implements Serializable
056    {
057    
058      /**
059       * Compatible with JDK 1.5
060       */
061      private static final long serialVersionUID = -9195195325186646468L;
062    
063      /**
064       * The name of the Java class this type represents.
065       */
066      private String className;
067    
068      /**
069       * The name of this type.
070       */
071      private String typeName;
072    
073      /**
074       * A description of this type.
075       */
076      private String description;
077    
078      /**
079       * An array which defines the set of Java types which can be
080       * used as open types.  Note that each type is also available
081       * in array form, possibly with multiple dimensions.
082       *
083       * @deprecated Use {@link ALLOWED_CLASSNAMES_LIST} instead.
084       */
085      @Deprecated
086      public static final String[] ALLOWED_CLASSNAMES = {
087        "java.lang.Void",
088        "java.lang.Boolean",
089        "java.lang.Character",
090        "java.lang.Byte",
091        "java.lang.Short",
092        "java.lang.Integer",
093        "java.lang.Long",
094        "java.lang.Float",
095        "java.lang.Double",
096        "java.lang.String",
097        "java.math.BigDecimal",
098        "java.math.BigInteger",
099        "java.util.Date",
100        "javax.management.ObjectName",
101        CompositeData.class.getName(),
102        TabularData.class.getName()
103      };
104    
105      /**
106       * A list which defines the set of Java types that may be
107       * used as open types.  Note that each type is also available
108       * in array form, possibly with multiple dimensions.
109       */
110      public static final List<String> ALLOWED_CLASSNAMES_LIST =
111        Arrays.asList(ALLOWED_CLASSNAMES);
112    
113      /**
114       * Constructs a new {@link OpenType} for the specified class
115       * with the given name and description.  The name of the class
116       * must be taken from the list of {@link ALLOWED_CLASSNAMES}.
117       * Arrays are implictly included in this, and follow the usual
118       * syntax of {@link java.lang.Class#getName()} with the name
119       * preceded by n instances of '[' (where n is the number of
120       * dimensions) and an L.  The name and description can not be
121       * <code>null</code> or the empty string.
122       *
123       * @param className the name of the Java class this type
124       *                  represents.
125       * @param name the name of the type.
126       * @param desc the description of the type.
127       * @throws IllegalArgumentException if either of <code>name</code>
128       *                                  or <code>desc</code> are
129       *                                  <code>null</code> or the empty
130       *                                  string.
131       * @throws OpenDataException if the class name does not reference
132       *                           a listed class (from @{link ALLOWED_CLASSNAMES})
133       */
134      protected OpenType(String className, String name, String desc)
135        throws OpenDataException
136      {
137        if (name == null || name.equals(""))
138          throw new IllegalArgumentException("The name can not be null " +
139                                             "or the empty string.");
140        if (desc == null || desc.equals(""))
141          throw new IllegalArgumentException("The description can not " +
142                                             "be null or the empty string.");
143        Class<?> type;
144        try
145          {
146            type = Class.forName(className);
147          }
148        catch (ClassNotFoundException e)
149          {
150            throw (OpenDataException) new OpenDataException("The class name, " + className +
151                                                            ", is unavailable.").initCause(e);
152          }
153        while (type.isArray())
154          type = type.getComponentType();
155        if (!(type.isPrimitive() || ALLOWED_CLASSNAMES_LIST.contains(type.getName())))
156          throw new OpenDataException("The class name, " + className +
157                                      ", does not specify a valid open type.");
158        this.className = className;
159        typeName = name;
160        description = desc;
161      }
162    
163      /**
164       * Performs an equality test on this object and the one specified.
165       *
166       * @param obj the object to test against this one.
167       * @return true if the two objects are equivalent.
168       * @see java.lang.Object#hashCode()
169       */
170      public abstract boolean equals(Object obj);
171    
172      /**
173       * Returns the name of the Java class this type represents.  This must
174       * be one of the {@link ALLOWED_CLASSNAMES} or an array of one of them.
175       * The specification of arrays follows the standard set by
176       * {@link java.lang.Class#getName()} i.e. the name is the class name
177       * preceded by n instances of '[' and an 'L', where n is number of
178       * dimensions used by the array.
179       *
180       * @return the class name.
181       */
182      public String getClassName()
183      {
184        return className;
185      }
186    
187      /**
188       * Returns a description of this open type.
189       *
190       * @return the description.
191       */
192      public String getDescription()
193      {
194        return description;
195      }
196    
197      /**
198       * Returns the name of this open type.
199       *
200       * @return the type name.
201       */
202      public String getTypeName()
203      {
204        return typeName;
205      }
206    
207      /**
208       * Returns a hash code for this open type.  The hash code
209       * should be consistent with the {@link equals()} method.
210       * Thus, it should continue to return the same value while
211       * the values used by the {@link equals()} method remain
212       * the same, and should return different hash codes for
213       * objects which are judged to be different using the
214       * {@link equals()} method.
215       *
216       * @return the hash code of this instance.
217       */
218      public abstract int hashCode();
219    
220      /**
221       * Returns true if this open type represents an array type.
222       *
223       * @return true if this open type represents an array type.
224       */
225      public boolean isArray()
226      {
227        return className.startsWith("[");
228      }
229    
230      /**
231       * Returns true if the specified object is a member of this
232       * type.
233       *
234       * @param obj the object to test for membership.
235       * @return true if the object is a member of this type.
236       */
237      public abstract boolean isValue(Object obj);
238    
239      /**
240       * Returns a textual representation of this type.
241       *
242       * @return a {@link java.lang.String} representation of this
243       *         type.
244       */
245      public abstract String toString();
246    
247    }