001    /* OpenMBeanConstructorInfoSupport.java -- Open typed info about an constructor.
002       Copyright (C) 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    package javax.management.openmbean;
039    
040    import java.util.Arrays;
041    
042    import javax.management.MBeanConstructorInfo;
043    import javax.management.MBeanParameterInfo;
044    
045    /**
046     * Describes a constructor for an open management bean.  
047     *
048     * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
049     * @since 1.5
050     */
051    public class OpenMBeanConstructorInfoSupport
052      extends MBeanConstructorInfo
053      implements OpenMBeanConstructorInfo
054    {
055    
056      /**
057       * Compatible with JDK 1.5
058       */
059      private static final long serialVersionUID = -4400441579007477003L;
060    
061      /**
062       * The hash code of this instance.
063       */
064      private transient Integer hashCode;
065    
066      /**
067       * The <code>toString()</code> result of this instance.
068       */
069      private transient String string;
070    
071      /**
072       * Constructs a @link{OpenMBeanConstructorInfo} with the specified
073       * name, description and parameter information. A <code>null</code>
074       * value for the parameter information is the same as passing in
075       * an empty array.  Neither the name nor the description may be
076       * null or equal to the empty string.  A copy of the parameter array
077       * is taken, so later changes have no effect.
078       *
079       * @param name the name of the constructor.
080       * @param desc a description of the constructor.
081       * @param sig the signature of the constructor, as a series
082       *            of {@link MBeanParameterInfo} objects, one for
083       *            each parameter.
084       * @throws IllegalArgumentException if the name or description is
085       *                                  either <code>null</code>
086       *                                  or the empty string.
087       * @throws ArrayStoreException if the members of the signature array
088       *                             are not assignable to
089       *                             {@link javax.management.MBeanParameterInfo}
090       */
091      public OpenMBeanConstructorInfoSupport(String name, String desc,
092                                             OpenMBeanParameterInfo[] sig)
093      {
094        super(name, desc, (MBeanParameterInfo[]) sig);
095        if (name == null)
096          throw new IllegalArgumentException("The name may not be null.");
097        if (desc == null)
098          throw new IllegalArgumentException("The description may not be null.");
099        if (name.length() == 0)
100          throw new IllegalArgumentException("The name may not be the empty string.");
101        if (desc.length() == 0)
102          throw new IllegalArgumentException("The description may not be the " +
103                                             "empty string.");
104      }
105    
106      /**
107       * Compares this attribute with the supplied object.  This returns
108       * true iff the object is an instance of {@link OpenMBeanConstructorInfo}
109       * with an equal name and signature.
110       *
111       * @param obj the object to compare.
112       * @return true if the object is a {@link OpenMBeanParameterInfo}
113       *         instance, 
114       *         <code>name.equals(object.getName())</code>,
115       *         and <code>signature.equals(object.getSignature())</code>.
116       */
117      public boolean equals(Object obj)
118      {
119        if (!(obj instanceof OpenMBeanConstructorInfo))
120          return false;
121        OpenMBeanConstructorInfo o = (OpenMBeanConstructorInfo) obj;
122        return getName().equals(o.getName()) &&
123          getSignature().equals(o.getSignature());
124      }
125    
126      /**
127       * <p>
128       * Returns the hashcode of the constructor information as the sum of
129       * the hashcodes of the name and signature (calculated by
130       * <code>java.util.Arrays.asList(signature).hashCode()</code>).
131       * </p>
132       * <p>
133       * As instances of this class are immutable, the return value
134       * is computed just once for each instance and reused
135       * throughout its life.
136       * </p>
137       *
138       * @return the hashcode of the constructor information.
139       */
140      public int hashCode()
141      {
142        if (hashCode == null)
143          hashCode = Integer.valueOf(getName().hashCode() + 
144                                     Arrays.asList(getSignature()).hashCode());
145        return hashCode.intValue();
146      }
147    
148      /**
149       * <p>
150       * Returns a textual representation of this instance.  This
151       * is constructed using the class name
152       * (<code>javax.management.openmbean.OpenMBeanConstructorInfo</code>)
153       * along with the name and signature.
154       * </p>
155       * <p>
156       * As instances of this class are immutable, the return value
157       * is computed just once for each instance and reused
158       * throughout its life.
159       * </p>
160       *
161       * @return a @link{java.lang.String} instance representing
162       *         the instance in textual form.
163       */
164      public String toString()
165      {
166        if (string == null)
167          string = getClass().getName()
168            + "[name=" + getName() 
169            + ",signature=" + Arrays.toString(getSignature())
170            + "]";
171        return string;
172      }
173    
174    }