001    /* RefAddr.java -- Abstract superclass of addresses used in References
002       Copyright (C) 2000, 2001 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.naming;
039    
040    import java.io.Serializable;
041    
042    /**
043     * Abstract superclass of addresses used in References.
044     * A <code>Reference</code> object contains a <code>Vector</code> of
045     * <code>RefAddr</code>s which are used to reference/address the object.
046     * This abstract superclass keeps track of the type of address, which will be
047     * returned by <code>getType()</code>. And defines a abstract method
048     * <code>getContent()</code> which must be implemented in concrete subclasses
049     * such as <code>BinaryRefAddr</code> and <code>StringRefAddr</code>.
050     *
051     * @see Reference
052     * @see BinaryRefAddr
053     * @see StringRefAddr
054     * @since 1.3
055     * @author Anthony Green (green@redhat.com)
056     * @author Mark Wielaard (mark@klomp.org)
057     */
058    public abstract class RefAddr implements Serializable
059    {
060      /**
061       * The string resprenstation of the type of address.
062       * Set by the constructor and returned by the getType() method.
063       */
064      protected String addrType;
065    
066      /**
067       * Protected constructor for use by subclasses.
068       * Sets the addrType field of this object to the supplied String.
069       *
070       * @exception NullPointerException if the supplied String is null.
071       */
072      protected RefAddr(String addrType)
073      {
074            if (addrType == null)
075              throw new NullPointerException("addrType cannot be null");
076    
077        this.addrType = addrType;
078      }
079    
080      /**
081       * Returns the non-null address type given to the constructor.
082       */
083      public String getType()
084      {
085        return addrType;
086      }
087    
088      /**
089       * Returns the possibly null content of this RefAddr.
090       * The actual value is defined by the non-abstract subclass.
091       */
092      public abstract Object getContent();
093    
094      /**
095       * Checks if the object is a RefAddr with the same type and content.
096       *
097       * @return true if the given object is an instance of RefAddr, the addrType
098       *         is the same as this addrType and the content is equals to the
099       *         content of this object.
100       */
101      public boolean equals(Object o)
102      {
103        if (o instanceof RefAddr)
104          {
105            RefAddr refAddr = (RefAddr) o;
106            if (this.getType().equals(refAddr.getType()))
107            {
108              Object c1 = this.getContent();
109              Object c2 = refAddr.getContent();
110              if (c1 == null)
111                return c2 == null;
112              else
113                return c1.equals(c2);
114            }
115          }
116        return false;
117      }
118    
119      /**
120       * Returns the hashCode which is the hasCode of the String returned by
121       * <code>getType()</code> plus the hashCode of the Object returned by
122       * <code>getContent</code> (when not null).
123       */
124      public int hashCode()
125      {
126        int result = getType().hashCode();
127        Object o = getContent();
128        if (o != null)
129          result += o.hashCode();
130    
131        return result;
132      }
133    
134      /**
135       * Returns a String representation of the RefAddr.
136       * Should only be used for debugging purposes.
137       */
138      public String toString()
139      {
140        return "[RefAddr type: " + getType() + " content: " + getContent() + ']';
141      }
142    }