001/* RefAddr.java -- Abstract superclass of addresses used in References
002   Copyright (C) 2000, 2001 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.naming;
039
040import 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 */
058public 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}