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    1   /*
    2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/SimpleVariableContext.java,v 1.16 2005/09/25 11:39:21 elharo Exp $
    3    * $Revision: 1.16 $
    4    * $Date: 2005/09/25 11:39:21 $
    5    *
    6    * ====================================================================
    7    *
    8    * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
    9    * All rights reserved.
    10   *
    11   * Redistribution and use in source and binary forms, with or without
    12   * modification, are permitted provided that the following conditions
    13   * are met:
    14   *
    15   * 1. Redistributions of source code must retain the above copyright
    16   *    notice, this list of conditions, and the following disclaimer.
    17   *
    18   * 2. Redistributions in binary form must reproduce the above copyright
    19   *    notice, this list of conditions, and the disclaimer that follows
    20   *    these conditions in the documentation and/or other materials
    21   *    provided with the distribution.
    22   *
    23   * 3. The name "Jaxen" must not be used to endorse or promote products
    24   *    derived from this software without prior written permission.  For
    25   *    written permission, please contact license@jaxen.org.
    26   *
    27   * 4. Products derived from this software may not be called "Jaxen", nor
    28   *    may "Jaxen" appear in their name, without prior written permission
    29   *    from the Jaxen Project Management (pm@jaxen.org).
    30   *
    31   * In addition, we request (but do not require) that you include in the
    32   * end-user documentation provided with the redistribution and/or in the
    33   * software itself an acknowledgement equivalent to the following:
    34   *     "This product includes software developed by the
    35   *      Jaxen Project <http://www.jaxen.org/>."
    36   * Alternatively, the acknowledgment may be graphical using the logos
    37   * available at http://www.jaxen.org/
    38   *
    39   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
    40   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    41   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    42   * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
    43   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    44   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    45   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
    46   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
    47   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    48   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
    49   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    50   * SUCH DAMAGE.
    51   *
    52   * ====================================================================
    53   * This software consists of voluntary contributions made by many
    54   * individuals on behalf of the Jaxen Project and was originally
    55   * created by bob mcwhirter <bob@werken.com> and
    56   * James Strachan <jstrachan@apache.org>.  For more information on the
    57   * Jaxen Project, please see <http://www.jaxen.org/>.
    58   *
    59   * $Id: SimpleVariableContext.java,v 1.16 2005/09/25 11:39:21 elharo Exp $
    60   */
    61
    62
    63  package org.jaxen;
    64
    65  import java.io.Serializable;
    66  import java.util.HashMap;
    67  import java.util.Map;
    68
    69  /*** Simple default implementation for <code>VariableContext</code>.
    70   *
    71   *  <p>
    72   *  This is a simple table-based key-lookup implementation
    73   *  for <code>VariableContext</code> which can be programmatically
    74   *  extended by setting additional variables.
    75   *  </p>
    76   *
    77   *  @author <a href="mailto:bob@werken.com">bob mcwhirter</a>
    78   */
    79  public class SimpleVariableContext implements VariableContext, Serializable
    80  {
    81      /*** Table of variable bindings. */
    82      private Map variables;
    83
    84      /*** Construct.
    85       *
    86       *  <p>
    87       *  Create a new empty variable context.
    88       *  </p>
    89       */
    90      public SimpleVariableContext()
    91      {
    92          variables = new HashMap();
    93      }
    94
    95      /*** Set the value associated with a variable.
    96       *
    97       *  <p>
    98       *  This method sets a variable that is
    99       *  associated with a particular namespace.
    100      *  These variables appear such as <code>$prefix:foo</code>
    101      *  in an XPath expression.  Prefix to URI resolution
    102      *  is the responsibility of a <code>NamespaceContext</code>.
    103      *  Variables within a <code>VariableContext</code> are
    104      *  referred to purely based upon their namespace URI,
    105      *  if any.
    106      *  </p>
    107      *
    108      *  @param namespaceURI the namespace URI of the variable
    109      *  @param localName the local name of the variable
    110      *  @param value The value to be bound to the variable
    111      */
    112     public void setVariableValue( String namespaceURI,
    113                                   String localName,
    114                                   Object value )
    115     {
    116         this.variables.put( new QualifiedName(namespaceURI, null, localName),
    117                             value );
    118     }
    119
    120     /*** Set the value associated with a variable.
    121      *
    122      *  <p>
    123      *  This method sets a variable that is <strong>not</strong>
    124      *  associated with any particular namespace.
    125      *  These variables look like <code>$foo</code>
    126      *  in an XPath expression.
    127      *  </p>
    128      *
    129      *  @param localName the local name of the variable
    130      *  @param value the value to be bound to the variable
    131      */
    132     public void setVariableValue( String localName,
    133                                   Object value )
    134     {
    135         this.variables.put( new QualifiedName(null, null, localName), value );
    136     }
    137
    138     public Object getVariableValue( String namespaceURI,
    139                                     String prefix,
    140                                     String localName )
    141         throws UnresolvableException
    142     {
    143         QualifiedName key = new QualifiedName( namespaceURI, prefix, localName );
    144
    145         if ( this.variables.containsKey(key) )
    146         {
    147             return this.variables.get( key );
    148         }
    149         else
    150         {
    151             throw new UnresolvableException( "Variable " + key.getClarkForm() );
    152         }
    153     }
    154 }