cvs commit: jakarta-commons/digester/src/java/org/apache/commons/digester/substitution VariableAttributes.java

[rd...@apache.org]

rdonkin     2003/12/02 15:22:12

  Added:       digester/src/java/org/apache/commons/digester/substitution
                        VariableAttributes.java
  Log:
  Added support for substitution of variables (and anything else that people want ;). This is a first cut, hopefully I'll be back with more documentation and Remy's peculiar implementation tommorrow. Contains contributions by Simon Kitching.
  
  Revision  Changes    Path
  1.1                  jakarta-commons/digester/src/java/org/apache/commons/digester/substitution/VariableAttributes.java
  
  Index: VariableAttributes.java
  ===================================================================
  /*
   * $Header: /home/cvs/jakarta-commons/digester/src/java/org/apache/commons/digester/substitution/VariableAttributes.java,v 1.1 2003/12/02 23:22:11 rdonkin Exp $
   * $Revision: 1.1 $
   * $Date: 2003/12/02 23:22:11 $
   *
   * ====================================================================
   * 
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 2001-2003 The Apache Software Foundation.  All rights
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer. 
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution,
   *    if any, must include the following acknowledgement:  
   *       "This product includes software developed by the 
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowledgement may appear in the software itself,
   *    if and wherever such third-party acknowledgements normally appear.
   *
   * 4. The names "Apache", "The Jakarta Project", "Commons", and "Apache Software
   *    Foundation" must not be used to endorse or promote products derived
   *    from this software without prior written permission. For written 
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache",
   *    "Apache" nor may "Apache" appear in their names without prior 
   *    written permission of the Apache Software Foundation.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */ 
  
  
  package org.apache.commons.digester.substitution;
  
  import org.xml.sax.Attributes;
  
  import java.util.Map;
  import java.util.ArrayList;
  
  
  /**
   * <p>Wrapper for an org.xml.sax.Attributes object which expands any 
   * "variables" referenced in the attribute value via ${foo} or similar. 
   * This is only done something actually asks for the attribute value, 
   * thereby imposing no performance penalty if the attribute is not used.</p>
   *
   * @author Simon Kitching
   * @version $Revision: 1.1 $ $Date: 2003/12/02 23:22:11 $
   */
  
  public class VariableAttributes implements Attributes {
  
      // list of mapped attributes.
      private ArrayList values = new ArrayList(10);
  
      private Attributes attrs;
      private VariableExpander expander;
      
      // ------------------- Public Methods
      
      /**
       * Specify which attributes class this object is a proxy for.
       */
      public void init(Attributes attrs, VariableExpander expander) {
          this.attrs = attrs;
          this.expander = expander;
  
          // I hope this doesn't release the memory for this array; for 
          // efficiency, this should just mark the array as being size 0.
          values.clear(); 
      }
  
      public String getValue(int index) {
          if (index >= values.size()) {
              // Expand the values array with null elements, so the later
              // call to set(index, s) works ok.
              //
              // Unfortunately, there is no easy way to set the size of
              // an arraylist; we must repeatedly add null elements to it..
              values.ensureCapacity(index+1);
              for(int i = values.size(); i<= index; ++i) {
                  values.add(null);
              }
          }
          
          String s = (String) values.get(index);
          
          if (s == null) {
              // we have never been asked for this value before.
              // get the real attribute value and perform substitution
              // on it.
              s = attrs.getValue(index);
              if (s != null) {
                  s = expander.expand(s);
                  values.set(index, s);
              }
          }
          
          return s;
      }
      
      public String getValue(String qname) {
          int index = attrs.getIndex(qname);
          if (index == -1) {
              return null;
          }
          return getValue(index);
      }
      
      public String getValue(String uri, String localname) {
          int index = attrs.getIndex(uri, localname);
          if (index == -1) {
              return null;
          }
          return getValue(index);
      }
      
      // plain proxy methods follow : nothing interesting :-)
      public int getIndex(String qname) {
          return attrs.getIndex(qname); 
      }
      
      public int getIndex(String uri, String localpart) {
          return attrs.getIndex(uri, localpart); 
      }
      
      public int getLength() {
          return attrs.getLength();
      }
      
      public String getLocalName(int index) {
          return attrs.getLocalName(index);
      }
      
      public String getQName(int index) {
          return attrs.getQName(index);
      }
      
      public String getType(int index) {
          return attrs.getType(index);
      }
  
      public String getType(String qname) {
          return attrs.getType(qname);
      }
      
      public String getType(String uri, String localname) {
          return attrs.getType(uri, localname);
      }
      
      public String getURI(int index) {
          return attrs.getURI(index);
      }
   
  }
  
  
  

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