[Jakarta-velocity Wiki] Update of "ListTool" by NathanBubna

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The following page has been changed by NathanBubna:
http://wiki.apache.org/jakarta-velocity/ListTool

The comment on the change is:
ListTool is now in SVN

------------------------------------------------------------------------------
   * clone support
   * length support (same as size)
  
+ The ListTool is now kept in the [http://svn.apache.org/viewcvs.cgi/jakarta/velocity/tools/trunk/src/java/org/apache/velocity/tools/generic/ListTool.java?view=markup SVN repo]!  The ExtendedListTool is still below for those interested in it. :)
- {{{
- /*
-  * Copyright 2003-2005 The Apache Software Foundation.
-  *
-  * Licensed under the Apache License, Version 2.0 (the "License");
-  * you may not use this file except in compliance with the License.
-  * You may obtain a copy of the License at
-  *
-  *     http://www.apache.org/licenses/LICENSE-2.0
-  *
-  * Unless required by applicable law or agreed to in writing, software
-  * distributed under the License is distributed on an "AS IS" BASIS,
-  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  * See the License for the specific language governing permissions and
-  * limitations under the License.
-  */
- 
- package org.apache.velocity.tools.generic;
- 
- import java.lang.reflect.Array;
- import java.util.List;
- 
- /**
-  * Tool for working with Lists and arrays in Velocity templates.
-  * It provides a method to get and set specified elements.
-  * Also provides methods to perform the following actions to Lists and arrays:
-  * <ul>
-  *   <li>Check if it is empty.</li>
-  *   <li>Check if it contains a certain element.</li>
-  * </ul>
-  *
-  * <p><pre>
-  * Example uses:
-  *  $primes                    -> new int[] {2, 3, 5, 7}
-  *  $list.size($primes)        -> 4
-  *  $list.get($primes, 2)      -> 5
-  *  $list.set($primes, 2, 1)   -> (primes[2] becomes 1)
-  *  $list.get($primes, 2)      -> 1
-  *  $list.isEmpty($primes)     -> false
-  *  $list.contains($primes, 7) -> true
-  *
-  * Example toolbox.xml config (if you want to use this with VelocityView):
-  * &lt;tool&gt;
-  *   &lt;key&gt;list&lt;/key&gt;
-  *   &lt;scope&gt;application&lt;/scope&gt;
-  *   &lt;class&gt;org.apache.velocity.tools.generic.ListTool&lt;/class&gt;
-  * &lt;/tool&gt;
-  * </pre></p>
-  *
-  * <p>This tool is entirely threadsafe, and has no instance members.
-  * It may be used in any scope (request, session, or application).
-  * </p>
-  *
-  * @author <a href="mailto:shinobu@ieee.org">Shinobu Kawai</a>
-  * @version $Id: $
-  */
- public class ListTool
- {
- 
-     /**
-      * Default constructor.
-      */
-     public ListTool()
-     {
-     }
- 
-     /**
-      * Gets the specified element of a List/array.
-      * It will return null under the following conditions:
-      * <ul>
-      *   <li><code>list</code> is null.</li>
-      *   <li><code>list</code> is not a List/array.</li>
-      *   <li><code>list</code> doesn't have an <code>index</code>th value.</li>
-      * </ul>
-      * @param list the List/array object.
-      * @param index the index of the List/array to get.
-      * @return the specified element of the List/array.
-      */
-     public Object get(Object list, int index)
-     {
-         if (this.isArray(list))
-         {
-             return this.getFromArray(list, index);
-         }
-         if (!this.isList(list))
-         {
-             return null;
-         }
- 
-         try
-         {
-             return ((List) list).get(index);
-         }
-         catch (IndexOutOfBoundsException e)
-         {
-             // The index was wrong.
-             return null;
-         }
-     }
- 
-     /**
-      * Gets the specified element of an array.
-      * @param array the array object.
-      * @param index the index of the array to get.
-      * @return the specified element of the array.
-      */
-     private Object getFromArray(Object array, int index)
-     {
-         try
-         {
-             return Array.get(array, index);
-         }
-         catch (IndexOutOfBoundsException e)
-         {
-             // The index was wrong.
-             return null;
-         }
-     }
- 
-     /**
-      * Sets the specified element of a List/array.
-      * It will return null under the following conditions:
-      * <ul>
-      *   <li><code>list</code> is null.</li>
-      *   <li><code>list</code> is not a List/array.</li>
-      *   <li><code>list</code> doesn't have an <code>index</code>th value.</li>
-      * </ul>
-      * @param list the List/array object.
-      * @param index the index of the List/array to set.
-      * @param value the element to set.
-      * @return blank if set, null if not set.
-      */
-     public Object set(Object list, int index, Object value)
-     {
-         if (this.isArray(list))
-         {
-             return this.setToArray(list, index, value);
-         }
-         if (!this.isList(list))
-         {
-             return null;
-         }
- 
-         try
-         {
-             ((List) list).set(index, value);
-             return "";
-         }
-         catch (IndexOutOfBoundsException e)
-         {
-             // The index was wrong.
-             return null;
-         }
-     }
- 
-     /**
-      * Sets the specified element of an array.
-      * @param array the array object.
-      * @param index the index of the array to set.
-      * @param value the element to set.
-      * @return blank if set, null if not set.
-      */
-     private Object setToArray(Object array, int index, Object value)
-     {
-         try
-         {
-             Array.set(array, index, value);
-             return "";
-         }
-         catch (IndexOutOfBoundsException e)
-         {
-             // The index was wrong.
-             return null;
-         }
-     }
- 
-     /**
-      * Gets the size of a List/array.
-      * It will return null under the following conditions:
-      * <ul>
-      *   <li><code>list</code> is null.</li>
-      *   <li><code>list</code> is not a List/array.</li>
-      * </ul>
-      * The result will be same as the {@link #length(Object)} method.
-      * @param list the List object.
-      * @return the size of the List.
-      * @see #length(Object)
-      */
-     public Integer size(Object list)
-     {
-         if (this.isArray(list))
-         {
-             // Thanks to Eric Fixler for this refactor.
-             return new Integer(Array.getLength(list));
-         }
-         if (!this.isList(list))
-         {
-             return null;
-         }
- 
-         return new Integer(((List) list).size());
-     }
- 
-     /**
-      * Checks if an object is an array.
-      * @param object the object to check.
-      * @return <code>true</code> if the object is an array.
-      */
-     public boolean isArray(Object object)
-     {
-         if (object == null)
-         {
-             return false;
-         }
-         return object.getClass().isArray();
-     }
- 
-     /**
-      * Checks if an object is a List.
-      * @param object the object to check.
-      * @return <code>true</code> if the object is a List.
-      */
-     public boolean isList(Object object)
-     {
-         return object instanceof List;
-     }
- 
-     /**
-      * Checks if a List/array is empty.
-      * @param list the List/array to check.
-      * @return <code>true</code> if the List/array is empty.
-      */
-     public Boolean isEmpty(Object list)
-     {
-         Integer size = this.size(list);
-         if (size == null)
-         {
-             return null;
-         }
- 
-         return new Boolean(size.intValue() == 0);
-     }
- 
-     /**
-      * Checks if a List/array contains a certain element.
-      * @param list the List/array to check.
-      * @param element the element to check.
-      * @return <code>true</code> if the List/array contains the element.
-      */
-     public Boolean contains(Object list, Object element)
-     {
-         if (this.isArray(list))
-         {
-             return this.arrayContains(list, element);
-         }
-         if (!this.isList(list))
-         {
-             return null;
-         }
- 
-         return new Boolean(((List) list).contains(element));
-     }
- 
-     /**
-      * Checks if an array contains a certain element.
-      * @param array the array to check.
-      * @param element the element to check.
-      * @return <code>true</code> if the array contains the element.
-      */
-     private Boolean arrayContains(Object array, Object element)
-     {
-         int size = this.size(array).intValue();
- 
-         for (int index = 0; index < size; ++index)
-         {
-             if (this.equals(element, this.getFromArray(array, index)))
-             {
-                 return Boolean.TRUE;
-             }
-         }
-         return Boolean.FALSE;
-     }
- 
-     /**
-      * Check if two objects are equal.
-      * @param what an object
-      * @param with another object.
-      * @return <code>true</code> if the two objects are equal.
-      */
-     private boolean equals(Object what, Object with)
-     {
-         if (what == null)
-         {
-             return with == null;
-         }
- 
-         return what.equals(with);
-     }
- 
- }
- }}}
  
  {{{
  /*

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