org.apache.velocity.tools.generic
Class ExtendedListTool

java.lang.Object
  org.apache.velocity.tools.generic.ListTool
      org.apache.velocity.tools.generic.ExtendedListTool

public class ExtendedListTool

extends ListTool

Tool for working with Lists and arrays in Velocity templates. In addition to the features ListTool provides, it provides the function to retrieve the length, and create clones of a list or an array object. Also provides a method to convert arrays into Lists and Lists into arrays.

 Example uses:
  $primes                  -> new int[] {2, 3, 5, 7}
  $list.length($primes)    -> 4
  $list.get($primes, 2)    -> 5
  $list.clone($primes)     -> int[] {2, 3, 5, 7}, != $primes
  $list.set($primes, 2, 1) -> (primes[2] becomes 1)
  $list.get($primes, 2)    -> 1
  $list.get($clone, 2)     -> 5
 

 Example toolbox.xml config (if you want to use this with VelocityView):
 <tool>
   <key>list</key>
   <scope>application</scope>
   <class>org.apache.velocity.tools.generic.ExtendedListTool</class>
 </tool>
 

This tool is entirely threadsafe, and has no instance members. It may be used in any scope (request, session, or application).

Version:

$Id: ExtendedListTool.java,v 1.1 2005/08/31 14:39:34 czarneckid Exp $

Author:

Shinobu Kawai

Constructor Summary

ExtendedListTool()
Default constructor.

Method Summary

java.lang.Object	clone(java.lang.Object list) Gets the clone of a List/array.
java.lang.Integer	length(java.lang.Object array) Gets the length of an array/List.
java.lang.Object	toArray(java.lang.Object list) Converts a List object into an array.
java.util.List	toList(java.lang.Object array) Converts an array object into a List.

Methods inherited from class org.apache.velocity.tools.generic.ListTool

contains, get, isArray, isEmpty, isList, set, size

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ExtendedListTool

public ExtendedListTool()

Default constructor.

Method Detail

toList

public java.util.List toList(java.lang.Object array)

Converts an array object into a List.

• If the object is already a List, it will return the object itself.
• If the object is an array of an Object, it will return a List of the elements.
• If the object is an array of a primitive type, it will return a List of the elements wrapped in their wrapper class.
• If the object is none of the above, it will return null.

Parameters:

array - an array object.

Returns:

the converted java.util.List.

toArray

public java.lang.Object toArray(java.lang.Object list)

Converts a List object into an array.

• If the object is already an array, it will return the object itself.
• If the object is a List, it will return an array according to the object's toArray() method.
• If the object is none of the above, it will return null.

Parameters:

list - a List object.

Returns:

the converted array.

length

public java.lang.Integer length(java.lang.Object array)

Gets the length of an array/List. It will return null under the following conditions:

• array is null.
• array is not an array/List.

The result will be same as the ListTool.size(Object) method.

Parameters:

array - the array object.

Returns:

the length of the array.

See Also:

ListTool.size(Object)

clone

public java.lang.Object clone(java.lang.Object list)

Gets the clone of a List/array. It will return null under the following conditions:

• list is null.
• list is not a List/array.

Parameters:

list - the List/array object.

Returns:

the clone of the List/array.