@DefaultKey(value="sorter") public class SortTool extends Object
The sort tool is specifically designed to use within a #foreach but you may find other uses for it.
The sort tool can handle all of the collection types supported by #foreach and the same constraints apply as well as the following. Every object in the collection must support the set of properties selected to sort on. Each property which is to be sorted on must return one of the follow:
During the sort operation all properties are compared by calling compareTo() with the exception of Strings for which compareToIgnoreCase() is called.
The sort is performed by calling Collections.sort() after marshalling the collection to sort into an appropriate collection type. The original collection will not be re-ordered; a new list containing the sorted elements will always be returned.
The tool is used as follows:
Single Property Sort #foreach($obj in $sorter.sort($objects, "name")) $obj.name Ordinal= $obj.ordinal #end End Multiple Property Sort #foreach($obj in $sorter.sort($objects, ["name", "ordinal"])) $obj.name, $obj.ordinal #end EndThe sort method takes two parameters a collection and a property name or an array of property names. The property names and corresponding methods must conform to java bean standards since commons-beanutils is used to extract the property values.
By default the sort tool sorts ascending, you can override this by adding a sort type suffix to any property name.
The supported suffixes are:
For ascending :asc For descending :desc Example #foreach($obj in $sorter.sort($objects, ["name:asc", "ordinal:desc"])) $obj.name, $obj.ordinal #end
This will sort first by Name in ascending order and then by Ordinal in descending order, of course you could have left the :asc off of the 'Name' property as ascending is always the default.
Example tools.xml config (if you want to use this with VelocityView): <tools> <toolbox scope="application"> <tool class="org.apache.velocity.tools.generic.SortTool"/> </toolbox> </tools>
Modifier and Type | Class and Description |
---|---|
static class |
SortTool.PropertiesComparator
Does all of the comparisons
|
Constructor and Description |
---|
SortTool() |
Modifier and Type | Method and Description |
---|---|
protected static Comparable |
getComparable(Object object,
String property)
Safely retrieves the comparable value for the specified property
from the specified object.
|
protected Collection |
internalSort(List list,
List properties) |
Collection |
sort(Collection collection) |
Collection |
sort(Collection collection,
List properties) |
Collection |
sort(Map map) |
Collection |
sort(Map map,
List properties) |
Collection |
sort(Object[] array) |
Collection |
sort(Object[] array,
List properties) |
Collection |
sort(Object object,
String property)
Sorts the collection on a single property.
|
public Collection sort(Collection collection)
public Collection sort(Object[] array)
public Collection sort(Map map)
public Collection sort(Object object, String property)
object
- the collection to be sorted.property
- the property to sort on.public Collection sort(Collection collection, List properties)
public Collection sort(Map map, List properties)
public Collection sort(Object[] array, List properties)
protected Collection internalSort(List list, List properties)
protected static Comparable getComparable(Object object, String property)
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