wicket.markup.html.form
Class ChoiceRenderer

java.lang.Object
  wicket.markup.html.form.ChoiceRenderer

All Implemented Interfaces:

IChoiceRenderer, java.io.Serializable

public class ChoiceRenderer

extends java.lang.Object

implements IChoiceRenderer

Default implementation of IChoiceRenderer. Usage:

new DropDownChoice("users",new Model(selectedUser),listOfUsers)

creates a DropDownChoice of users and the display value will be toString() and the id the index of the object in the ListOfUsers.

new DropDownChoice("users",new Model(selectedUser),listOfUsers,new ChoiceRenderer("name"))

creates a DropDownChoice of users and the display value will be looked up by ognl ("name") and the id the index of the object in the ListOfUsers

new DropDownChoice("users",new Model(selectedUser),listOfUsers,new ChoiceRenderer("name","id"))

creates a DropDownChoice of users and the display value will be looked up by ognl ("name") and the id will be looked up by the ognl expression "id"

Author:

jcompagner

See Also:

Serialized Form

Constructor Summary

ChoiceRenderer()
Construct.

ChoiceRenderer(java.lang.String displayExpression)
Construct.

ChoiceRenderer(java.lang.String displayExpression, java.lang.String idExpression)
Construct.

Method Summary

java.lang.String	getDisplayValue(java.lang.Object object) Get the value for displaying to an end user.
java.lang.String	getIdValue(java.lang.Object object, int index) This method is called to get the id value of an object (used as the value attribute of a choice element) The id can be extracted from the object like a primary key, or if the list is stable you could just return a toString of the index.

Methods inherited from class java.lang.Object

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

Constructor Detail

ChoiceRenderer

public ChoiceRenderer()

Construct. When you use this constructor, the display value will be determined by calling toString() on the list object, and the id will be based on the list index. the id value will be the index

ChoiceRenderer

public ChoiceRenderer(java.lang.String displayExpression)

Construct. When you use this constructor, the display value will be determined by executing the given ognl expression on the list object, and the id will be based on the list index. The display value will be calculated by the given ognl expression

Parameters:

displayExpression - An ognl expression to get the display value

ChoiceRenderer

public ChoiceRenderer(java.lang.String displayExpression,
                      java.lang.String idExpression)

Construct. When you use this constructor, both the id and the display value will be determined by executing the given ognl expressions on the list object.

Parameters:

displayExpression - An ognl expression to get the display value

idExpression - An ognl expression to get the id value

Method Detail

getDisplayValue

public java.lang.String getDisplayValue(java.lang.Object object)

Description copied from interface: IChoiceRenderer

Get the value for displaying to an end user.

Specified by:

getDisplayValue in interface IChoiceRenderer

Parameters:

object - the actual object

Returns:

the value meant for displaying to an end user

See Also:

IChoiceRenderer.getDisplayValue(java.lang.Object)

getIdValue

public java.lang.String getIdValue(java.lang.Object object,
                                   int index)

Description copied from interface: IChoiceRenderer

This method is called to get the id value of an object (used as the value attribute of a choice element) The id can be extracted from the object like a primary key, or if the list is stable you could just return a toString of the index.

Specified by:

getIdValue in interface IChoiceRenderer

Parameters:

object - The object for which the id should be generated

index - The index of the object in the choices list.

Returns:

String

See Also:

IChoiceRenderer.getIdValue(java.lang.Object, int)