Module org.wicketstuff.select2
Package org.wicketstuff.select2

Class ChoiceProvider<T>

java.lang.Object
org.wicketstuff.select2.ChoiceProvider<T>
Type Parameters:
T - type of choice object
All Implemented Interfaces:
Serializable, IDetachable, IClusterable
Direct Known Subclasses:
StringTextChoiceProvider
public abstract class ChoiceProvider<T> extends Object implements IDetachable

Acts as a bridge between Select2 components and the application's domain model.

The two important services provided by implementations are:

  • Feeding choices, represented by the application's domain objects, to Select2 components
  • Transcoding said choices to and from Json so they can consumed by Select2

For the most common usecase where each choice is rendered as a text string see StringTextChoiceProvider.

Author:
igor
See Also:

  • Constructor Summary

    Constructors
    Constructor
    Description
    ChoiceProvider()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    detach()
     
    abstract String
    getDisplayValue(T object)
    Get the value for displaying to an end user.
    abstract String
    getIdValue(T object)
    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.
    abstract void
    query(String term, int page, Response<T> response)
    Queries application for choices that match the search term and adds them to the response
    abstract Collection<T>
    toChoices(Collection<String> ids)
    Converts a list of choice ids back into application's choice objects.
    protected void
    toJson(T choice, com.github.openjson.JSONStringer stringer)
    Converts the specified choice to Json.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • ChoiceProvider

      public ChoiceProvider()

  • Method Details

    • getDisplayValue

      public abstract String getDisplayValue(T object)
      Get the value for displaying to an end user.
      Parameters:
      object - the actual object
      Returns:
      the value meant for displaying to an end user

    • getIdValue

      public abstract String getIdValue(T object)
      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.

      Note that the given index can be -1 if the object in question is not contained in the available choices.

      Parameters:
      object - The object for which the id should be generated
      Returns:
      String

    • query

      public abstract void query(String term, int page, Response<T> response)
      Queries application for choices that match the search term and adds them to the response
      Parameters:
      term - search term
      page - requested search term results page
      response - aggregate for matching choices as well as other response options

    • toJson

      protected void toJson(T choice, com.github.openjson.JSONStringer stringer) throws com.github.openjson.JSONException
      Converts the specified choice to Json.

      At the very least each choice should contain an id attribute. If no custom rendering function is specified, the text attribute should also be provided

      Example: If mapping a User {Long id, String name} using default rendering the code should look like this: 

       toJson(User choice, JSONWriter writer)
 {
        writer.key("id").value(choice.getId()).key("text").value(choice.getName());
 }

      Parameters:
      choice - choice to convert
      stringer - Json writer that should be used to covnert the choice
      Throws:
      com.github.openjson.JSONException

    • toChoices

      public abstract Collection<T> toChoices(Collection<String> ids)
      Converts a list of choice ids back into application's choice objects. When the choice provider is attached to a single-select component the ids collection will contain exactly one id, and a collection containing exactly one choice should be returned.
      Parameters:
      ids - collection containing choice ids
      Returns:
      collection containing application choice objects

    • detach

      public void detach()
      Specified by:
      detach in interface IDetachable