wicket.markup.html.form
Class DropDownChoice

java.lang.Object
  wicket.Component
      wicket.MarkupContainer
          wicket.markup.html.WebMarkupContainer
              wicket.markup.html.form.FormComponent
                  wicket.markup.html.form.DropDownChoice

All Implemented Interfaces:

java.io.Serializable, IRequestListener, IOnChangeListener

Direct Known Subclasses:

ListChoice

public class DropDownChoice
extends FormComponent
implements IOnChangeListener

A choice implemented as a dropdown menu/list.

Java:

 List SITES = Arrays.asList(new String[] { "The Server Side", "Java Lobby", "Java.Net" });
 
 // Add a dropdown choice component that uses Input's 'site' property to designate the
 // current selection, and that uses the SITES list for the available options.
 // Note that when the selection is null, Wicket will lookup a localized string to
 // represent this null with key: "id + '.null'". In this case, this is 'site.null'
 // which can be found in DropDownChoicePage.properties
 form.add(new DropDownChoice("site", SITES));
 

HTML:

        <select wicket:id="site">
                <option>site 1</option>
                <option>site 2</option>
        </select>
 

You can can extend this class and override method wantOnSelectionChangedNotifications() to force server roundtrips on each selection change.

Author:

Jonathan Locke, Eelco Hillenius, Johan Compagner

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class wicket.markup.html.form.FormComponent

FormComponent.IVisitor

Nested classes/interfaces inherited from class wicket.Component

Component.ComponentModelChange, Component.EnabledChange, Component.VisibilityChange

Field Summary

Fields inherited from class wicket.markup.html.form.FormComponent

FLAG_CONVERT_EMPTY_INPUT_STRING_TO_NULL, VALUE_SEPARATOR

Fields inherited from class wicket.Component

ENABLE, FLAG_RESERVED1, FLAG_RESERVED2, FLAG_RESERVED3, FLAG_RESERVED4, FLAG_RESERVED5, FLAG_RESERVED6, FLAG_RESERVED7, FLAG_RESERVED8, PATH_SEPARATOR, RENDER

Fields inherited from interface wicket.markup.html.form.IOnChangeListener

INTERFACE

Constructor Summary

DropDownChoice(java.lang.String id)

DropDownChoice(java.lang.String id, IModel choices)

DropDownChoice(java.lang.String id, IModel choices, IChoiceRenderer renderer)

DropDownChoice(java.lang.String id, IModel model, IModel choices)

DropDownChoice(java.lang.String id, IModel model, IModel choices, IChoiceRenderer renderer)

DropDownChoice(java.lang.String id, IModel model, java.util.List choices)

DropDownChoice(java.lang.String id, IModel model, java.util.List data, IChoiceRenderer renderer)

DropDownChoice(java.lang.String id, java.util.List choices)

DropDownChoice(java.lang.String id, java.util.List data, IChoiceRenderer renderer)

Method Summary

protected void	appendOptionHtml(AppendingStringBuffer buffer, java.lang.Object choice, int index, java.lang.String selected) Generats and appends html for a single choice into the provided buffer
protected java.lang.Object	convertValue(java.lang.String[] value) Subclasses should overwrite this if the conversion is not done through the type field and the IConverter.
protected void	detachModel() Detaches the model for this component if it is detachable.
IChoiceRenderer	getChoiceRenderer()
java.util.List	getChoices()
protected java.lang.CharSequence	getDefaultChoice(java.lang.Object selected) The localizer will be ask for the property to display Depending on if null is allowed or not it will ask for: nullValid: when null is valid and by default it will show an empty string as a choice. null: when null is not a valid choice and it will make a choice with "Choose One" The choice for null is valid will always be returned.
java.lang.String	getModelValue()
boolean	isNullValid() Is the null value a valid value?
protected boolean	isSelected(java.lang.Object object, int index, java.lang.String selected) Gets whether the given value represents the current selection.
protected boolean	localizeDisplayValues() Override this method if you want to localize the display values of the generated options.
protected void	onComponentTag(ComponentTag tag) Processes the component tag.
protected void	onComponentTagBody(MarkupStream markupStream, ComponentTag openTag) Handle the container's body.
void	onSelectionChanged() Called when a selection changes.
protected void	onSelectionChanged(java.lang.Object newSelection) Template method that can be overriden by clients that implement IOnChangeListener to be notified by onChange events of a select element.
void	setChoiceRenderer(IChoiceRenderer renderer) Set the choice renderer to be used.
void	setChoices(IModel choices) Sets the list of choices
void	setChoices(java.util.List choices) Sets the list of choices.
void	setNullValid(boolean nullValid) Is the null value a valid value?
protected boolean	supportsPersistence()
protected boolean	wantOnSelectionChangedNotifications() Whether this component's onSelectionChanged event handler should called using javascript if the selection changes.

Methods inherited from class wicket.markup.html.form.FormComponent

add, checkRequired, clearInput, convert, error, getConvertedInput, getForm, getInput, getInputAsArray, getInputName, getLabel, getRawInput, getType, getValidatorKeyPrefix, getValidators, getValue, hasRawInput, inputAsInt, inputAsInt, inputAsIntArray, inputAsStringArray, inputChanged, internalOnModelChanged, invalid, isInputNullable, isMultiPart, isPersistent, isRequired, isValid, isValidated, onDetach, onDisabled, onInvalid, onValid, processInput, setLabel, setModelValue, setModelValue, setPersistent, setRequired, setType, updateModel, valid, validate, validateRequired, validateValidators

Methods inherited from class wicket.markup.html.WebMarkupContainer

getMarkupType, getWebPage

Methods inherited from class wicket.MarkupContainer

add, autoAdd, contains, findMarkupStream, get, getAssociatedMarkupStream, getMarkupStream, internalAdd, internalAttach, internalDetach, isTransparentResolver, iterator, iterator, newMarkupResourceStream, onRender, remove, remove, removeAll, renderAll, renderAssociatedMarkup, renderComponentTagBody, replace, setMarkupStream, setModel, size, toString, toString, visitChildren, visitChildren

Methods inherited from class wicket.Component

add, addStateChange, checkComponentTag, checkComponentTagAttribute, continueToOriginalDestination, debug, detachBehaviors, detachModels, error, exceptionMessage, fatal, findPage, findParent, findParentWithAssociatedMarkup, getApplication, getApplicationPages, getApplicationSettings, getBehaviors, getBehaviors, getClassRelativePath, getConverter, getEscapeModelStrings, getFeedbackMessage, getFlag, getFlag, getId, getLocale, getLocalizer, getMarkupAttributes, getMarkupId, getMetaData, getModel, getModelComparator, getModelObject, getModelObjectAsString, getOutputMarkupId, getPage, getPageFactory, getPageRelativePath, getParent, getPath, getRenderBodyOnly, getRequest, getRequestCycle, getResponse, getSession, getSizeInBytes, getString, getString, getString, getStyle, getVariation, hasErrorMessage, hasFeedbackMessage, info, initModel, internalOnAttach, internalOnDetach, isActionAuthorized, isAncestorOf, isBehaviorAccepted, isEnableAllowed, isEnabled, isHeadRendered, isIgnoreAttributeModifier, isRenderAllowed, isVersioned, isVisible, isVisibleInHierarchy, modelChanged, modelChanging, newPage, newPage, onAfterRender, onAttach, onBeforeRender, onBeginRequest, onEndRequest, onModelChanged, onModelChanging, onRender, redirectToInterceptPage, remove, render, render, renderComponent, renderComponent, renderComponentTag, rendered, renderedBehaviors, renderHead, replaceComponentTagBody, replaceWith, resetHeadRendered, sameRootModel, sameRootModel, setAuto, setEnabled, setEscapeModelStrings, setFlag, setFlag, setIgnoreAttributeModifier, setMetaData, setModelObject, setOutputMarkupId, setRedirect, setRenderBodyOnly, setResponsePage, setResponsePage, setResponsePage, setVersioned, setVisible, urlFor, urlFor, urlFor, urlFor, urlFor, visitParents, warn

Methods inherited from class java.lang.Object

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

Constructor Detail

DropDownChoice

public DropDownChoice(java.lang.String id)

See Also:

AbstractChoice.AbstractChoice(String)

DropDownChoice

public DropDownChoice(java.lang.String id,
                      java.util.List choices)

See Also:

AbstractChoice.AbstractChoice(String, List)

DropDownChoice

public DropDownChoice(java.lang.String id,
                      java.util.List data,
                      IChoiceRenderer renderer)

See Also:

AbstractChoice.AbstractChoice(String, List,IChoiceRenderer)

DropDownChoice

public DropDownChoice(java.lang.String id,
                      IModel model,
                      java.util.List choices)

See Also:

AbstractChoice.AbstractChoice(String, IModel, List)

DropDownChoice

public DropDownChoice(java.lang.String id,
                      IModel model,
                      java.util.List data,
                      IChoiceRenderer renderer)

See Also:

AbstractChoice.AbstractChoice(String, IModel, List, IChoiceRenderer)

DropDownChoice

public DropDownChoice(java.lang.String id,
                      IModel choices)

See Also:

AbstractChoice.AbstractChoice(String, IModel)

DropDownChoice

public DropDownChoice(java.lang.String id,
                      IModel model,
                      IModel choices)

See Also:

AbstractChoice.AbstractChoice(String, IModel,IModel)

DropDownChoice

public DropDownChoice(java.lang.String id,
                      IModel choices,
                      IChoiceRenderer renderer)

See Also:

AbstractChoice.AbstractChoice(String, IModel,IChoiceRenderer)

DropDownChoice

public DropDownChoice(java.lang.String id,
                      IModel model,
                      IModel choices,
                      IChoiceRenderer renderer)

See Also:

AbstractChoice.AbstractChoice(String, IModel, IModel,IChoiceRenderer)

Method Detail

onSelectionChanged

public final void onSelectionChanged()

Called when a selection changes.

Specified by:

onSelectionChanged in interface IOnChangeListener

onComponentTag

protected void onComponentTag(ComponentTag tag)

Processes the component tag.

Overrides:

onComponentTag in class FormComponent

Parameters:

tag - Tag to modify

See Also:

Component.onComponentTag(wicket.markup.ComponentTag)

onSelectionChanged

protected void onSelectionChanged(java.lang.Object newSelection)

Template method that can be overriden by clients that implement IOnChangeListener to be notified by onChange events of a select element. This method does nothing by default.

Called when a option is selected of a dropdown list that wants to be notified of this event. This method is to be implemented by clients that want to be notified of selection events.

Parameters:

newSelection - The newly selected object of the backing model NOTE this is the same as you would get by calling getModelObject() if the new selection were current

wantOnSelectionChangedNotifications

protected boolean wantOnSelectionChangedNotifications()

Whether this component's onSelectionChanged event handler should called using javascript if the selection changes. If true, a roundtrip will be generated with each selection change, resulting in the model being updated (of just this component) and onSelectionChanged being called. This method returns false by default.

Returns:

True if this component's onSelectionChanged event handler should called using javascript if the selection changes

getModelValue

public final java.lang.String getModelValue()

Overrides:

getModelValue in class FormComponent

Returns:

Value to return when model value is needed

See Also:

FormComponent.getModelValue()

isNullValid

public boolean isNullValid()

Is the null value a valid value?

Returns:

true when the null value is allowed.

setNullValid

public void setNullValid(boolean nullValid)

Is the null value a valid value?

Parameters:

nullValid - whether null is a valid value

convertValue

protected final java.lang.Object convertValue(java.lang.String[] value)

Description copied from class: FormComponent

Subclasses should overwrite this if the conversion is not done through the type field and the IConverter. WARNING: this method may be removed in future versions. If conversion fails then a ConversionException should be thrown

Overrides:

convertValue in class FormComponent

Parameters:

value - The value can be the getInput() or through a cookie

Returns:

The converted value. default returns just the given value

See Also:

FormComponent.convertValue(String[])

getDefaultChoice

protected java.lang.CharSequence getDefaultChoice(java.lang.Object selected)

The localizer will be ask for the property to display Depending on if null is allowed or not it will ask for:

• nullValid: when null is valid and by default it will show an empty string as a choice.
• null: when null is not a valid choice and it will make a choice with "Choose One"

The choice for null is valid will always be returned. The choice when null is not valid will only be returned if the selected object is null.

Parameters:

selected - The object that's currently selected

Returns:

Any default choice, such as "Choose One", depending on the subclass

See Also:

AbstractChoice.getDefaultChoice(Object)

isSelected

protected boolean isSelected(java.lang.Object object,
                             int index,
                             java.lang.String selected)

Gets whether the given value represents the current selection.

Parameters:

object - The object to check

index - The index in the choices collection this object is in.

selected - The currently selected string value

Returns:

Whether the given value represents the current selection

getChoices

public java.util.List getChoices()

Returns:

The collection of object that this choice has

setChoices

public final void setChoices(IModel choices)

Sets the list of choices

Parameters:

choices - model representing the list of choices

setChoices

public final void setChoices(java.util.List choices)

Sets the list of choices.

Parameters:

choices - the list of choices

getChoiceRenderer

public final IChoiceRenderer getChoiceRenderer()

Returns:

The IChoiceRenderer used for rendering the data objects

setChoiceRenderer

public final void setChoiceRenderer(IChoiceRenderer renderer)

Set the choice renderer to be used.

Parameters:

renderer -

detachModel

protected void detachModel()

Description copied from class: Component

Detaches the model for this component if it is detachable.

Overrides:

detachModel in class Component

See Also:

Component.detachModel()

onComponentTagBody

protected void onComponentTagBody(MarkupStream markupStream,
                                  ComponentTag openTag)

Handle the container's body.

Overrides:

onComponentTagBody in class MarkupContainer

Parameters:

markupStream - The markup stream

openTag - The open tag for the body

See Also:

Component.onComponentTagBody(MarkupStream, ComponentTag)

appendOptionHtml

protected void appendOptionHtml(AppendingStringBuffer buffer,
                                java.lang.Object choice,
                                int index,
                                java.lang.String selected)

Generats and appends html for a single choice into the provided buffer

Parameters:

buffer - Appending string buffer that will have the generated html appended

choice - Choice object

index - The index of this option

selected - The currently selected string value

supportsPersistence

protected boolean supportsPersistence()

Overrides:

supportsPersistence in class FormComponent

Returns:

True if this type of FormComponent can be persisted.

See Also:

FormComponent.supportsPersistence()

localizeDisplayValues

protected boolean localizeDisplayValues()

Override this method if you want to localize the display values of the generated options. By default false is returned so that the display values of options are not tested if they have a i18n key.

Returns:

true If you want to localize the display values, default == false