org.apache.wicket.markup.html.form

Class DropDownChoice<T>

java.lang.Object

org.apache.wicket.Component

org.apache.wicket.MarkupContainer

org.apache.wicket.markup.html.WebMarkupContainer

org.apache.wicket.markup.html.form.LabeledWebMarkupContainer

org.apache.wicket.markup.html.form.FormComponent<T>

org.apache.wicket.markup.html.form.AbstractChoice<T,T>

org.apache.wicket.markup.html.form.AbstractSingleSelectChoice<T>

org.apache.wicket.markup.html.form.DropDownChoice<T>

Type Parameters:

T - The model object type

All Implemented Interfaces:

Serializable, Iterable<Component>, IEventSink, IEventSource, IConverterLocator, IGenericComponent<T>, IRequestListener, IFormModelUpdateListener, IFormVisitorParticipant, ILabelProvider<String>, IOnChangeListener, IHeaderContributor, IRequestableComponent, IHierarchical<Component>, IClusterable

Direct Known Subclasses:

ListChoice

public class DropDownChoice<T>
extends AbstractSingleSelectChoice<T>
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

Field Summary

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

FLAG_CONVERT_EMPTY_INPUT_STRING_TO_NULL, VALUE_SEPARATOR

Fields inherited from class org.apache.wicket.Component

ENABLE, FLAG_INITIALIZED, FLAG_REMOVING_FROM_HIERARCHY, FLAG_RESERVED1, FLAG_RESERVED2, FLAG_RESERVED3, FLAG_RESERVED4, FLAG_RESERVED5, FLAG_RESERVED8, PARENT_PATH, PATH_SEPARATOR, RENDER, RFLAG_CONTAINER_DEQUEING

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

INTERFACE

Constructor Summary

Constructors

Constructor and Description
DropDownChoice(String id) Constructor.
DropDownChoice(String id, IModel<? extends List<? extends T>> choices) Constructor.
DropDownChoice(String id, IModel<? extends List<? extends T>> choices, IChoiceRenderer<? super T> renderer) Constructor.
DropDownChoice(String id, IModel<T> model, IModel<? extends List<? extends T>> choices) Constructor.
DropDownChoice(String id, IModel<T> model, IModel<? extends List<? extends T>> choices, IChoiceRenderer<? super T> renderer) Constructor.
DropDownChoice(String id, IModel<T> model, List<? extends T> choices) Constructor.
DropDownChoice(String id, IModel<T> model, List<? extends T> choices, IChoiceRenderer<? super T> renderer) Constructor.
DropDownChoice(String id, List<? extends T> choices) Constructor.
DropDownChoice(String id, List<? extends T> choices, IChoiceRenderer<? super T> renderer) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
protected boolean	getStatelessHint() Returns whether the component can be stateless.
protected void	onComponentTag(ComponentTag tag) Processes the component tag.
void	onSelectionChanged() Called when a selection changes.
protected void	onSelectionChanged(T newSelection) Template method that can be overridden by clients that implement IOnChangeListener to be notified by onChange events of a select element.
protected boolean	wantOnSelectionChangedNotifications() Whether this component's onSelectionChanged event handler should be called using javascript window.location if the selection changes.

Methods inherited from class org.apache.wicket.markup.html.form.AbstractSingleSelectChoice

convertChoiceIdToChoice, convertValue, getDefaultChoice, getModelValue, getNullKey, getNullKeyDisplayValue, getNullValidDisplayValue, getNullValidKey, isNullValid, isSelected, setNullValid

Methods inherited from class org.apache.wicket.markup.html.form.AbstractChoice

appendOptionHtml, detachModel, escapeOptionHtml, getChoiceRenderer, getChoices, getChoicesModel, isDisabled, localizeDisplayValues, onComponentTagBody, setChoiceRenderer, setChoices, setChoices, setOptionAttributes, setType

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

add, add, checkRequired, clearInput, convertInput, error, getConvertedInput, getDefaultLabel, getDefaultLabel, getForm, getInput, getInputAsArray, getInputName, getModel, getModelObject, getRawInput, getType, getValidatorKeyPrefix, getValidators, getValue, hasRawInput, inputAsInt, inputAsInt, inputAsIntArray, inputChanged, internalOnModelChanged, invalid, isInputNullable, isMultiPart, isRequired, isValid, newValidatable, newValidationError, onDetach, onDisabled, onInvalid, onRequired, onValid, processChildren, processInput, remove, reportRequiredError, setConvertedInput, setLabel, setModel, setModelObject, setModelValue, setRequired, shouldTrimInput, trim, updateAutoLabels, updateCollectionModel, updateModel, valid, validate, validateRequired, validateValidators, visitComponentsPostOrder, visitFormComponentsPostOrder

Methods inherited from class org.apache.wicket.markup.html.form.LabeledWebMarkupContainer

getLabel

Methods inherited from class org.apache.wicket.markup.html.WebMarkupContainer

getWebPage, getWebRequest, getWebResponse, getWebSession

Methods inherited from class org.apache.wicket.MarkupContainer

add, addDequeuedComponent, addOrReplace, autoAdd, canDequeueTag, contains, dequeue, dequeue, findComponentToDequeue, get, get, getAssociatedMarkup, getAssociatedMarkupStream, getMarkup, getMarkupType, internalAdd, internalInitialize, iterator, iterator, newDequeueContext, onAfterRenderChildren, onInitialize, onRender, queue, remove, remove, removeAll, renderAll, renderAssociatedMarkup, renderNext, replace, setDefaultModel, size, swap, toString, toString, visitChildren, visitChildren, visitChildren, visitChildren

Methods inherited from class org.apache.wicket.Component

add, addStateChange, afterRender, beforeRender, canCallListenerInterface, canCallListenerInterfaceAfterExpiry, checkComponentTag, checkComponentTagAttribute, checkHierarchyChange, clearOriginalDestination, configure, continueToOriginalDestination, debug, detach, detachModels, determineVisibility, error, exceptionMessage, fatal, findMarkupStream, findPage, findParent, findParentWithAssociatedMarkup, getAjaxRegionMarkupId, getApplication, getBehaviorById, getBehaviorId, getBehaviors, getBehaviors, getClassRelativePath, getConverter, getDefaultModel, getDefaultModelObject, getDefaultModelObjectAsString, getDefaultModelObjectAsString, getEscapeModelStrings, getFeedbackMessages, getFlag, getId, getInnermostModel, getInnermostModel, getLocale, getLocalizer, getMarkup, getMarkupAttributes, getMarkupId, getMarkupId, getMarkupIdFromMarkup, getMarkupIdImpl, getMarkupSourcingStrategy, getMetaData, getModelComparator, getOutputMarkupId, getOutputMarkupPlaceholderTag, getPage, getPageRelativePath, getParent, getPath, getRenderBodyOnly, getRequest, getRequestCycle, getRequestFlag, getResponse, getSession, getSizeInBytes, getString, getString, getString, getStyle, getVariation, hasBeenRendered, hasErrorMessage, hasFeedbackMessage, info, initModel, internalPrepareForRender, internalRenderComponent, internalRenderHead, isActionAuthorized, isAuto, isBehaviorAccepted, isEnableAllowed, isEnabled, isEnabledInHierarchy, isIgnoreAttributeModifier, isRenderAllowed, isStateless, isVersioned, isVisibilityAllowed, isVisible, isVisibleInHierarchy, markRendering, modelChanged, modelChanging, newMarkupSourcingStrategy, onAfterRender, onBeforeRender, onConfigure, onEvent, onModelChanged, onModelChanging, onRemove, prepareForRender, redirectToInterceptPage, remove, remove, render, renderComponentTag, rendered, renderHead, renderHead, renderPlaceholderTag, replaceComponentTagBody, replaceWith, sameInnermostModel, sameInnermostModel, send, setAuto, setDefaultModelObject, setEnabled, setEscapeModelStrings, setFlag, setIgnoreAttributeModifier, setMarkup, setMarkupId, setMarkupIdImpl, setMetaData, setOutputMarkupId, setOutputMarkupPlaceholderTag, setParent, setRenderBodyOnly, setRequestFlag, setResponsePage, setResponsePage, setResponsePage, setVersioned, setVisibilityAllowed, setVisible, success, urlFor, urlFor, urlFor, urlFor, urlFor, visitParents, visitParents, warn, wrap

Methods inherited from class java.lang.Object

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

Constructor Detail

DropDownChoice

public DropDownChoice(String id)

Constructor.

Parameters:

id - See Component

DropDownChoice

public DropDownChoice(String id,
              List<? extends T> choices)

Constructor.

Parameters:

id - See Component

choices - The collection of choices in the dropdown

DropDownChoice

public DropDownChoice(String id,
              List<? extends T> choices,
              IChoiceRenderer<? super T> renderer)

Constructor.

Parameters:

id - See Component

renderer - The rendering engine

choices - The collection of choices in the dropdown

DropDownChoice

public DropDownChoice(String id,
              IModel<T> model,
              List<? extends T> choices)

Constructor.

Parameters:

id - See Component

model - See Component

choices - The collection of choices in the dropdown

DropDownChoice

public DropDownChoice(String id,
              IModel<T> model,
              List<? extends T> choices,
              IChoiceRenderer<? super T> renderer)

Constructor.

Parameters:

id - See Component

model - See Component

choices - The drop down choices

renderer - The rendering engine

DropDownChoice

public DropDownChoice(String id,
              IModel<? extends List<? extends T>> choices)

Constructor.

Parameters:

id - See Component

choices - The collection of choices in the dropdown

DropDownChoice

public DropDownChoice(String id,
              IModel<T> model,
              IModel<? extends List<? extends T>> choices)

Constructor.

Parameters:

id - See Component

model - See Component

choices - The drop down choices

DropDownChoice

public DropDownChoice(String id,
              IModel<? extends List<? extends T>> choices,
              IChoiceRenderer<? super T> renderer)

Constructor.

Parameters:

id - See Component

choices - The drop down choices

renderer - The rendering engine

DropDownChoice

public DropDownChoice(String id,
              IModel<T> model,
              IModel<? extends List<? extends T>> choices,
              IChoiceRenderer<? super T> renderer)

Constructor.

Parameters:

id - See Component

model - See Component

choices - The drop down choices

renderer - The rendering engine

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<T>

Parameters:

tag - Tag to modify

See Also:

Component.onComponentTag(org.apache.wicket.markup.ComponentTag)

onSelectionChanged

protected void onSelectionChanged(T newSelection)

Template method that can be overridden 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 be called using javascript window.location 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. If you wish to use Ajax instead, let wantOnSelectionChangedNotifications() return false and add an AjaxFormComponentUpdatingBehavior to the component using the onchange event.

Returns:

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

getStatelessHint

protected boolean getStatelessHint()

Returns whether the component can be stateless. Also the component behaviors must be stateless, otherwise the component will be treat as stateful. In order for page to be stateless (and not to be stored in session), all components (and component behaviors) must be stateless.

Overrides:

getStatelessHint in class Component

Returns:

whether the component can be stateless