wicket.markup.html.form
Class DropDownChoice

java.lang.Object
  extended by wicket.Component
      extended by wicket.MarkupContainer
          extended by wicket.markup.html.WebMarkupContainer
              extended by wicket.markup.html.form.FormComponent
                  extended by 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: 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


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