wicket.markup.html.form
Class Form

java.lang.Object
  wicket.Component
      wicket.MarkupContainer
          wicket.markup.html.WebMarkupContainer
              wicket.markup.html.form.Form

All Implemented Interfaces:

java.io.Serializable, IRequestListener, IFormSubmitListener

public class Form
extends WebMarkupContainer
implements IFormSubmitListener

Base class for forms. To implement a form, subclass this class, add FormComponents (such as CheckBoxes, ListChoices or TextFields) to the form. You can nest multiple buttons if you want to vary submit behavior. However, it is not necessary to use Wicket's button class, just putting e.g. <input type="submit" value="go"> suffices.

By default, the processing of a form works like this:

The submitting button is looked up. A submitting button is a button that is nested in this form (is a child component) and that was clicked by the user. If a submitting button was found, and it has the defaultFormProcessing field set to false (default is true), it's onSubmit method will be called right away, thus no validition is done, and things like updating form component models that would normally be done are skipped. In that respect, nesting a button with the defaultFormProcessing field set to false has the same effect as nesting a normal link. If you want you can call validate() to execute form validation, hasError() to find out whether validate() resulted in validation errors, and updateFormComponentModels() to update the models of nested form components.

When no submitting button with defaultFormProcessing set to false was found, this form is processed (method process()). Now, two possible paths exist:

• Form validation failed. All nested form components will be marked invalid, and onError() is called to allow clients to provide custom error handling code.
• Form validation succeeded. The nested components will be asked to update their models and persist their data is applicable. After that, method delegateSubmit with optionally the submitting button is called. The default when there is a submitting button is to first call onSubmit on that button, and after that call onSubmit on this form. Clients may override delegateSubmit if they want different behavior.

Form for handling (file) uploads with multipart requests is supported by callign setMultiPart(true) ( although wicket will try to automatically detect this for you ). Use this with FileUploadField components. You can attach mutliple FileUploadField components for muliple file uploads.

In case of an upload error two resource keys are available to specify error messages: uploadTooLarge and uploadFailed ie in [page].properties [form-id].uploadTooLarge=You have uploaded a file that is over the allowed limit of 2Mb

If you want to have multiple buttons which submit the same form, simply put two or more button components somewhere in the hierarchy of components that are children of the form.

To get form components to persist their values for users via cookies, simply call setPersistent(true) on the form component.

Author:

Jonathan Locke, Juergen Donnerstag, Eelco Hillenius, Cameron Braid, Johan Compagner, Igor Vaynberg (ivaynberg)

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class wicket.Component

Component.ComponentModelChange, Component.EnabledChange, Component.IVisitor, Component.VisibilityChange

Field Summary

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.IFormSubmitListener

INTERFACE

Constructor Summary

Form(java.lang.String id)
Constructs a form with no validation.

Form(java.lang.String id, IModel model)

Method Summary

void	add(IFormValidator validator) Adds a form validator to the form.
protected void	appendDefaultButtonField(MarkupStream markupStream, ComponentTag openTag) If a default button was set on this form, this method will be called to render an extra field with an invisible style so that pressing enter in one of the textfields will do a form submit using this button.
protected void	beforeUpdateFormComponentModels() Template method to allow clients to do any processing (like recording the current model so that, in case onSubmit does further validation, the model can be rolled back) before the actual updating of form component models is done.
void	clearInput() Clears the input from the form's nested children of type FormComponent.
protected void	delegateSubmit(Button submittingButton) Called (by the default implementation of 'process') when all fields validated, the form was updated and it's data was allowed to be persisted.
void	error(java.lang.String error, java.util.Map args) /** Registers an error feedback message for this component
Button	findSubmittingButton() Gets the button which submitted this form.
Button	getDefaultButton() Gets the default button.
protected java.lang.String	getHiddenFieldId() Returns the HiddenFieldId which will be used as the name and id property of the hiddenfield that is generated for event dispatches.
protected java.lang.String	getJavascriptId() Returns the javascript/css id of this form that will be used to generated the id="xxx" attribute.
java.lang.CharSequence	getJsForInterfaceUrl(java.lang.CharSequence url) This generates a piece of javascript code that sets the url in the special hidden field and submits the form.
Bytes	getMaxSize()
java.lang.String	getValidatorKeyPrefix() Returns the prefix used when building validator keys.
protected IValuePersister	getValuePersister() Gets the form component persistence manager; it is lazy loaded.
boolean	hasError() Gets whether the current form has any error registered.
protected void	internalOnDetach() THIS METHOD IS NOT PART OF THE WICKET PUBLIC API.
protected void	internalOnModelChanged() THIS METHOD IS NOT PART OF THE WICKET PUBLIC API.
boolean	isSubmitted() Checks if this form has been submitted during the current request
boolean	isVersioned() Method made final because we want to ensure users call setVersioned.
void	loadPersistentFormComponentValues() THIS METHOD IS NOT PART OF THE WICKET PUBLIC API.
protected void	markFormComponentsInvalid() Mark each form component on this form invalid.
protected void	markFormComponentsValid() Mark each form component on this form valid.
protected void	onComponentTag(ComponentTag tag) Processes the component tag.
protected void	onComponentTagBody(MarkupStream markupStream, ComponentTag openTag) Append an additional hidden input tag to support anchor tags that can submit a form.
protected void	onError() Method to override if you want to do something special when an error occurs (other than simply displaying validation errors).
void	onFormSubmitted() THIS METHOD IS NOT PART OF THE WICKET API.
protected void	onRender(MarkupStream markupStream) Renders this component.
protected void	onSubmit() Implemented by subclasses to deal with form submits.
boolean	process() Process the form.
void	removePersistentFormComponentValues(boolean disablePersistence) Removes already persisted data for all FormComponent childs and disable persistence for the same components.
void	setDefaultButton(Button button) Sets the default button.
void	setMaxSize(Bytes maxSize)
void	setMultiPart(boolean multiPart) Set to true to use enctype='multipart/form-data', and to process file uplloads by default multiPart = false
Component	setVersioned(boolean isVersioned)
protected void	updateFormComponentModels() Update the model of all form components using the fields that were sent with the current request.
protected void	validate() Validates the form.
protected void	validateFormValidator(IFormValidator validator) Validates form with the given form validator
void	visitFormComponents(FormComponent.IVisitor visitor) Convenient and typesafe way to visit all the form components on a form

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, 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, detachModel, 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, isActionAuthorized, isAncestorOf, isBehaviorAccepted, isEnableAllowed, isEnabled, isHeadRendered, isIgnoreAttributeModifier, isRenderAllowed, isVisible, isVisibleInHierarchy, modelChanged, modelChanging, newPage, newPage, onAfterRender, onAttach, onBeforeRender, onBeginRequest, onDetach, 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, 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

Form

public Form(java.lang.String id)

Constructs a form with no validation.

Parameters:

id - See Component

Form

public Form(java.lang.String id,
            IModel model)

Parameters:

id - See Component

model - See Component

See Also:

Component.Component(String, IModel)

Method Detail

getDefaultButton

public final Button getDefaultButton()

Gets the default button. If set (not null), a hidden submit button will be rendered right after the form tag, so that when users press enter in a textfield, this button's action will be selected. If no default button is set (it is null), nothing additional is rendered.

WARNING: note that this is a best effort only. Unfortunately having a 'default' button in a form is ill defined in the standards, and of course IE has it's own way of doing things.

Returns:

The button to set as the default button, or null when you want to 'unset' any previously set default button

getMaxSize

public Bytes getMaxSize()

Returns:

the maxSize of uploaded files

loadPersistentFormComponentValues

public final void loadPersistentFormComponentValues()

THIS METHOD IS NOT PART OF THE WICKET PUBLIC API. DO NOT CALL IT.

Retrieves FormComponent values related to the page using the persister and assign the values to the FormComponent. Thus initializing them.

onFormSubmitted

public final void onFormSubmitted()

THIS METHOD IS NOT PART OF THE WICKET API. DO NOT ATTEMPT TO OVERRIDE OR CALL IT. Handles form submissions.

Specified by:

onFormSubmitted in interface IFormSubmitListener

See Also:

validate()

isSubmitted

public final boolean isSubmitted()

Checks if this form has been submitted during the current request

Returns:

true if the form has been submitted during this request, false otherwise

internalOnDetach

protected void internalOnDetach()

Description copied from class: Component

THIS METHOD IS NOT PART OF THE WICKET PUBLIC API. DO NOT CALL OR OVERRIDE. Called when a request ends.

Overrides:

internalOnDetach in class Component

See Also:

Component.internalOnDetach()

removePersistentFormComponentValues

public void removePersistentFormComponentValues(boolean disablePersistence)

Removes already persisted data for all FormComponent childs and disable persistence for the same components.

Parameters:

disablePersistence - if true, disable persistence for all FormComponents on that page. If false, it will remain unchanged.

See Also:

Page.removePersistedFormData(Class, boolean)

setDefaultButton

public final void setDefaultButton(Button button)

Sets the default button. If set (not null), a hidden submit button will be rendered right after the form tag, so that when users press enter in a textfield, this button's action will be selected. If no default button is set (so unset by calling this method with null), nothing additional is rendered.

WARNING: note that this is a best effort only. Unfortunately having a 'default' button in a form is ill defined in the standards, and of course IE has it's own way of doing things.

Parameters:

button - The button to set as the default button, or null when you want to 'unset' any previously set default button

setMaxSize

public void setMaxSize(Bytes maxSize)

Parameters:

maxSize - The maxSize for uploaded files

setMultiPart

public void setMultiPart(boolean multiPart)

Set to true to use enctype='multipart/form-data', and to process file uplloads by default multiPart = false

Parameters:

multiPart - whether this form should behave as a multipart form

setVersioned

public final Component setVersioned(boolean isVersioned)

Overrides:

setVersioned in class Component

Parameters:

isVersioned - True to turn on versioning for this component, false to turn it off for this component and any children.

Returns:

This

See Also:

Component.setVersioned(boolean)

isVersioned

public boolean isVersioned()

Method made final because we want to ensure users call setVersioned.

Overrides:

isVersioned in class Component

Returns:

True if this component is versioned

See Also:

Component.isVersioned()

visitFormComponents

public final void visitFormComponents(FormComponent.IVisitor visitor)

Convenient and typesafe way to visit all the form components on a form

Parameters:

visitor - The visitor interface to call

appendDefaultButtonField

protected void appendDefaultButtonField(MarkupStream markupStream,
                                        ComponentTag openTag)

If a default button was set on this form, this method will be called to render an extra field with an invisible style so that pressing enter in one of the textfields will do a form submit using this button. This method is overridable as what we do is best effort only, and may not what you want in specific situations. So if you have specific usability concerns, or want to follow another strategy, you may override this method.

Parameters:

markupStream - The markup stream

openTag - The open tag for the body

beforeUpdateFormComponentModels

protected void beforeUpdateFormComponentModels()

Template method to allow clients to do any processing (like recording the current model so that, in case onSubmit does further validation, the model can be rolled back) before the actual updating of form component models is done.

delegateSubmit

protected void delegateSubmit(Button submittingButton)

Called (by the default implementation of 'process') when all fields validated, the form was updated and it's data was allowed to be persisted. It is meant for delegating further processing to clients.

This implementation first finds out whether the form processing was triggered by a nested button of this form. If that is the case, that button's onSubmit is called first.

Regardless of whether a submitting button was found, the form's onSubmit method is called next.

Parameters:

submittingButton - the button that triggered this form processing, or null if the processing was triggered by something else (like a non-Wicket submit button or a javascript execution)

findSubmittingButton

public final Button findSubmittingButton()

Gets the button which submitted this form.

Returns:

The button which submitted this form or null if the processing was not trigger by a registered button component

getValuePersister

protected IValuePersister getValuePersister()

Gets the form component persistence manager; it is lazy loaded.

Returns:

The form component value persister

hasError

public final boolean hasError()

Gets whether the current form has any error registered.

Returns:

True if this form has at least one error.

internalOnModelChanged

protected void internalOnModelChanged()

Description copied from class: Component

THIS METHOD IS NOT PART OF THE WICKET PUBLIC API. DO NOT CALL OR OVERRIDE. Called anytime a model is changed via setModel or setModelObject.

Overrides:

internalOnModelChanged in class Component

See Also:

Component.internalOnModelChanged()

markFormComponentsInvalid

protected final void markFormComponentsInvalid()

Mark each form component on this form invalid.

markFormComponentsValid

protected final void markFormComponentsValid()

Mark each form component on this form valid.

getHiddenFieldId

protected final java.lang.String getHiddenFieldId()

Returns the HiddenFieldId which will be used as the name and id property of the hiddenfield that is generated for event dispatches.

Returns:

The name and id of the hidden field.

getJavascriptId

protected final java.lang.String getJavascriptId()

Returns the javascript/css id of this form that will be used to generated the id="xxx" attribute. it will be generated if not set already in the onComponentTag. Where it will be tried to load from the markup first before it is generated.

Returns:

The javascript/css id of this form.

onComponentTagBody

protected void onComponentTagBody(MarkupStream markupStream,
                                  ComponentTag openTag)

Append an additional hidden input tag to support anchor tags that can submit a form.

Overrides:

onComponentTagBody in class MarkupContainer

Parameters:

markupStream - The markup stream

openTag - The open tag for the body

onComponentTag

protected void onComponentTag(ComponentTag tag)

Description copied from class: Component

Processes the component tag.

Overrides:

onComponentTag in class Component

Parameters:

tag - Tag to modify

See Also:

Component.onComponentTag(ComponentTag)

onError

protected void onError()

Method to override if you want to do something special when an error occurs (other than simply displaying validation errors).

onRender

protected void onRender(MarkupStream markupStream)

Description copied from class: MarkupContainer

Renders this component. This implementation just calls renderComponent.

Overrides:

onRender in class MarkupContainer

See Also:

Component.onRender(MarkupStream)

onSubmit

protected void onSubmit()

Implemented by subclasses to deal with form submits.

process

public boolean process()

Process the form. Though you can override this method to provide your whole own algorithm, it is not recommended to do so.

See the class documentation for further details on the form processing

Returns:

False if the form had an error

updateFormComponentModels

protected final void updateFormComponentModels()

Update the model of all form components using the fields that were sent with the current request.

See Also:

FormComponent.updateModel()

clearInput

public final void clearInput()

Clears the input from the form's nested children of type FormComponent. This method is typically called when a form needs to be reset.

validate

protected void validate()

Validates the form. This method is typically called before updating any models.

validateFormValidator

protected final void validateFormValidator(IFormValidator validator)

Validates form with the given form validator

Parameters:

validator -

getJsForInterfaceUrl

public final java.lang.CharSequence getJsForInterfaceUrl(java.lang.CharSequence url)

This generates a piece of javascript code that sets the url in the special hidden field and submits the form. Warning: This code should only be called in the rendering phase for form components inside the form because it uses the css/javascript id of the form which can be stored in the markup.

Parameters:

url - The interface url that has to be stored in the hidden field and submitted

Returns:

The javascript code that submits the form.

getValidatorKeyPrefix

public java.lang.String getValidatorKeyPrefix()

Returns the prefix used when building validator keys. This allows a form to use a separate "set" of keys. For example if prefix "short" is returned, validator key short.RequiredValidator will be tried instead of RequiredValidator key.

This can be useful when different designs are used for a form. In a form where error messages are displayed next to their respective form components as opposed to at the top of the form, the ${label} attribute is of little use and only causes redundant information to appear in the message. Forms like these can return the "short" (or any other string) validator prefix and declare key: short.RequiredValidator=required to override the longer message which is usually declared like this: RequiredValidator=${label} is a required field

Returned prefix will be used for all form components. The prefix can also be overridden on form component level by overriding FormComponent.getValidatorKeyPrefix()

Returns:

prefix prepended to validator keys

add

public void add(IFormValidator validator)

Adds a form validator to the form.

Parameters:

validator - validator

See Also:

IFormValidator

error

public final void error(java.lang.String error,
                        java.util.Map args)

/** Registers an error feedback message for this component

Parameters:

error - error message

args - argument replacement map for ${key} variables