Module org.apache.wicket.core
Package org.apache.wicket.markup.html.form

Class FormComponent<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>
Type Parameters:
T - The model object type
All Implemented Interfaces:
Serializable, Iterable<Component>, IEventSink, IEventSource, IFeedbackContributor, IConverterLocator, IGenericComponent<T,FormComponent<T>>, IMetadataContext<Serializable,Component>, IFormModelUpdateListener, IFormVisitorParticipant, ILabelProvider<String>, IHeaderContributor, IRequestableComponent, IHierarchical<Component>, IClusterable
Direct Known Subclasses:
AbstractChoice, AbstractOptions, AbstractTextComponent, Button, CheckBox, CheckGroup, FileUploadField, FormComponentPanel, RadioGroup, Select
public abstract class FormComponent<T> extends LabeledWebMarkupContainer implements IFormVisitorParticipant, IFormModelUpdateListener, IGenericComponent<T,FormComponent<T>>
An HTML form component knows how to validate itself. Validators that implement IValidator can be added to the component. They will be evaluated in the order they were added and the first Validator that returns an error message determines the error message returned by the component.

FormComponents are not versioned by default. If you need versioning for your FormComponents, you will need to call Form.setVersioned(true), which will set versioning on for the form and all form component children.

If this component is required and that fails, the error key that is used is the "Required"; if the type conversion fails, it will use the key "IConverter" if the conversion failed in a converter, or "ConversionError" if type was explicitly specified via setType(Class) or a IPropertyReflectionAwareModel was used. Notice that both "IConverter" and "ConversionError" have a more specific variant of "key.classname" where classname is the type that we failed to convert to. Classname is not full qualified, so only the actual name of the class is used. Property expressions that can be used in error messages are:

  • ${input}: the input the user did give
  • ${name}: the name of the component that failed
  • ${label}: the label of the component
Author:
Jonathan Locke, Eelco Hillenius, Johan Compagner, Igor Vaynberg (ivaynberg)
See Also:

  • Field Details

  • Constructor Details

  • Method Details

    • onBeforeRender

      protected void onBeforeRender()
      Description copied from class: Component
      Called on all visible components before any component is rendered.

      NOTE: If you override this, you *must* call super.onBeforeRender() within your implementation. Because this method is responsible for cascading Component.onBeforeRender() call to its children it is strongly recommended that super call is made at the end of the override.

      Changes to the component tree can be made only before calling super.onBeforeRender().
      Overrides:
      onBeforeRender in class Component
      See Also:

    • visitFormComponentsPostOrder

      public static <R> R visitFormComponentsPostOrder(Component component, IVisitor<? extends FormComponent<?>,R> visitor)
      Visits any form components inside component if it is a container, or component itself if it is itself a form component
      Type Parameters:
      R - the type of the visitor's result
      Parameters:
      component - starting point of the traversal
      visitor - The visitor to call
      Returns:
      the visitor's result

    • visitComponentsPostOrder

      public static <R> R visitComponentsPostOrder(Component component, IVisitor<Component,R> visitor)
      Visits any form components inside component if it is a container, or component itself if it is itself a form component
      Type Parameters:
      R - the type of the visitor's result
      Parameters:
      component - starting point of the traversal
      visitor - The visitor to call
      Returns:
      the visitor's result

    • getDefaultLabel

      public final String getDefaultLabel()
      Gets the string the component would use as a label when one was requested but no label model was set via LabeledWebMarkupContainer.getLabel(). The value of this string is usually set in a property file; if the value is not set the default value equivalent to component id will be returned.
      Returns:
      localized label

    • getDefaultLabel

      public final String getDefaultLabel(String defaultValue)
      Gets the string the component would use as a label when one was requested but no label model was set via LabeledWebMarkupContainer.getLabel(). The value of this string is usually set in a property file; if the value is not set the defaultValue will be returned.
      Parameters:
      defaultValue -
      Returns:
      localized label

    • add

      public final FormComponent<T> add(IValidator<? super T> validator)
      Adds a validator to this form component
      Parameters:
      validator - validator to be added
      Returns:
      this for chaining
      Throws:
      IllegalArgumentException - if validator is null
      See Also:

    • remove

      public final FormComponent<T> remove(IValidator<? super T> validator)
      Removes a validator from the form component.
      Parameters:
      validator - validator
      Returns:
      form component for chaining
      Throws:
      IllegalArgumentException - if validator is null or not found
      See Also:

    • add

      public final FormComponent<T> add(IValidator<? super T>... validators)
      Adds a validator to this form component.
      Parameters:
      validators - The validator(s) to be added
      Returns:
      This
      Throws:
      IllegalArgumentException - if validator is null
      See Also:

    • checkRequired

      public boolean checkRequired()
      Checks if the form component's 'required' requirement is met by first checking isRequired() to see if it has to check for requirement. If that is true then by default it checks if the input is null or an empty String Strings.isEmpty(CharSequence)

      Subclasses that overwrite this method should also call isRequired() first.

      Returns:
      true if the 'required' requirement is met, false otherwise
      See Also:

    • clearInput

      public void clearInput()
      Clears the user input.

    • error

      public void error(IValidationError error)
      Reports a validation error against this form component. The actual error is reported by creating a ValidationErrorFeedback object that holds both the validation error and the generated error message - so a custom feedback panel can have access to both.
      Parameters:
      error - validation error

    • getConvertedInput

      public final T getConvertedInput()
      Gets the converted input. The converted input is set earlier though the implementation of convertInput(). FormComponentPanel often access this method when constructing their converted input value which is often the combination of converted values of the embedded FormComponents To access the model object resulted by the full form processing, use IGenericComponent.getModelObject() instead, that is an generified version of Component.getDefaultModelObject()
      Returns:
      value of input possibly converted into an appropriate type

    • setConvertedInput

      public final void setConvertedInput(T convertedInput)
      Sets the converted input. This method is typically not called by clients, unless they override convertInput(), in which case they should call this method to update the input for this component instance.
      Parameters:
      convertedInput - the converted input

    • getForm

      public Form<?> getForm()
      Returns:
      The parent form for this form component

    • getInput

      public String getInput()
      Gets the request parameter for this component as a string.
      Returns:
      The value in the request for this component

    • getInputAsArray

      public String[] getInputAsArray()
      Gets the request parameters for this component as strings.
      Returns:
      The values in the request for this component

    • getParameterValues

      protected List<StringValue> getParameterValues(String inputName)
      Reads the value(s) of the request parameter with name inputName from either the query parameters for GET method or the request body for POST method.
      Parameters:
      inputName - The name of the request parameter
      Returns:
      The parameter's value(s)

    • getInputName

      public String getInputName()
      Gets the string to be used for the name attribute of the form element. Generated using the path from the form to the component, excluding the form itself. Override it if you want even a smaller name. E.g. if you know for sure that the id is unique within a form.
      Returns:
      The string to use as the form element's name attribute

    • getRawInput

      public final String getRawInput()
      Use hasRawInput() to check if this component has raw input because null can mean 2 things: It doesn't have rawinput or the rawinput is really null.
      Returns:
      The raw form input that is stored for this formcomponent

    • getType

      public final Class<T> getType()
      Returns:
      the type to use when updating the model for this form component

    • getValidatorKeyPrefix

      public String getValidatorKeyPrefix()
      Returns:
      prefix used when constructing validator key messages
      See Also:

    • getValidators

      public final List<IValidator<? super T>> getValidators()
      Gets an unmodifiable list of validators for this FormComponent.
      Returns:
      List of validators

    • getValue

      public final String getValue()
      Gets current value for a form component, which can be either input data entered by the user, or the component's model object if no input was provided.
      Returns:
      The value

    • hasRawInput

      public final boolean hasRawInput()
      Returns whether this component has raw input. Raw input is unconverted input straight from the client.
      Returns:
      boolean whether this component has raw input.

    • inputChanged

      public final void inputChanged()
      Used by Form to tell the FormComponent that a new user input is available

    • invalid

      public final void invalid()
      Indicate that validation of this form component failed.

    • isInputNullable

      public boolean isInputNullable()
      Gets whether this component's input can be null. By default, components that do not get input will have null values passed in for input. However, component TextField is an example (possibly the only one) that never gets a null passed in, even if the field is left empty UNLESS it has attribute disabled="disabled" set.
      Returns:
      True if this component's input can be null. Returns true by default.

    • isMultiPart

      public boolean isMultiPart()
      Returns:
      True if this component encodes data in a multipart form submit

    • isRequired

      public boolean isRequired()
      Returns:
      whether or not this component's value is required

    • isValid

      public final boolean isValid()
      Gets whether this component is 'valid'. Valid in this context means that no validation errors were reported the last time the form component was processed. This variable not only is convenient for 'business' use, but is also necessary as we don't want the form component models updated with invalid input.
      Returns:
      valid whether this component is 'valid'

    • processChildren

      public boolean processChildren()
      Description copied from interface: IFormVisitorParticipant
      Should children be traversed during visiting or should only the siblings be processed.
      Specified by:
      processChildren in interface IFormVisitorParticipant
      Returns:
      true if children should be traversed during form processing; false if only the siblings should be processed.
      See Also:

    • processInput

      public final void processInput()
      This method will retrieve the request parameter, validate it, and if valid update the model. These are the same steps as would be performed by the form. This is useful when a formcomponent is used outside a form.

    • setLabel

      public FormComponent<T> setLabel(IModel<String> labelModel)
      The value will be made available to the validator property by means of ${label}. It does not have any specific meaning to FormComponent itself.
      Overrides:
      setLabel in class LabeledWebMarkupContainer
      Parameters:
      labelModel -
      Returns:
      this for chaining

    • setModelValue

      public void setModelValue(String[] value)
      THIS METHOD IS NOT PART OF THE WICKET PUBLIC API. DO NOT USE IT! Sets the value for a form component.
      Parameters:
      value - The value

    • setRequired

      public final FormComponent<T> setRequired(boolean required)
      Sets the required flag
      Parameters:
      required -
      Returns:
      this for chaining

    • setType

      public FormComponent<T> setType(Class<?> type)
      Sets the type that will be used when updating the model for this component. If no type is specified String type is assumed.
      Parameters:
      type -
      Returns:
      this for chaining

    • updateModel

      public void updateModel()
      Updates this components model from the request, it expects that the object is already converted through the convertInput() call that is called by the validate() method when a form is being processed. By default it just does this: 
       setModelObject(getConvertedInput());
      DO NOT CALL THIS METHOD DIRECTLY UNLESS YOU ARE SURE WHAT YOU ARE DOING. USUALLY UPDATING YOUR MODEL IS HANDLED BY THE FORM, NOT DIRECTLY BY YOU.
      Specified by:
      updateModel in interface IFormModelUpdateListener

    • valid

      public final void valid()
      Called to indicate that the user input is valid.

    • validate

      public void validate()
      Performs full validation of the form component, which consists of calling validateRequired(), convertInput(), and validateValidators(). This method should only be used if the form component needs to be fully validated outside the form process.

    • convertInput

      public void convertInput()
      Converts and validates the conversion of the raw input string into the object specified by getType() and records any thrown ConversionExceptions. Converted value is available through getConvertedInput().

      Usually the user should do custom conversions by specifying an IConverter by registering it with the application by overriding Application.getConverterLocator(), or at the component level by overriding Component.getConverter(Class) .

      DO NOT CALL THIS METHOD DIRECTLY UNLESS YOU ARE SURE WHAT YOU ARE DOING. USUALLY UPDATING YOUR MODEL IS HANDLED BY THE FORM, NOT DIRECTLY BY YOU.
      See Also:

    • newValidationError

      protected ValidationError newValidationError(ConversionException cause)
      This method is called, when the validation triggered by convertInput() failed with a ConversionException, to construct a ValidationError based on the exception.

      Override this method to modify the ValidationError object, e.g. add a custom variable for message substitution: 

       new FormComponent<T>(id)
 {
        protected ValidationError newValidationError(ConversionException cause)
        {
                return super.newValidationError(cause).setVariable("foo", foovalue);
        }
 };
      Parameters:
      cause - the original cause
      Returns:
      ValidationError

    • convertValue

      protected T convertValue(String[] value) throws ConversionException
      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
      Parameters:
      value - The value can be the getInput() or through a cookie
      Returns:
      The converted value. default returns just the given value
      Throws:
      ConversionException - If input can't be converted

    • getModelValue

      protected String getModelValue()
      Returns:
      Value to return when model value is needed

    • inputAsInt

      protected final int inputAsInt()
      Gets the request parameter for this component as an int.
      Returns:
      The value in the request for this component

    • inputAsInt

      protected final int inputAsInt(int defaultValue)
      Gets the request parameter for this component as an int, using the given default in case no corresponding request parameter was found.
      Parameters:
      defaultValue - Default value to return if request does not have an integer for this component
      Returns:
      The value in the request for this component

    • inputAsIntArray

      protected final int[] inputAsIntArray()
      Gets the request parameters for this component as ints.
      Returns:
      The values in the request for this component

    • 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:

    • onComponentTag

      protected void onComponentTag(ComponentTag tag)
      Processes the component tag.
      Overrides:
      onComponentTag in class Component
      Parameters:
      tag - Tag to modify
      See Also:

    • onDetach

      protected void onDetach()
      Sets the temporary converted input value to null.
      Overrides:
      onDetach in class LabeledWebMarkupContainer
      See Also:

    • onDisabled

      protected void onDisabled(ComponentTag tag)
      Called by onComponentTag(ComponentTag) when the component is disabled. By default, this method will add a disabled="disabled" attribute to the tag. Components may override this method to tweak the tag as they think is fit.
      Parameters:
      tag - the tag that is being rendered

    • onInvalid

      protected void onInvalid()
      Handle invalidation

    • onValid

      protected void onValid()
      Handle validation

    • shouldTrimInput

      protected boolean shouldTrimInput()
      Determines whether or not this component should trim its input prior to processing it. The default value is true
      Returns:
      True if the input should be trimmed.

    • trim

      protected String trim(String string)
      Trims the input according to shouldTrimInput()
      Parameters:
      string -
      Returns:
      trimmed input if shouldTrimInput() returns true, unchanged input otherwise

    • validateRequired

      protected final void validateRequired()
      Checks if the raw input value is not null if this component is required.

    • reportRequiredError

      protected void reportRequiredError()
      Reports required error against this component

    • validateValidators

      protected final void validateValidators()
      Validates this component using the component's validators.

    • newValidatable

      public final IValidatable<T> newValidatable()
      Creates an IValidatable that can be used to validate this form component. This validatable incorporates error key lookups that correspond to this form component. This method is useful when validation needs to happen outside the regular validation workflow but error messages should still be properly reported against the form component.
      Returns:
      IValidatable for this form component

    • updateAutoLabels

      public final void updateAutoLabels(IPartialPageRequestHandler target, boolean checkAuto)
      Updates auto label css classes such as error/required during ajax updates when the labels may not be directly repainted in the response.
      Parameters:
      target - The IPartialPageRequestHandler
      checkAuto - if true then we check is the related auto-label is marked as auto before updating it.

    • updateAutoLabels

      @Deprecated(since="9.17.0, 10.0.0", forRemoval=true) public final void updateAutoLabels(AjaxRequestTarget target)
      Deprecated, for removal: This API element is subject to removal in a future version.
      method in favor of the one receiving IPartialPageRequestHandler

    • updateCollectionModel

      public static <S> void updateCollectionModel(FormComponent<Collection<S>> formComponent)
      Update the model of a FormComponent containing a Collection. If the model object does not yet exists, a new suitable collection is filled with the converted input and used as the new model object. Otherwise the existing collection is modified in-place, then IModel.setObject(Object) is called with the same instance: it allows the Model to be notified of changes even when Model.getObject() returns a different Collection at every invocation.
      Type Parameters:
      S - collection type
      Parameters:
      formComponent - the form component to update
      Throws:
      WicketRuntimeException - if the existing model object collection is unmodifiable and no setter exists
      See Also: