org.apache.tapestry.corelib.base
Class AbstractTextField

java.lang.Object
  org.apache.tapestry.corelib.base.AbstractField
      org.apache.tapestry.corelib.base.AbstractTextField

All Implemented Interfaces:

ClientElement, Field

Direct Known Subclasses:

PasswordField, TextArea, TextField

public abstract class AbstractTextField
extends AbstractField

Abstract class for a variety of components that render some variation of a text field. Most of the hooks for user input validation are in this class.

In particular, all subclasses support the "toclient" and "parseclient" events. These two events allow the normal Translator (specified by the translate parameter, but often automatically derived by Tapestry) to be augmented.

If the component container (i.e., the page) provides an event handler method for the "toclient" event, and that handler returns a non-null string, that will be the string value sent to the client. The context passed to the event handler method is t he current value of the value parameter.

Likewise, on a form submit, the "parseclient" event handler method will be passed the string provided by the client, and may provide a non-null value as the parsed value. Returning null allows the normal translator to operate. The event handler may also throw ValidationException.

Field Summary

Fields inherited from class org.apache.tapestry.corelib.base.AbstractField

NOOP_VALIDATOR

Constructor Summary

AbstractTextField()

Method Summary

protected String	getWidth() Looks for a Width annotation and, if present, returns its value as a string.
boolean	isRequired() Returns false; most components do not support declarative validation.
protected void	processSubmission(String elementName) Method implemented by subclasses to actually do the work of processing the submission of the form.
protected abstract void	writeFieldTag(MarkupWriter writer, String value) Invoked from begin(MarkupWriter) to write out the element and attributes (typically, <input>).

Methods inherited from class org.apache.tapestry.corelib.base.AbstractField

createDefaultParameterBinding, decorateInsideField, getClientId, getControlName, getLabel, isDisabled, setDecorator, setFormSupport

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractTextField

public AbstractTextField()

Method Detail

writeFieldTag

protected abstract void writeFieldTag(MarkupWriter writer,
                                      String value)

Invoked from begin(MarkupWriter) to write out the element and attributes (typically, <input>). The controlName and clientId properties will already have been set or updated.

Generally, the subclass will invoke MarkupWriter.element(String, Object[]), and will be responsible for including an AfterRender phase method to invoke MarkupWriter.end().

Parameters:

writer - markup write to send output to

value - the value (either obtained and translated from the value parameter, or obtained from the tracker)

processSubmission

protected final void processSubmission(String elementName)

Description copied from class: AbstractField

Method implemented by subclasses to actually do the work of processing the submission of the form. The element's elementName property will already have been set. This method is only invoked if the field is not disabled.

Specified by:

processSubmission in class AbstractField

Parameters:

elementName - the name of the element (used to find the correct parameter in the request)

isRequired

public boolean isRequired()

Description copied from class: AbstractField

Returns false; most components do not support declarative validation.

Specified by:

isRequired in interface Field

Overrides:

isRequired in class AbstractField

Returns:

true if a non-blank value is required for the field

getWidth

protected final String getWidth()

Looks for a Width annotation and, if present, returns its value as a string.

Returns:

the indicated width, or null if the annotation is not present