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org.apache.cocoon.forms.formmodel
Class CalculatedField

java.lang.Object
  org.apache.cocoon.forms.formmodel.AbstractWidget
      org.apache.cocoon.forms.formmodel.Field
          org.apache.cocoon.forms.formmodel.CalculatedField

All Implemented Interfaces:

ValueChangedListenerEnabled, DataWidget, SelectableWidget, Widget, ValidationErrorAware, Locatable

public class CalculatedField
extends Field

A field which calculates its value.

A calculated field is useful to create fields containing a sum, or a percentage, or any other value derived from other fields in the form.

The way the field calculates its value is determined by its CalculatedFieldAlgorithm. The algorithm is also responsible for determining which other form widgets will trigger a value calculation for this field.

Version:

$Id: CalculatedField.html 1304258 2012-03-23 10:09:27Z ilgrosso $

Field Summary

Fields inherited from class org.apache.cocoon.forms.formmodel.Field

enteredValue, required, selectionList, SUGGESTED_LABEL_ATTR, suggestionList, validationError, value, VALUE_DISPLAY_PARSE_ERROR, VALUE_DISPLAY_VALIDATION, VALUE_PARSE_ERROR, VALUE_PARSED, VALUE_UNPARSED, VALUE_VALIDATED, VALUE_VALIDATING, valueState

Fields inherited from class org.apache.cocoon.forms.formmodel.AbstractWidget

wasValid

Fields inherited from interface org.apache.cocoon.forms.formmodel.Widget

PATH_SEPARATOR

Constructor Summary

protected

CalculatedField(CalculatedFieldDefinition definition)

Method Summary

protected Object	convert(Object ret, Datatype datatype) Tries to convert the return value of the algorithm to the right value for this field datatype.
CalculatedFieldAlgorithm	getAlgorithm()
Object	getValue() Get the value of a widget.
void	initialize() Called after widget's environment has been setup, to allow for any contextual initalization, such as looking up case widgets for union widgets.
protected void	installHandlers() Installs handlers on other widgets.
protected void	readFromRequest(String newEnteredValue)
protected Object	recalculate() Calls the algorithm to perform a recaulculation.

Methods inherited from class org.apache.cocoon.forms.formmodel.Field

addValueChangedListener, applyWhitespaceTrim, broadcastEvent, generateItemSaxFragment, getDatatype, getDefinition, getFieldDefinition, getSuggestionLabel, getSuggestionList, getValidationError, getXMLElementAttributes, getXMLElementName, hasValueChangedListeners, isRequired, isSuggested, readFromRequest, removeValueChangedListener, setRequired, setSelectionList, setSelectionList, setSelectionList, setSuggestionLabel, setSuggestionList, setSuggestionList, setValidationError, setValue, validate

Methods inherited from class org.apache.cocoon.forms.formmodel.AbstractWidget

addValidator, generateDisplayData, generateLabel, generateSaxFragment, getAttribute, getChild, getCombinedState, getForm, getFullName, getId, getLocation, getName, getParent, getRequestParameterName, getState, getWidget, isValid, lookupWidget, removeAttribute, removeValidator, setAttribute, setParent, setState, toString, widgetNameChanged

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.cocoon.forms.formmodel.Widget

addValidator, generateLabel, generateSaxFragment, getAttribute, getCombinedState, getForm, getFullName, getId, getLocation, getName, getParent, getRequestParameterName, getState, getWidget, isValid, lookupWidget, removeAttribute, removeValidator, setAttribute, setParent, setState

Constructor Detail

CalculatedField

protected CalculatedField(CalculatedFieldDefinition definition)

Parameters:

definition -

Method Detail

initialize

public void initialize()

Description copied from class: AbstractWidget

Called after widget's environment has been setup, to allow for any contextual initalization, such as looking up case widgets for union widgets.

Specified by:

initialize in interface Widget

Overrides:

initialize in class Field

installHandlers

protected void installHandlers()

Installs handlers on other widgets. This both forces other widget to submit the form when their values change, and also gives this field a good optimization on calls to its algorithm.

readFromRequest

protected void readFromRequest(String newEnteredValue)

Overrides:

readFromRequest in class Field

getValue

public Object getValue()

Description copied from interface: Widget

Get the value of a widget.

Not all widgets do have a value (notably ContainerWidgets, but this method is provided here as a convenience to ease writing and avoiding casts.

Specified by:

getValue in interface Widget

Overrides:

getValue in class Field

Returns:

the value of the widget.

recalculate

protected Object recalculate()

Calls the algorithm to perform a recaulculation.

Returns:

The calculated value for this field.

convert

protected Object convert(Object ret,
                         Datatype datatype)
                  throws Exception

Tries to convert the return value of the algorithm to the right value for this field datatype.

Parameters:

ret - The return value fo the algorithm.

datatype - The target datatype.

Returns:

A converted value, or the given ret value if no conversion was possible.

Throws:

Exception

getAlgorithm

public CalculatedFieldAlgorithm getAlgorithm()

Returns:

Returns the algorithm.