Module jakarta.faces

Package jakarta.faces.convert

Class EnumConverter

java.lang.Object

jakarta.faces.convert.EnumConverter

All Implemented Interfaces:

PartialStateHolder, StateHolder, Converter

public class EnumConverter
extends Object
implements Converter, PartialStateHolder

Converter implementation for java.lang.Enum (and enum primitive) values.

Since:

1.2

Field Summary

Fields

Modifier and Type	Field	Description
static final String	CONVERTER_ID	The standard converter id for this converter.
static final String	ENUM_ID	The message identifier of the FacesMessage to be created if the conversion to Enum fails.
static final String	ENUM_NO_CLASS_ID	The message identifier of the FacesMessage to be created if the conversion to Enum fails and no target class has been provided.

Fields inherited from interface jakarta.faces.convert.Converter

DATETIMECONVERTER_DEFAULT_TIMEZONE_IS_SYSTEM_TIMEZONE_PARAM_NAME

Constructor Summary

Constructors

Constructor	Description
EnumConverter()	For StateHolder
EnumConverter(Class targetClass)	Instantiates an enum converter with a class where enum constants are taken from.

Method Summary

Modifier and Type	Method	Description
void	clearInitialState()	Reset the PartialStateHolder to a non-delta tracking state.
Object	getAsObject(FacesContext context, UIComponent component, String value)	Convert the value argument to one of the enum constants of the class provided in our constructor.
String	getAsString(FacesContext context, UIComponent component, Object value)	Convert the enum constant given by the value argument into a String.
boolean	initialStateMarked()	Return true if delta state changes are being tracked, otherwise false
boolean	isTransient()	If true, the Object implementing this interface must not participate in state saving or restoring.
void	markInitialState()	The runtime must ensure that the PartialStateHolder.markInitialState() method is called on each instance of this interface in the view at the appropriate time to indicate the component is in its initial state.
void	restoreState(FacesContext facesContext, Object object)	Perform any processing required to restore the state from the entries in the state Object.
Object	saveState(FacesContext facesContext)	Gets the state of the instance as a Serializable Object.
void	setTransient(boolean b)	Denotes whether or not the Object implementing this interface must or must not participate in state saving or restoring.

Methods inherited from class java.lang.Object

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

Field Details

CONVERTER_ID

public static final String CONVERTER_ID

The standard converter id for this converter.

See Also:

• Constant Field Values

ENUM_ID

public static final String ENUM_ID

The message identifier of the FacesMessage to be created if the conversion to Enum fails. The message format string for this message may optionally include the following placeholders:

• {0} replaced by the unconverted value.
• {1} replaced by one of the enum constants or the empty string if none can be found.
• {2} replaced by a String whose value is the label of the input component that produced this message.

See Also:

• Constant Field Values

ENUM_NO_CLASS_ID

public static final String ENUM_NO_CLASS_ID

The message identifier of the FacesMessage to be created if the conversion to Enum fails and no target class has been provided. The message format string for this message may optionally include the following placeholders:

• {0} replaced by the unconverted value.
• {1} replaced by a String whose value is the label of the input component that produced this message.

See Also:

• Constant Field Values

Constructor Details

EnumConverter

public EnumConverter()

For StateHolder

EnumConverter

public EnumConverter(Class targetClass)

Instantiates an enum converter with a class where enum constants are taken from.

Parameters:

targetClass - Class where the enum constants are taken from by the converter methods.

Method Details

getAsObject

public Object getAsObject(FacesContext context,
 UIComponent component,
 String value)

Convert the value argument to one of the enum constants of the class provided in our constructor. If no target class argument has been provided to the constructor of this instance, throw a ConverterException containing the ENUM_NO_CLASS_ID message with proper parameters. If the value argument is null or it has a length of zero, return null. Otherwise, perform the equivalent of Enum.valueOf using target class and value and return the Object. If the conversion fails, throw a ConverterException containing the ENUM_ID message with proper parameters.

Specified by:

getAsObject in interface Converter

Parameters:

context - the FacesContext for this request.

component - the UIComponent to which this value will be applied.

value - the String value to be converted to Object.

Returns:

null if the value to convert is null, otherwise the result of the conversion

Throws:

ConverterException - if conversion cannot be successfully performed

NullPointerException - if context or component is null

getAsString

public String getAsString(FacesContext context,
 UIComponent component,
 Object value)

Convert the enum constant given by the value argument into a String. If no target class argument has been provided to the constructor of this instance, throw a ConverterException containing the ENUM_NO_CLASS_ID message with proper parameters. If the value argument is null, return the empty String. If the value is an instance of the provided target class, return its string value by casting it to a java.lang.Enum and returning the result of calling the name() method. Otherwise, throw a ConverterException containing the ENUM_ID message with proper parameters.

Specified by:

getAsString in interface Converter

Parameters:

context - FacesContext for the request being processed

component - UIComponent with which this model object value is associated

value - Model object value to be converted (may be null)

Returns:

a zero-length String if value is null, otherwise the result of the conversion

Throws:

ConverterException - if conversion cannot be successfully performed

NullPointerException - if context or component is null

restoreState

public void restoreState(FacesContext facesContext,
 Object object)

Description copied from interface: StateHolder

Perform any processing required to restore the state from the entries in the state Object.

If the class that implements this interface has references to instances that also implement StateHolder (such as a UIComponent with event handlers, validators, etc.) this method must call the StateHolder.restoreState(jakarta.faces.context.FacesContext, java.lang.Object) method on all those instances as well.

If the state argument is null, take no action and return.

Specified by:

restoreState in interface StateHolder

Parameters:

facesContext - the Faces context.

object - the state.

saveState

public Object saveState(FacesContext facesContext)

Description copied from interface: StateHolder

Gets the state of the instance as a Serializable Object.

If the class that implements this interface has references to instances that implement StateHolder (such as a UIComponent with event handlers, validators, etc.) this method must call the StateHolder.saveState(jakarta.faces.context.FacesContext) method on all those instances as well. This method must not save the state of children and facets. That is done via the StateManager

This method must not alter the state of the implementing object. In other words, after executing this code:

 
 Object state = component.saveState(facesContext);
 
 

component should be the same as before executing it.

The return from this method must be Serializable

Specified by:

saveState in interface StateHolder

Parameters:

facesContext - the Faces context.

Returns:

the saved state.

setTransient

public void setTransient(boolean b)

Description copied from interface: StateHolder

Denotes whether or not the Object implementing this interface must or must not participate in state saving or restoring.

Specified by:

setTransient in interface StateHolder

Parameters:

b - boolean pass true if this Object will not participate in state saving or restoring, otherwise pass false.

isTransient

public boolean isTransient()

Description copied from interface: StateHolder

If true, the Object implementing this interface must not participate in state saving or restoring.

Specified by:

isTransient in interface StateHolder

Returns:

true if transient, false otherwise.

markInitialState

public void markInitialState()

Description copied from interface: PartialStateHolder

The runtime must ensure that the PartialStateHolder.markInitialState() method is called on each instance of this interface in the view at the appropriate time to indicate the component is in its initial state. The implementor of the interface must ensure that PartialStateHolder.initialStateMarked() returns true from the time markInitialState() is called until PartialStateHolder.clearInitialState() is called, after which time initialStateMarked() must return false. Also, during the time that the instance returns true from initialStateMarked(), the implementation must return only the state that has changed in its implementation of StateHolder.saveState(jakarta.faces.context.FacesContext).

Specified by:

markInitialState in interface PartialStateHolder

initialStateMarked

public boolean initialStateMarked()

Description copied from interface: PartialStateHolder

Return true if delta state changes are being tracked, otherwise false

Specified by:

initialStateMarked in interface PartialStateHolder

Returns:

true if the initial state is marked, false otherwise.

clearInitialState

public void clearInitialState()

Description copied from interface: PartialStateHolder

Reset the PartialStateHolder to a non-delta tracking state.

Specified by:

clearInitialState in interface PartialStateHolder