EnumConverter (Jakarta EE 8 Specification APIs)

java.lang.Object
- javax.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 and Description
`static String`	`CONVERTER_ID` The standard converter id for this converter.
`static String`	`ENUM_ID` The message identifier of the `FacesMessage` to be created if the conversion to `Enum` fails.
`static 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 javax.faces.convert.Converter
DATETIMECONVERTER_DEFAULT_TIMEZONE_IS_SYSTEM_TIMEZONE_PARAM_NAME

Constructor Summary

Constructors
Constructor and Description

EnumConverter()

EnumConverter(Class targetClass)

Constructors
Constructor and Description
`EnumConverter()`
`EnumConverter(Class targetClass)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and 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 Detail
  - 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 Detail
  - EnumConverter
```
public EnumConverter()
```
  - EnumConverter
```
public EnumConverter(Class targetClass)
```
- Method Detail
  - 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(javax.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(javax.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(javax.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

Class EnumConverter

Field Summary

Fields inherited from interface javax.faces.convert.Converter

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

CONVERTER_ID

ENUM_ID

ENUM_NO_CLASS_ID

Constructor Detail

EnumConverter

EnumConverter

Method Detail

getAsObject

getAsString

restoreState

saveState

setTransient

isTransient

markInitialState

initialStateMarked

clearInitialState