javax.faces.convert.EnumConverter Maven / Gradle / Ivy
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package javax.faces.convert;
import javax.faces.component.UIComponent;
import javax.faces.component.PartialStateHolder;
import javax.faces.context.FacesContext;
/**
* {@link Converter} implementation
* for java.lang.Enum (and enum primitive) values.
*
* @since 1.2
*/
public class EnumConverter implements Converter, PartialStateHolder {
// for StateHolder
public EnumConverter() {
}
public EnumConverter(Class targetClass) {
this.targetClass = (Class) targetClass;
}
// ------------------------------------------------------ Manifest Constants
/**
* The standard converter id for this converter.
*/
public static final String CONVERTER_ID = "javax.faces.Enum";
/**
* The message identifier of the {@link javax.faces.application.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.
*/
public static final String ENUM_ID =
"javax.faces.converter.EnumConverter.ENUM";
/**
* The message identifier of the {@link javax.faces.application.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.
*/
public static final String ENUM_NO_CLASS_ID =
"javax.faces.converter.EnumConverter.ENUM_NO_CLASS";
// ----------------------------------------------------- Converter Methods
private Class targetClass;
/**
* 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 {@link #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 {@link #ENUM_ID} message with proper parameters.
*
*
* @param context the FacesContext for this request.
* @param component the UIComponent to which this value
* will be applied.
* @param value the String value to be converted to
* Object.
* @throws ConverterException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
*/
@Override
public Object getAsObject(FacesContext context, UIComponent component,
String value) {
if (context == null || component == null) {
throw new NullPointerException();
}
if (targetClass == null) {
throw new ConverterException(
MessageFactory.getMessage(context,
ENUM_NO_CLASS_ID,
value,
MessageFactory.getLabel(context,
component)));
}
// If the specified value is null or zero-length, return null
if (value == null) {
return (null);
}
value = value.trim();
if (value.length() < 1) {
return (null);
}
try {
return Enum.valueOf(targetClass, value);
} catch (IllegalArgumentException iae) {
throw new ConverterException(
MessageFactory.getMessage(context,
ENUM_ID,
value,
value,
MessageFactory.getLabel(context,
component)), iae);
}
}
/**
* 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 {@link
* #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 {@link
* ConverterException} containing the {@link #ENUM_ID} message with
* proper parameters.
*
* @throws ConverterException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
*/
@Override
public String getAsString(FacesContext context, UIComponent component,
Object value) {
if (context == null || component == null) {
throw new NullPointerException();
}
if (targetClass == null) {
throw new ConverterException(
MessageFactory.getMessage(context,
ENUM_NO_CLASS_ID,
value,
MessageFactory.getLabel(context,
component)));
}
// If the specified value is null, return the empty string.
if (value == null) {
return "";
}
if (targetClass.isInstance(value)) {
return ((Enum)value).name();
}
throw new ConverterException(
MessageFactory.getMessage(context,
ENUM_ID,
value,
value,
MessageFactory.getLabel(context,
component)));
}
// ----------------------------------------------------------- StateHolder
@Override
public void restoreState(FacesContext facesContext, Object object) {
if (facesContext == null) {
throw new NullPointerException();
}
if (object != null) {
this.targetClass = (Class) object;
}
}
@Override
public Object saveState(FacesContext facesContext) {
if (facesContext == null) {
throw new NullPointerException();
}
if (!initialStateMarked()) {
return this.targetClass;
}
return null;
}
private boolean isTransient;
@Override
public void setTransient(boolean b) {
isTransient = b;
}
@Override
public boolean isTransient() {
return isTransient;
}
private boolean initialState;
@Override
public void markInitialState() {
initialState = true;
}
@Override
public boolean initialStateMarked() {
return initialState;
}
@Override
public void clearInitialState() {
initialState = false;
}
}