jakarta.faces.convert.EnumConverter Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2021 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package jakarta.faces.convert;
import jakarta.faces.component.PartialStateHolder;
import jakarta.faces.component.UIComponent;
import jakarta.faces.context.FacesContext;
/**
*
* {@link Converter} implementation for
* java.lang.Enum (and enum primitive) values.
*
*
* @since 1.2
*/
public class EnumConverter implements Converter, PartialStateHolder {
/**
*
* The standard converter id for this converter.
*
*/
public static final String CONVERTER_ID = "jakarta.faces.Enum";
// ------------------------------------------------------ Manifest Constants
/**
*
* The message identifier of the {@link jakarta.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 = "jakarta.faces.converter.EnumConverter.ENUM";
/**
*
* The message identifier of the {@link jakarta.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 = "jakarta.faces.converter.EnumConverter.ENUM_NO_CLASS";
private Class targetClass;
private boolean isTransient;
private boolean initialState;
/**
* For StateHolder
*/
public EnumConverter() {
}
/**
* Instantiates an enum converter with a class where enum constants are taken from.
*
* @param targetClass Class where the enum constants are taken from by the converter methods.
*/
public EnumConverter(Class targetClass) {
this.targetClass = targetClass;
}
// ----------------------------------------------------- Converter Methods
/**
*
* 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) {
targetClass = (Class) object;
}
}
@Override
public Object saveState(FacesContext facesContext) {
if (facesContext == null) {
throw new NullPointerException();
}
if (!initialStateMarked()) {
return targetClass;
}
return null;
}
@Override
public void setTransient(boolean b) {
isTransient = b;
}
@Override
public boolean isTransient() {
return isTransient;
}
@Override
public void markInitialState() {
initialState = true;
}
@Override
public boolean initialStateMarked() {
return initialState;
}
@Override
public void clearInitialState() {
initialState = false;
}
}