JSF Generic converter for Entities, Enums, etc.

Identifiable.java

package org.teste.model;

public interface Identifiable<T> {

	public T getId();
}

IdentifiableConverter.java

package org.teste.view.converter;

import java.text.MessageFormat;
import java.util.HashMap;
import java.util.Map;

import javax.faces.component.PartialStateHolder;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.convert.FacesConverter;

import org.teste.model.Identifiable;

@SuppressWarnings("rawtypes")
public class IdentifiableConverter implements Converter, PartialStateHolder {
	
	private Map<String, Identifiable> values;

	@Override
	public Object getAsObject(FacesContext context, UIComponent component, String value) {
		if (value == null) 
			return null;
		
		for (Map.Entry<String, Identifiable> entry : values.entrySet()) {
			if (value.equals(entry.getKey())) {
				return entry.getValue();
			}
		}
		
		return null;
	}

	@Override
	public String getAsString(FacesContext context, UIComponent component, Object value) {
		if (!(value instanceof Identifiable)) {
			throw new IllegalArgumentException(
					MessageFormat.format("The value {0} is not an instance of Identifiable", value));
		}
		
		if (values == null) {
			values = new HashMap<>();
		}
		
		Identifiable identifiable = (Identifiable) value;
		String string = identifiable.getId().toString();
		
		values.put(string, identifiable);
		
		return string;
	}

	@Override
	public Object saveState(FacesContext context) {
		return values;
	}

	@SuppressWarnings("unchecked")
	@Override
	public void restoreState(FacesContext context, Object state) {
		values = (Map<String, Identifiable>) state;
	}

	private boolean isTransient;
	
	@Override
	public boolean isTransient() {
		return isTransient;
	}

	@Override
	public void setTransient(boolean b) {
		isTransient = b;
	}
	
	private boolean initialState;

	@Override
	public void markInitialState() {
		initialState = true;
	}

	@Override
	public boolean initialStateMarked() {
		return initialState;
	}

	@Override
	public void clearInitialState() {
		initialState = false;
	}
}