// ========================================================================
// Copyright (c) 2004-2009 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
// The Eclipse Public License is available at 
// http://www.eclipse.org/legal/epl-v10.html
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
// You may elect to redistribute this code under either of these licenses. 
// ========================================================================
package net.hasor.utils.json;
import java.lang.reflect.Method;
import java.util.Map;
import java.util.logging.Logger;
/* ------------------------------------------------------------ */

/**
 * Convert an {@link Enum} to JSON.
 * If fromJSON is true in the constructor, the JSON generated will
 * be of the form {class="com.acme.TrafficLight",value="Green"}
 * If fromJSON is false, then only the string value of the enum is generated.
 */
public class JSONEnumConvertor implements JSON.Convertor {
    protected final static Logger  logger = Logger.getLogger(JSONEnumConvertor.class.getName());
    private                boolean _fromJSON;
    private                Method  _valueOf;

    {
        try {
            Class e = Loader.loadClass(getClass(), "java.lang.Enum");
            _valueOf = e.getMethod("valueOf", new Class[] { Class.class, String.class });
        } catch (Exception e) {
            throw new RuntimeException("!Enums", e);
        }
    }

    public JSONEnumConvertor() {
        this(false);
    }

    public JSONEnumConvertor(boolean fromJSON) {
        _fromJSON = fromJSON;
    }

    public Object fromJSON(Map map) {
        if (!_fromJSON)
            throw new UnsupportedOperationException();
        try {
            Class c = Loader.loadClass(getClass(), (String) map.get("class"));
            return _valueOf.invoke(null, new Object[] { c, map.get("value") });
        } catch (Exception e) {
            logger.warning(e.getMessage());
        }
        return null;
    }

    public void toJSON(Object obj, JSON.Output out) {
        if (_fromJSON) {
            out.addClass(obj.getClass());
            out.add("value", obj.toString());
        } else {
            out.add(obj.toString());
        }
    }
}