EnumInstantiator.java

/**
 *   GRANITE DATA SERVICES
 *   Copyright (C) 2006-2015 GRANITE DATA SERVICES S.A.S.
 *
 *   This file is part of the Granite Data Services Platform.
 *
 *   Granite Data Services is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU Lesser General Public
 *   License as published by the Free Software Foundation; either
 *   version 2.1 of the License, or (at your option) any later version.
 *
 *   Granite Data Services is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
 *   General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
 *   USA, or see <http://www.gnu.org/licenses/>.
 */
package org.granite.messaging.amf.io.util.instantiator;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.granite.messaging.service.ServiceException;
import org.granite.util.TypeUtil;

/**
 * @author Igor SAZHNEV
 */
public class EnumInstantiator extends AbstractInstantiator<Enum<?>> {

    private static final long serialVersionUID = -6116814787518316453L;

    private final String type;

    private static final List<String> orderedFields;
    static {
        List<String> of = new ArrayList<String>(1);
        of.add("value");
        orderedFields = Collections.unmodifiableList(of);
    }

    public EnumInstantiator(String type) {
        this.type = type;
    }

    @Override
    public List<String> getOrderedFieldNames() {
        return orderedFields;
    }

    @SuppressWarnings({ "unchecked", "rawtypes" })
    @Override
    public Enum<?> newInstance() {
        Enum<?> enumInstance = null;

        String enumValue = null;
        try {
            Class<? extends Enum> enumClass = (Class<? extends Enum>)TypeUtil.forName(type);
            enumValue = (String)get("value");
            if (enumValue == null) {
                Object[] enumConstants = enumClass.getEnumConstants();
                if (enumConstants == null || enumConstants.length == 0)
                    throw new ServiceException("Invalid Enum type: " + type);
                enumValue = ((Enum<?>)enumConstants[0]).name();
            }
            enumInstance = Enum.valueOf(enumClass, enumValue);
        } catch (ClassNotFoundException e) {
            throw new ServiceException("Could not find Enum type for: " + type, e);
        } catch (IllegalArgumentException e) {
            throw new ServiceException("Could not find Enum constant for: " + type + '.' + enumValue, e);
        }

        return enumInstance;
    }
}