    001    // Copyright 2007, 2008, 2010, 2011 The Apache Software Foundation
    002    //
    003    // Licensed under the Apache License, Version 2.0 (the "License");
    004    // you may not use this file except in compliance with the License.
    005    // You may obtain a copy of the License at
    006    //
    007    // http://www.apache.org/licenses/LICENSE-2.0
    008    //
    009    // Unless required by applicable law or agreed to in writing, software
    010    // distributed under the License is distributed on an "AS IS" BASIS,
    011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012    // See the License for the specific language governing permissions and
    013    // limitations under the License.
    014
    015    package org.apache.tapestry5.util;
    016
    017    import org.apache.tapestry5.ValueEncoder;
    018    import org.apache.tapestry5.ioc.internal.util.InternalUtils;
    019    import org.apache.tapestry5.ioc.services.TypeCoercer;
    020
    021    /**
    022     * A value encoder that can be used for arbitrary Enum types. The enum name is stored as the client side value.
    023     */
    024    public class EnumValueEncoder<E extends Enum<E>> implements ValueEncoder<E>
    025    {
    026        private final TypeCoercer typeCoercer;
    027
    028        private final Class<E> enumType;
    029
    030        public EnumValueEncoder(TypeCoercer typeCoercer, final Class<E> enumType)
    031        {
    032            assert enumType != null;
    033
    034            this.typeCoercer = typeCoercer;
    035            this.enumType = enumType;
    036        }
    037
    038        public String toClient(E value)
    039        {
    040            if (value == null)
    041                return null;
    042
    043            return value.name();
    044        }
    045
    046        public E toValue(String clientValue)
    047        {
    048            if (InternalUtils.isBlank(clientValue))
    049                return null;
    050
    051            return typeCoercer.coerce(clientValue, enumType);
    052        }
    053
    054    }