    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
    015package org.apache.tapestry5.util;
    016
    017import org.apache.tapestry5.ValueEncoder;
    018import org.apache.tapestry5.ioc.internal.util.InternalUtils;
    019import 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 */
    024public 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 typeCoercer.coerce(value, String.class);
    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}