tapestry-core/src/main/java/org/apache/tapestry5/util/EnumValueEncoder.java

// Copyright 2007, 2008 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package org.apache.tapestry5.util;

import org.apache.tapestry5.ValueEncoder;
import static org.apache.tapestry5.ioc.internal.util.Defense.notNull;
import org.apache.tapestry5.ioc.internal.util.InternalUtils;

/**
 * A value encoder that can be used for aribrary Enum types. The enum name is stored as the client side value.
 */
public class EnumValueEncoder<E extends Enum<E>> implements ValueEncoder<E>
{
    private final Class<E> enumType;

    public EnumValueEncoder(final Class<E> enumType)
    {
        notNull(enumType, "enumType");

        this.enumType = enumType;
    }

    public String toClient(E value)
    {
        if (value == null) return null;

        return value.name();
    }

    @SuppressWarnings("unchecked")
    public E toValue(String clientValue)
    {
        if (InternalUtils.isBlank(clientValue)) return null;

        return Enum.valueOf(enumType, clientValue);
    }

}