// 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.ioc.internal.util.CollectionFactory;

 import org.apache.tapestry5.ioc.internal.util.InternalUtils;

 import org.apache.tapestry5.ioc.services.Coercion;

 import java.util.Map;

 /**

  * A {@link org.apache.tapestry5.ioc.services.Coercion} for converting strings into an instance of a particular

  * enumerated type. The {@link Enum#name() name} is used as the key to identify the enum instance, in a case-insensitive

  * fashion.

  *

  * @param <T> the type of enumeration

  */

 public final class StringToEnumCoercion<T extends Enum> implements Coercion<String, T>

 {

     private final Class<T> enumClass;

     private final Map<String, T> stringToEnum = CollectionFactory.newCaseInsensitiveMap();

     public StringToEnumCoercion(Class<T> enumClass)

     {

         this(enumClass, enumClass.getEnumConstants());

     }

     public StringToEnumCoercion(Class<T> enumClass, T... values)

     {

         this.enumClass = enumClass;

         for (T value : values)

             stringToEnum.put(value.name(), value);

     }

     public T coerce(String input)

     {

         if (InternalUtils.isBlank(input))

             return null;

         T result = stringToEnum.get(input);

         if (result == null)

             throw new RuntimeException(PublicUtilMessages.missingEnumValue(

                     input,

                     enumClass,

                     stringToEnum.keySet()));

         return result;

     }

     public static <T extends Enum> StringToEnumCoercion<T> create(Class<T> enumClass)

     {

         return new StringToEnumCoercion<T>(enumClass);

     }

 }