/*
* Copyright 2013 Lei CHEN (raistlic@gmail.com)
*
* 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.raist.config;
import org.raist.common.codec.Codec;
import org.raist.common.codec.CodingException;
import java.util.HashMap;
import java.util.Map;
/**
* This is a factory class, which exports codecs of specified {@code enum} source
* type and the destination type of {@code String}.
*
* @author Lei.C (2013-11-04)
*/
public class EnumSerializer<E extends Enum<E>> implements Codec<E, String> {
/**
* This method exports a {@link Codec} instance of the specified {@code enum}
* type and the destination type of {@link String}.
*
* @throws IllegalArgumentException if the specified {@code enum} type is {@code null}.
*/
public static <E extends Enum<E>> EnumSerializer<E> of(Class<E> type) {
if( type == null )
throw new IllegalArgumentException("Specifiec enum type cannot be null.");
return new EnumSerializer(type);
}
/*
* The enum type reference, which provides the type context information at
* both compile time and run time, cannot be null.
*/
private final Class<E> type;
private final Map<String, E> map;
private EnumSerializer(Class<E> type) {
assert type != null;
this.type = type;
this.map = new HashMap<String, E>();
for(E e : type.getEnumConstants())
map.put(e.name(), e);
}
@Override
public boolean isValidSrc(E src) {
return true;
}
@Override
public String encode(E src) throws CodingException {
return src == null ? "" : src.name();
}
@Override
public boolean isValidDest(String dest) {
if( dest == null || dest.isEmpty() ) {
return true;
}
else {
return map.containsKey(dest);
}
}
@Override
public E decode(String dest) throws CodingException {
if( dest == null || dest.isEmpty() )
return null;
E result = map.get(dest);
if( result == null )
throw new CodingException(type.getSimpleName() + " not found: " + dest);
return result;
}
}