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/*
 * Copyright (C) 2012-2016 DuyHai DOAN
 *
 * 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 info.archinnov.achilles.annotations;

import java.lang.annotation.*;

/**

 * Transform a custom Java type into one of native types supported by the Java driver
 * 


 * The Codec class provided should implement the {@link info.archinnov.achilles.type.codec.Codec} interface.
 * 
 * 

 * 

 * Let's consider the following codec transforming a Long to a String
 * 

 * public class LongToString implements Codec<Long,String> {
 * {@literal @}Override
 * public Class sourceType() {
 * return Long.class;
 * }

 * {@literal @}Override
 * public Class targetType() {
 * return String.class;
 * }

 * {@literal @}Override
 * public String encode(Long fromJava) throws AchillesTranscodingException {
 * return fromJava.toString();
 * }

 * {@literal @}Override
 * public Long decode(String fromCassandra) throws AchillesTranscodingException {
 * return Long.parseLong(fromCassandra);
 * }
 * }
 * 
 * 

 * Example of simple Long type to String type transformation
 * 

 * {@literal @}Column
 * {@literal @}Codec(LongToString.class)
 * private Long longToString;

 * 
 * 

 * Example of List<Long> to List<String> transformation
 * 

 * {@literal @}Column
 * private List<{@literal @}Codec(LongToString.class) Long> listOfLongToString;

 * 

 * 

 * Example of Set<Long> to Set<String> transformation
 * 

 * {@literal @}Column
 * private Set<{@literal @}Codec(LongToString.class) Long> setOfLongToString;

 * 

 * 

 * Example of key Map transformation: Map<Long, Double> to Map<String, Double>
 * 

 * {@literal @}Column
 * private Map<{@literal @}Codec(LongToString.class) Long, Double> mapKeyTransformation;

 * 

 * 

 * Example of value Map transformation: Map<Integer, Long> to Map<Integer, String>
 * 

 * {@literal @}Column
 * private Map<Integer,{@literal @}Codec(LongToString.class)Long > mapValueTransformation;

 * 

 * 

 * Example of key/value Map transformation: Map<Long, Long> to Map<String, String>
 * 

 * {@literal @}Column
 * private Map<{@literal @}Codec(LongToString.class) Long, {@literal @}Codec(LongToString.class) Long > mapKeyValueTransformation;
 * 

 * 

 * You can also have nested usage of {@literal @}Codec. The nesting level can be arbitrary and does not matter
 * 


 * 2-levels nesting
 * 
 * {@literal @}Column
 * private Tuple2<String, Map<Integer, {@literal @}Codec(LongToString.class) Long>> nested1Level
 * 
 * 


 * 3-levels nesting
 * 
 * {@literal @}Column
 * private Tuple2<String, Map<Integer, List<{@literal @}Codec(LongToString.class) Long>>> nested2Level
 * 
 * 
 */
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD, ElementType.TYPE_USE, ElementType.TYPE_PARAMETER})
@Documented
public @interface Codec {

    /**
     * Codec Implementation class. The provided Codec class should implement the {@link info.archinnov.achilles.type.codec.Codec} interface.
     */
    Class value();
}