/*
 * 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.jdbi.v3.sqlobject.config;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import org.jdbi.v3.sqlobject.config.internal.KeyColumnImpl;

Configures the column to use for map keys, for SQL methods that return Map, or Guava's Multimap. 
Example:
@SqlQuery("select * from user")
@KeyColumn("id")
Map<Long, User> getUsersById();

/**
 * Configures the column to use for map keys, for SQL methods that return {@link java.util.Map}, or Guava's Multimap.
 * <p>Example:</p>
 * <pre>
 * &#64;SqlQuery("select * from user")
 * &#64;KeyColumn("id")
 * Map&lt;Long, User&gt; getUsersById();
 * </pre>
 */
@ConfiguringAnnotation(KeyColumnImpl.class)
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface KeyColumn {
    
Returns:
the column name to use for map keys./**
     * @return the column name to use for map keys.
     */
    String value();
}