HashKeyIsIdHashKeyExtractor.java

/*
 * Copyright © 2018 spring-data-dynamodb (https://github.com/prasanna0586/spring-data-dynamodb)
 *
 * 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.socialsignin.spring.data.dynamodb.repository.support;

import org.springframework.lang.NonNull;
import org.springframework.util.Assert;

/**
 * Hash key extractor for cases where the ID is also the hash key, requiring direct delegation to the ID.
 * @param <ID> the ID type which also serves as the hash key type
 * @author Prasanna Kumar Ramachandran
 */
public class HashKeyIsIdHashKeyExtractor<ID> implements HashKeyExtractor<ID, ID> {

    private final Class<ID> idAndHashKeyType;

    /**
     * Creates a new HashKeyIsIdHashKeyExtractor.
     * @param idAndHashKeyType the ID and hash key type
     */
    public HashKeyIsIdHashKeyExtractor(Class<ID> idAndHashKeyType) {
        this.idAndHashKeyType = idAndHashKeyType;
    }

    @NonNull
    @Override
    public ID getHashKey(@NonNull ID id) {
        Assert.isAssignable(idAndHashKeyType, id.getClass(),
                "Expected ID type to be the same as the return type of the hash key method ( " + idAndHashKeyType
                        + " ) : ");
        return id;
    }

}