streams/src/main/java/org/apache/kafka/streams/kstream/ValueJoiner.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.kafka.streams.kstream;

/**
 * The {@link ValueJoiner} interface for joining two values into a new value.
 *
 * @param <V1>  first value type
 * @param <V2>  second value type
 * @param <R>   joined value type
 */
public interface ValueJoiner<V1, V2, R> {

    /**
     * Return a joined value consisting of {@code value1} and {@code value2}.
     *
     * @param value1  the first value for joining
     * @param value2  the second value for joining
     * @return        the joined value
     */
    R apply(V1 value1, V2 value2);
}