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/*
 * 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 {@code ForeachAction} interface for performing an action on a {@link org.apache.kafka.streams.KeyValue key-value
 * pair}.
 * This is a stateless record-by-record operation, i.e, {@link #apply(Object, Object)} is invoked individually for each
 * record of a stream.
 * If stateful processing is required, consider using
 * {@link KStream#process(org.apache.kafka.streams.processor.api.ProcessorSupplier, String...) KStream#process(...)}.
 *
 * @param  key type
 * @param  value type
 *
 * @see KStream#foreach(ForeachAction)
 */
public interface ForeachAction {

    /**
     * Perform an action for each record of a stream.
     *
     * @param key
     *        the key of the record
     * @param value
     *        the value of the record
     */
    void apply(final K key, final V value);
}