flink-core/src/main/java/org/apache/flink/api/common/state/State.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.flink.api.common.state;

import org.apache.flink.annotation.PublicEvolving;

/**
 * Interface that different types of partitioned state must implement.
 *
 * <p>The state is only accessible by functions applied on a {@code KeyedStream}. The key is
 * automatically supplied by the system, so the function always sees the value mapped to the
 * key of the current element. That way, the system can handle stream and state partitioning
 * consistently together.
 */
@PublicEvolving
public interface State {

	/**
	 * Removes the value mapped under the current key.
	 */
	void clear();
}