storm-client/src/jvm/org/apache/storm/state/StateEncoder.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.storm.state;

/**
 * The interface of State Encoder.
 */
public interface StateEncoder<K, V, KENCODEDT, VENCODEDT> {
    /**
     * Encode key.
     *
     * @param key the value of key (K type)
     * @return the encoded value of key (KENCODEDT type)
     */
    KENCODEDT encodeKey(K key);

    /**
     * Encode value.
     *
     * @param value the value of value (V type)
     * @return the encoded value of value (VENCODEDT type)
     */
    VENCODEDT encodeValue(V value);

    /**
     * Decode key.
     *
     * @param encodedKey the value of key (KRAW type)
     * @return the decoded value of key (K type)
     */
    K decodeKey(KENCODEDT encodedKey);

    /**
     * Decode value.
     *
     * @param encodedValue the value of key (VENCODEDT type)
     * @return the decoded value of key (V type)
     */
    V decodeValue(VENCODEDT encodedValue);

    /**
     * Get the tombstone value (deletion mark).
     *
     * @return the tomestone value (VENCODEDT type)
     */
    VENCODEDT getTombstoneValue();
}