org.apache.kafka.streams.query.FailureReason Maven / Gradle / Ivy

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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.query;


import org.apache.kafka.common.annotation.InterfaceStability.Evolving;

/**
 * This enumeration type captures the various top-level reasons that a particular
 * partition of a store would fail to execute a query. Stores should generally
 * respond with a failure message instead of throwing an exception.
 * 
 * Intended to be used in {@link QueryResult#forFailure(FailureReason, String)}.
 */
@Evolving
public enum FailureReason {
    /**
     * Failure indicating that the store doesn't know how to handle the given query.
     */
    UNKNOWN_QUERY_TYPE,

    /**
     * The query required to execute on an active task (via {@link StateQueryRequest#requireActive()}),
     * but while executing the query, the task was either a Standby task, or it was an Active task
     * not in the RUNNING state. The failure message will contain the reason for the failure.
     * 
     * The caller should either try again later or try a different replica.
     */
    NOT_ACTIVE,

    /**
     * Failure indicating that the store partition is not (yet) up to the desired bound. The caller
     * should either try again later or try a different replica.
     */
    NOT_UP_TO_BOUND,

    /**
     * Failure indicating that the requested store partition is not present on the local
     * KafkaStreams instance. It may have been migrated to another instance during a rebalance. The
     * caller is recommended to try a different replica.
     */
    NOT_PRESENT,

    /**
     * The requested store partition does not exist at all. For example, partition 4 was requested,
     * but the store in question only has 4 partitions (0 through 3).
     */
    DOES_NOT_EXIST,

    /**
     * The store that handled the query got an exception during query execution. The message
     * will contain the exception details. Depending on the nature of the exception, the caller
     * may be able to retry this instance or may need to try a different instance.
     */
    STORE_EXCEPTION
}