org.apache.kafka.connect.storage.OffsetStorageReader Maven / Gradle / Ivy
/*
* 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.connect.storage;
import java.util.Collection;
import java.util.Map;
/**
*
* OffsetStorageReader provides access to the offset storage used by sources. This can be used by
* connectors to determine offsets to start consuming data from. This is most commonly used during
* initialization of a task, but can also be used during runtime, e.g. when reconfiguring a task.
*
*
* Offsets are always defined as Maps of Strings to primitive types, i.e. all types supported by
* {@link org.apache.kafka.connect.data.Schema} other than Array, Map, and Struct.
*
*/
public interface OffsetStorageReader {
/**
* Get the offset for the specified partition. If the data isn't already available locally, this
* gets it from the backing store, which may require some network round trips.
*
* @param partition object uniquely identifying the partition of data
* @return object uniquely identifying the offset in the partition of data
*/
Map offset(Map partition);
/**
*
* Get a set of offsets for the specified partition identifiers. This may be more efficient
* than calling {@link #offset(Map)} repeatedly.
*
*
* Note that when errors occur, this method omits the associated data and tries to return as
* many of the requested values as possible. This allows a task that's managing many partitions to
* still proceed with any available data. Therefore, implementations should take care to check
* that the data is actually available in the returned response. The only case when an
* exception will be thrown is if the entire request failed, e.g. because the underlying
* storage was unavailable.
*
*
* @param partitions set of identifiers for partitions of data
* @return a map of partition identifiers to decoded offsets
*/
Map, Map> offsets(Collection> partitions);
}