org.apache.spark.sql.sources.v2.reader.streaming.MicroBatchReader 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.spark.sql.sources.v2.reader.streaming;
import org.apache.spark.annotation.InterfaceStability;
import org.apache.spark.sql.sources.v2.reader.DataSourceReader;
import org.apache.spark.sql.execution.streaming.BaseStreamingSource;
import java.util.Optional;
/**
* A mix-in interface for {@link DataSourceReader}. Data source readers can implement this
* interface to indicate they allow micro-batch streaming reads.
*
* Note: This class currently extends {@link BaseStreamingSource} to maintain compatibility with
* DataSource V1 APIs. This extension will be removed once we get rid of V1 completely.
*/
@InterfaceStability.Evolving
public interface MicroBatchReader extends DataSourceReader, BaseStreamingSource {
/**
* Set the desired offset range for reader factories created from this reader. Reader factories
* will generate only data within (`start`, `end`]; that is, from the first record after `start`
* to the record with offset `end`.
*
* @param start The initial offset to scan from. If not specified, scan from an
* implementation-specified start point, such as the earliest available record.
* @param end The last offset to include in the scan. If not specified, scan up to an
* implementation-defined endpoint, such as the last available offset
* or the start offset plus a target batch size.
*/
void setOffsetRange(Optional start, Optional end);
/**
* Returns the specified (if explicitly set through setOffsetRange) or inferred start offset
* for this reader.
*
* @throws IllegalStateException if setOffsetRange has not been called
*/
Offset getStartOffset();
/**
* Return the specified (if explicitly set through setOffsetRange) or inferred end offset
* for this reader.
*
* @throws IllegalStateException if setOffsetRange has not been called
*/
Offset getEndOffset();
/**
* Deserialize a JSON string into an Offset of the implementation-defined offset type.
* @throws IllegalArgumentException if the JSON does not encode a valid offset for this reader
*/
Offset deserializeOffset(String json);
/**
* Informs the source that Spark has completed processing all data for offsets less than or
* equal to `end` and will only request offsets greater than `end` in the future.
*/
void commit(Offset end);
}