cz.o2.proxima.direct.batch.BatchLogObserver Maven / Gradle / Ivy
/**
* Copyright 2017-2021 O2 Czech Republic, a.s.
*
* Licensed 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 cz.o2.proxima.direct.batch;
import cz.o2.proxima.annotations.Stable;
import cz.o2.proxima.storage.Partition;
import cz.o2.proxima.storage.StreamElement;
import cz.o2.proxima.time.WatermarkSupplier;
/**
* Batch observer of data. No commits needed.
*
* Implementations should override either of `onNext` methods.
*/
@Stable
public interface BatchLogObserver {
/** Context passed to {@link #onNext}. */
@Stable
interface OnNextContext extends WatermarkSupplier {
/**
* Retrieve partition for currently processed record.
*
* @return partition of currently processed record
*/
Partition getPartition();
/**
* Retrieve current watermark of the observe process
*
* @return watermark in milliseconds
*/
@Override
long getWatermark();
}
/**
* Read next data from the batch storage.
*
* @param element the retrieved data element
* @return {@code true} to continue processing, {@code false} otherwise
*/
default boolean onNext(StreamElement element) {
throw new UnsupportedOperationException("Please override either of `onNext` methods");
}
/**
* Read next data from the batch storage.
*
* @param element the retrieved data element
* @param context context of the data element
* @return {@code true} to continue processing, {@code false} otherwise
*/
default boolean onNext(StreamElement element, OnNextContext context) {
return onNext(element);
}
/** Signalled when the reading is finished. */
default void onCompleted() {}
/** Signalled when the reading is cancelled. */
default void onCancelled() {}
/**
* Signaled when reading error occurs.
*
* @param error error caught during processing
* @return {@code true} to restart processing from beginning {@code false} to stop processing
*/
default boolean onError(Throwable error) {
return false;
}
}