com.datastax.dse.driver.api.core.cql.continuous.ContinuousAsyncResultSet Maven / Gradle / Ivy
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* 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
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* See the License for the specific language governing permissions and
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package com.datastax.dse.driver.api.core.cql.continuous;
import com.datastax.oss.driver.api.core.AsyncPagingIterable;
import com.datastax.oss.driver.api.core.cql.ExecutionInfo;
import com.datastax.oss.driver.api.core.cql.Row;
import com.datastax.oss.driver.api.core.cql.Statement;
import edu.umd.cs.findbugs.annotations.NonNull;
import java.nio.ByteBuffer;
import java.util.concurrent.CancellationException;
/**
* The result of an {@linkplain ContinuousSession#executeContinuouslyAsync(Statement) asynchronous
* continuous paging query}.
*
* DSE replies to a continuous query with a stream of response frames. There is one instance of
* this class for each frame.
*/
public interface ContinuousAsyncResultSet
extends AsyncPagingIterable {
/** Returns the current page's number. Pages are numbered starting from 1. */
int pageNumber();
/**
* Cancels the continuous query.
*
* There might still be rows available in the {@linkplain #currentPage() current page} after
* the cancellation; these rows can be retrieved normally.
*
*
Also, there might be more pages available in the driver's local page cache after the
* cancellation; these extra pages will be discarded.
*
*
Therefore, if you plan to resume the iteration later, the correct procedure is as follows:
*
*
* - Cancel the operation by invoking this method, or by cancelling the {@linkplain
* #fetchNextPage() next page's future};
*
- Keep iterating on the current page until it doesn't return any more rows;
*
- Retrieve the paging state with {@link #getExecutionInfo()
* getExecutionInfo().getPagingState()};
*
- {@linkplain Statement#setPagingState(ByteBuffer) Re-inject the paging state} in the
* statement;
*
- Resume the operation by invoking {@link
* ContinuousSession#executeContinuouslyAsync(Statement) executeContinuouslyAsync} again.
*
*
* After a cancellation, futures returned by {@link #fetchNextPage()} that are not yet complete
* will always complete exceptionally by throwing a {@link CancellationException}, even if
* they were obtained before the cancellation.
*/
void cancel();
/**
* {@inheritDoc}
*
* Note: because the driver does not support query traces for continuous queries, {@link
* ExecutionInfo#getTracingId()} will always be {@code null}.
*/
@NonNull
@Override
ExecutionInfo getExecutionInfo();
}