com.datastax.driver.core.ContinuousPagingResult Maven / Gradle / Ivy
/*
* Copyright DataStax, Inc.
*
* This software can be used solely with DataStax Enterprise. Please consult the license at
* http://www.datastax.com/terms/datastax-dse-driver-license-terms
*/
package com.datastax.driver.core;
/**
* The result of a {@link ContinuousPagingSession#executeContinuously(Statement,
* ContinuousPagingOptions) synchronous continuous paging query}.
*
* A synchronous query uses asynchronous calls internally; this object handles the details of
* performing those calls, and assembling the results in an {@code Iterable}.
*
*
Note that {@link #iterator()} will always return the same iterator instance; in other word,
* this object is only iterable once, it is not possible to restart the iteration from the
* beginning.
*
*
This object is not thread safe, it should only be accessed from the thread that executed the
* query.
*/
public interface ContinuousPagingResult extends Iterable {
/** Returns the definition of the columns returned in this result set. */
ColumnDefinitions getColumnDefinitions();
/**
* Cancels the continuous query.
*
* The iteration will stop at the current page in the stream of results; if the server sends
* more pages after the cancellation (or if more pages were available in the driver's local
* cache), they will be discarded. Note however that there might still be rows available in the
* current page.
*
*
Therefore, if you plan to resume the iteration later, the correct procedure is:
*
*
* - invoke this method;
*
- keep iterating on this object until it doesn't return any more rows;
*
- retrieve the paging state with {@code getExecutionInfo().getPagingState()}, and reinject
* it in the statement to resume the iteration.
*
*/
void cancel();
/**
* Returns information on the execution of the query, and on the response frame corresponding to
* the current state of the iteration.
*
* The driver does not support query traces for continuous queries, the corresponding field
* will always be {@code null}.
*/
ExecutionInfo getExecutionInfo();
}