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/*
* Copyright DataStax, Inc.
*
* 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 com.datastax.driver.core;
import com.datastax.driver.core.exceptions.NoHostAvailableException;
import com.datastax.driver.core.exceptions.QueryExecutionException;
import com.datastax.driver.core.exceptions.QueryValidationException;
import com.google.common.util.concurrent.ListenableFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
/**
* A future on a {@link ResultSet}.
*
* Note that this class implements Guava's {@code
* ListenableFuture} and can so be used with Guava's future utilities.
*/
public interface ResultSetFuture extends ListenableFuture {
/**
* Waits for the query to return and return its result.
*
* This method is usually more convenient than {@link #get} because it:
*
*
* - Waits for the result uninterruptibly, and so doesn't throw {@link InterruptedException}.
*
- Returns meaningful exceptions, instead of having to deal with ExecutionException.
*
*
* As such, it is the preferred way to get the future result.
*
* @return the query result set.
* @throws NoHostAvailableException if no host in the cluster can be contacted successfully to
* execute this query.
* @throws QueryExecutionException if the query triggered an execution exception, that is an
* exception thrown by Cassandra when it cannot execute the query with the requested
* consistency level successfully.
* @throws QueryValidationException if the query is invalid (syntax error, unauthorized or any
* other validation problem).
*/
public ResultSet getUninterruptibly();
/**
* Waits for the provided time for the query to return and return its result if available.
*
* This method is usually more convenient than {@link #get} because it:
*
*
* - Waits for the result uninterruptibly, and so doesn't throw {@link InterruptedException}.
*
- Returns meaningful exceptions, instead of having to deal with ExecutionException.
*
*
* As such, it is the preferred way to get the future result.
*
* @param timeout the time to wait for the query to return.
* @param unit the unit for {@code timeout}.
* @return the query result set.
* @throws NoHostAvailableException if no host in the cluster can be contacted successfully to
* execute this query.
* @throws QueryExecutionException if the query triggered an execution exception, that is an
* exception thrown by Cassandra when it cannot execute the query with the requested
* consistency level successfully.
* @throws QueryValidationException if the query if invalid (syntax error, unauthorized or any
* other validation problem).
* @throws TimeoutException if the wait timed out (Note that this is different from a Cassandra
* timeout, which is a {@code QueryExecutionException}).
*/
public ResultSet getUninterruptibly(long timeout, TimeUnit unit) throws TimeoutException;
/**
* Attempts to cancel the execution of the request corresponding to this future. This attempt will
* fail if the request has already returned.
*
* Please note that this only cancel the request driver side, but nothing is done to interrupt
* the execution of the request Cassandra side (and that even if {@code mayInterruptIfRunning} is
* true) since Cassandra does not support such interruption.
*
*
This method can be used to ensure no more work is performed driver side (which, while it
* doesn't include stopping a request already submitted to a Cassandra node, may include not
* retrying another Cassandra host on failure/timeout) if the ResultSet is not going to be
* retried. Typically, the code to wait for a request result for a maximum of 1 second could look
* like:
*
*
* ResultSetFuture future = session.executeAsync(...some query...);
* try {
* ResultSet result = future.get(1, TimeUnit.SECONDS);
* ... process result ...
* } catch (TimeoutException e) {
* future.cancel(true); // Ensure any resource used by this query driver
* // side is released immediately
* ... handle timeout ...
* }
*
*
* @param mayInterruptIfRunning the value of this parameter is currently ignored.
* @return {@code false} if the future could not be cancelled (it has already completed normally);
* {@code true} otherwise.
*/
@Override
public boolean cancel(boolean mayInterruptIfRunning);
}