org.apache.flink.runtime.state.StateUtil Maven / Gradle / Ivy
/*
* 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.flink.runtime.state;
import org.apache.flink.util.LambdaUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.RunnableFuture;
/**
* Helpers for {@link StateObject} related code.
*/
public class StateUtil {
private static final Logger LOG = LoggerFactory.getLogger(StateUtil.class);
private StateUtil() {
throw new AssertionError();
}
/**
* Returns the size of a state object
*
* @param handle The handle to the retrieved state
*/
public static long getStateSize(StateObject handle) {
return handle == null ? 0 : handle.getStateSize();
}
/**
* Iterates through the passed state handles and calls discardState() on each handle that is not null. All
* occurring exceptions are suppressed and collected until the iteration is over and emitted as a single exception.
*
* @param handlesToDiscard State handles to discard. Passed iterable is allowed to deliver null values.
* @throws Exception exception that is a collection of all suppressed exceptions that were caught during iteration
*/
public static void bestEffortDiscardAllStateObjects(
Iterable handlesToDiscard) throws Exception {
LambdaUtil.applyToAllWhileSuppressingExceptions(handlesToDiscard, StateObject::discardState);
}
/**
* Discards the given state future by first trying to cancel it. If this is not possible, then
* the state object contained in the future is calculated and afterwards discarded.
*
* @param stateFuture to be discarded
* @throws Exception if the discard operation failed
*/
public static void discardStateFuture(Future stateFuture) throws Exception {
if (null != stateFuture) {
if (!stateFuture.cancel(true)) {
try {
// We attempt to get a result, in case the future completed before cancellation.
if (stateFuture instanceof RunnableFuture && !stateFuture.isDone()) {
((RunnableFuture) stateFuture).run();
}
StateObject stateObject = stateFuture.get();
if (null != stateObject) {
stateObject.discardState();
}
} catch (CancellationException | ExecutionException ex) {
LOG.debug("Cancelled execution of snapshot future runnable. Cancellation produced the following " +
"exception, which is expected an can be ignored.", ex);
}
}
}
}
}