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https://issues.apache.org/jira/browse/FLINK-7619?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16176243#comment-16176243
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ASF GitHub Bot commented on FLINK-7619:
---------------------------------------
Github user aljoscha commented on a diff in the pull request:
https://github.com/apache/flink/pull/4671#discussion_r140458424
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/io/async/AbstractAsyncCallableWithResources.java
---
@@ -0,0 +1,194 @@
+/*
+ * 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.io.async;
+
+import org.apache.flink.util.ExceptionUtils;
+
+import java.io.IOException;
+
+/**
+ * The abstract class encapsulates the lifecycle and execution strategy
for asynchronous operations that use resources.
+ *
+ * @param <V> return type of the asynchronous call.
+ */
+public abstract class AbstractAsyncCallableWithResources<V> implements
StoppableCallbackCallable<V> {
+
+ /** Tracks if the stop method was called on this object. */
+ private volatile boolean stopped;
+
+ /** Tracks if call method was executed (only before stop calls). */
+ private volatile boolean called;
+
+ /** Stores a collected exception if there was on during stop. */
+ private volatile Exception stopException;
+
+ public AbstractAsyncCallableWithResources() {
+ this.stopped = false;
+ this.called = false;
+ }
+
+ /**
+ * This method implements the strategy for the actual IO operation:
+ * <p>
+ * 1) Acquire resources asynchronously and atomically w.r.t stopping.
+ * 2) Performs the operation
+ * 3) Releases resources.
+ *
+ * @return Result of the IO operation, e.g. a deserialized object.
+ * @throws Exception exception that happened during the call.
+ */
+ @Override
+ public V call() throws Exception {
--- End diff --
Should this be final?
> Improve abstraction in AbstractAsyncIOCallable to better fit
> ------------------------------------------------------------
>
> Key: FLINK-7619
> URL: https://issues.apache.org/jira/browse/FLINK-7619
> Project: Flink
> Issue Type: Improvement
> Components: State Backends, Checkpointing
> Reporter: Stefan Richter
> Assignee: Stefan Richter
> Priority: Minor
>
> The abstraction of AbstractAsyncIOCallable does not fit to well with todays
> needs in checkpointing backends. Originally, backends were assumed to only
> open one stream that is managed by the abstraction. In fact, concrete
> implementations always extended that in practise. We can redo this in a way
> that more resources can be managed by the abstraction.
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