Github user StefanRRichter commented on a diff in the pull request:
https://github.com/apache/flink/pull/5423#discussion_r167896900
--- Diff:
flink-runtime/src/test/java/org/apache/flink/runtime/io/network/api/writer/AbstractCollectingResultPartitionWriter.java
---
@@ -0,0 +1,100 @@
+/*
+ * 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.network.api.writer;
+
+import org.apache.flink.runtime.io.network.buffer.Buffer;
+import org.apache.flink.runtime.io.network.buffer.BufferConsumer;
+import org.apache.flink.runtime.io.network.buffer.BufferProvider;
+import org.apache.flink.runtime.io.network.partition.ResultPartitionID;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+import java.io.IOException;
+import java.util.ArrayDeque;
+
+import static org.apache.flink.util.Preconditions.checkNotNull;
+import static org.apache.flink.util.Preconditions.checkState;
+
+/**
+ * {@link ResultPartitionWriter} that collects output on the List.
+ */
+@ThreadSafe
+public abstract class AbstractCollectingResultPartitionWriter implements
ResultPartitionWriter {
+ private final BufferProvider bufferProvider;
+ private final ArrayDeque<BufferConsumer> bufferConsumers = new
ArrayDeque<>();
+
+ public AbstractCollectingResultPartitionWriter(BufferProvider
bufferProvider) {
+ this.bufferProvider = checkNotNull(bufferProvider);
+ }
+
+ @Override
+ public synchronized BufferProvider getBufferProvider() {
+ return bufferProvider;
+ }
+
+ @Override
+ public synchronized ResultPartitionID getPartitionId() {
+ return new ResultPartitionID();
--- End diff --
What is the intended effect of having this `synchronized`, looks like it
does nothing?
---
