Github user StefanRRichter commented on a diff in the pull request:
https://github.com/apache/flink/pull/6186#discussion_r197503773
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/state/ttl/TtlAggregatingState.java
---
@@ -0,0 +1,80 @@
+/*
+ * 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.ttl;
+
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.runtime.state.internal.InternalAggregatingState;
+
+import java.util.Collection;
+
+/**
+ * This class wraps aggregating state with TTL logic.
+ *
+ * @param <K> The type of key the state is associated to
+ * @param <N> The type of the namespace
+ * @param <IN> Type of the value added to the state
+ * @param <ACC> The type of the accumulator (intermediate aggregate state).
+ * @param <OUT> Type of the value extracted from the state
+ *
+ */
+class TtlAggregatingState<K, N, IN, ACC, OUT>
+ extends AbstractTtlState<K, N, ACC, TtlValue<ACC>,
InternalAggregatingState<K, N, IN, TtlValue<ACC>, OUT>>
+ implements InternalAggregatingState<K, N, IN, ACC, OUT> {
+
+ TtlAggregatingState(
+ InternalAggregatingState<K, N, IN, TtlValue<ACC>, OUT>
originalState,
+ TtlConfig config,
+ TtlTimeProvider timeProvider,
+ TypeSerializer<ACC> valueSerializer,
+ TtlAggregateFunction<IN, ACC, OUT> aggregateFunction) {
+ super(originalState, config, timeProvider, valueSerializer);
+ aggregateFunction.stateClear = originalState::clear;
--- End diff --
Maybe it is better to pass a `TtlAggregateFunctionBuilder` and then supply
`stateClear` and `updater` before the object is created. I think then they can
also become immutable. Similar changes in the other states.
---
