Github user StefanRRichter commented on a diff in the pull request:
https://github.com/apache/flink/pull/6361#discussion_r203361200
--- Diff:
flink-end-to-end-tests/flink-stream-state-ttl-test/src/main/java/org/apache/flink/streaming/tests/verify/AbstractTtlStateVerifier.java
---
@@ -0,0 +1,132 @@
+/*
+ * 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.streaming.tests.verify;
+
+import org.apache.flink.api.common.state.State;
+import org.apache.flink.api.common.state.StateDescriptor;
+import org.apache.flink.api.common.state.StateTtlConfiguration;
+import org.apache.flink.api.common.time.Time;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.runtime.state.FunctionInitializationContext;
+
+import javax.annotation.Nonnull;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+import java.util.stream.IntStream;
+
+abstract class AbstractTtlStateVerifier<D extends StateDescriptor<S, SV>,
S extends State, SV, UV, GV>
+ implements TtlStateVerifier<UV, GV> {
+ static final Random RANDOM = new Random();
+
+ @Nonnull
+ final D stateDesc;
+
+ AbstractTtlStateVerifier(@Nonnull D stateDesc) {
+ this.stateDesc = stateDesc;
+ }
+
+ @Nonnull
+ static String randomString() {
+ StringBuilder sb = new StringBuilder();
+ IntStream.range(0, RANDOM.nextInt(14) + 2).forEach(i ->
sb.append(randomChar()));
+ return sb.toString();
+ }
+
+ private static char randomChar() {
+ char d = (char) ('0' + RANDOM.nextInt(9));
+ char l = (char) ('a' + RANDOM.nextInt(25));
+ return RANDOM.nextBoolean() ? d : l;
+ }
+
+ @SuppressWarnings("unchecked")
+ @Override
+ @Nonnull
+ public State createState(@Nonnull FunctionInitializationContext
context, @Nonnull StateTtlConfiguration ttlConfig) {
+ stateDesc.enableTimeToLive(ttlConfig);
+ return createState(context);
+ }
+
+ abstract State createState(FunctionInitializationContext context);
+
+ @SuppressWarnings("unchecked")
+ @Override
+ @Nonnull
+ public TypeSerializer<UV> getUpdateSerializer() {
+ return (TypeSerializer<UV>) stateDesc.getSerializer();
+ }
+
+ @SuppressWarnings("unchecked")
+ @Override
+ public GV get(@Nonnull State state) throws Exception {
+ return getInternal((S) state);
+ }
+
+ abstract GV getInternal(@Nonnull S state) throws Exception;
+
+ @SuppressWarnings("unchecked")
+ @Override
+ public void update(@Nonnull State state, Object update) throws
Exception {
+ updateInternal((S) state, (UV) update);
+ }
+
+ abstract void updateInternal(@Nonnull S state, UV update) throws
Exception;
+
+ @SuppressWarnings("unchecked")
+ @Override
+ public boolean verify(@Nonnull TtlVerificationContext<?, ?>
verificationContextRaw, @Nonnull Time precision) {
--- End diff --
I think you can get rid of handling wildcards `<?, ?>` and casting by
introducing the following method in `TtlVerifyFunction`:
```
private <A, B> void verify(TtlStateVerifier<A, B> verifier,
TtlVerificationContext<A, B> verificationContext) {
verifier.verify(verificationContext, precision);
}
```
and call it
```
verify(TtlStateVerifier.VERIFIERS_BY_NAME.get(value.getVerifierId()), new
TtlVerificationContext<>(prevValues, value));
```
---
