Github user StefanRRichter commented on a diff in the pull request:
https://github.com/apache/flink/pull/6208#discussion_r198142470
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/jobmaster/slotpool/LocationPreferenceSchedulingStrategy.java
---
@@ -0,0 +1,119 @@
+/*
+ * 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.jobmaster.slotpool;
+
+import org.apache.flink.runtime.clusterframework.types.ResourceID;
+import org.apache.flink.runtime.clusterframework.types.SlotProfile;
+import org.apache.flink.runtime.jobmanager.scheduler.Locality;
+import org.apache.flink.runtime.jobmaster.SlotContext;
+import org.apache.flink.runtime.taskmanager.TaskManagerLocation;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.stream.Stream;
+
+/**
+ * Default {@link SchedulingStrategy} which tries to match a slot with its
location preferences.
+ */
+public class LocationPreferenceSchedulingStrategy implements
SchedulingStrategy {
+
+ private static final LocationPreferenceSchedulingStrategy INSTANCE =
new LocationPreferenceSchedulingStrategy();
+
+ /**
+ * Calculates the candidate's locality score.
+ */
+ private static final BiFunction<Integer, Integer, Integer>
LOCALITY_EVALUATION_FUNCTION = (localWeigh, hostLocalWeigh) -> localWeigh * 10
+ hostLocalWeigh;
+
+ LocationPreferenceSchedulingStrategy() {}
--- End diff --
can be `private`.
---
