Github user mcvsubbu commented on a diff in the pull request:
https://github.com/apache/helix/pull/145#discussion_r176489075
--- Diff:
helix-core/src/main/java/org/apache/helix/api/rebalancer/constraint/AbstractRebalanceSoftConstraint.java
---
@@ -0,0 +1,56 @@
+package org.apache.helix.api.rebalancer.constraint;
+
+/*
+ * 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.
+ */
+
+import org.apache.helix.controller.common.ResourcesStateMap;
+
+import java.util.Map;
+
+public abstract class AbstractRebalanceSoftConstraint {
+ private static int DEFAULT_IMPORTANCE = 1;
+ protected int _importance = DEFAULT_IMPORTANCE;
+
+ /**
+ * Evaluate how the given assignment fits the constraint.
+ * @param resource Target resource
+ * @param proposedAssignment Map of <PartitionName, lists of possible
ParticipantName>
+ * @return Evaluation about the assignment. Larger number means better
fit under this constraint.
+ */
+ public abstract Map<String, int[]> evaluate(String resource,
+ Map<String, String[]> proposedAssignment);
+
+ /**
+ * @return The soft constraint's importance that will be used to compare
with other soft constraint results.
+ * Aggregated evaluation score = SUM(constraint_evaluation * importance).
+ */
+ public int getConstraintImportance() {
--- End diff --
Good to add that larger means more important. I am still not fully
convinced the importance is the right name for this. Maybe @kishoreg has other
ideas? I mentioned importance in a comment because I got confused between the
usage of the word weight in various places.
---
