1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.shardingsphere.sqlfederation.optimizer.statistic;
19
20 import org.apache.calcite.rel.RelCollation;
21 import org.apache.calcite.rel.RelDistribution;
22 import org.apache.calcite.rel.RelDistributionTraitDef;
23 import org.apache.calcite.rel.RelReferentialConstraint;
24 import org.apache.calcite.schema.Statistic;
25
26 import java.util.ArrayList;
27 import java.util.List;
28
29 /**
30 * SQL federation statistic.
31 */
32 public final class SQLFederationStatistic implements Statistic {
33
34 @Override
35 public List<RelReferentialConstraint> getReferentialConstraints() {
36 return new ArrayList<>();
37 }
38
39 @Override
40 public List<RelCollation> getCollations() {
41 return new ArrayList<>();
42 }
43
44 @Override
45 public RelDistribution getDistribution() {
46 return RelDistributionTraitDef.INSTANCE.getDefault();
47 }
48 }