com.hazelcast.org.apache.calcite.rel.RelCollation Maven / Gradle / Ivy
/*
* 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 com.hazelcast.org.apache.calcite.rel;
import com.hazelcast.org.apache.calcite.plan.RelMultipleTrait;
import com.hazelcast.org.apache.calcite.util.ImmutableIntList;
import java.util.List;
/**
* Description of the physical ordering of a relational expression.
*
* An ordering consists of a list of one or more column ordinals and the
* direction of the ordering.
*/
public interface RelCollation extends RelMultipleTrait {
//~ Methods ----------------------------------------------------------------
/**
* Returns the ordinals and directions of the columns in this ordering.
*/
List getFieldCollations();
/**
* Returns the ordinals of the key columns.
*/
default ImmutableIntList getKeys() {
final List collations = getFieldCollations();
final int size = collations.size();
final int[] keys = new int[size];
for (int i = 0; i < size; i++) {
keys[i] = collations.get(i).getFieldIndex();
}
return ImmutableIntList.of(keys);
}
}