com.hazelcast.org.apache.calcite.adapter.enumerable.SourceSorter 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.adapter.enumerable;
import com.hazelcast.org.apache.calcite.linq4j.Linq4j;
import com.hazelcast.org.apache.calcite.linq4j.function.Function1;
import com.hazelcast.org.apache.calcite.linq4j.function.Function2;
import java.util.Comparator;
import java.util.List;
/**
* Helper that combines the sorting process and accumulating process against the
* aggregate execution, used with {@link LazyAggregateLambdaFactory}.
*
* @param Type of the accumulator
* @param Type of the enumerable input source
* @param Type of the sort key
*/
public class SourceSorter
implements LazyAggregateLambdaFactory.LazyAccumulator {
private final Function2 accumulatorAdder;
private final Function1 keySelector;
private final Comparator comparator;
public SourceSorter(
Function2 accumulatorAdder,
Function1 keySelector,
Comparator comparator) {
this.accumulatorAdder = accumulatorAdder;
this.keySelector = keySelector;
this.comparator = comparator;
}
@Override public void accumulate(Iterable sourceIterable,
TAccumulate accumulator) {
sortAndAccumulate(sourceIterable, accumulator);
}
private void sortAndAccumulate(Iterable sourceIterable,
TAccumulate accumulator) {
List sorted = Linq4j.asEnumerable(sourceIterable)
.orderBy(keySelector, comparator)
.toList();
TAccumulate accumulator1 = accumulator;
for (TSource source : sorted) {
accumulator1 = accumulatorAdder.apply(accumulator1, source);
}
}
}