/**
* Licensed to Odiago, Inc. under one or more contributor license
* agreements. See the NOTICE.txt file distributed with this work for
* additional information regarding copyright ownership. Odiago, Inc.
* 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.odiago.flumebase.exec.builtins;
import java.util.Collections;
import java.util.List;
import com.odiago.flumebase.exec.Bucket;
import com.odiago.flumebase.lang.AggregateFunc;
import com.odiago.flumebase.lang.Type;
import com.odiago.flumebase.lang.UniversalType;
/**
* Return the min non-null value in a column.
*/
@SuppressWarnings("rawtypes")
public class min extends AggregateFunc<Comparable> {
private UniversalType mArgType;
public min() {
// Argument may have any input type.
mArgType = new UniversalType("'a");
mArgType.addConstraint(Type.getNullable(Type.TypeName.TYPECLASS_COMPARABLE));
}
@Override
public void addToBucket(Object arg, Bucket<Comparable> bucket, Type type) {
assert type.isComparable();
Comparable comparableArg = (Comparable) arg;
if (null != comparableArg) {
Object curMin = bucket.getState();
if (curMin == null || comparableArg.compareTo(curMin) < 0) {
// No currently defined min, or we just exceeded the observed min. Use this.
bucket.setState(comparableArg);
}
}
}
@Override
public Object finishWindow(Iterable<Bucket<Comparable>> buckets, Type type) {
Comparable curMin = null;
for (Bucket<Comparable> bucket : buckets) {
Comparable state = bucket.getState();
if (curMin == null || (null != state && state.compareTo(curMin) < 0)) {
curMin = state;
}
}
return curMin;
}
@Override
public Type getReturnType() {
return mArgType; // Return type is the same as our argument.
}
@Override
public List<Type> getArgumentTypes() {
return Collections.singletonList((Type) mArgType);
}
}