/**
* 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 count of non-null values in a column.
*/
public class count extends AggregateFunc<Integer> {
private UniversalType mArgType;
public count() {
// Argument may have any input type.
mArgType = new UniversalType("'a");
mArgType.addConstraint(Type.getNullable(Type.TypeName.TYPECLASS_ANY));
}
private Integer getState(Bucket<Integer> bucket) {
Integer state = bucket.getState();
if (null == state) {
state = Integer.valueOf(0);
}
return state;
}
@Override
public void addToBucket(Object arg, Bucket<Integer> bucket, Type type) {
assert type.equals(Type.getPrimitive(Type.TypeName.INT));
if (null != arg) {
Integer state = getState(bucket);
int val = 0;
if (null != state) {
val = state.intValue();
}
val++; // Non-null item in bucket increments state.
bucket.setState(Integer.valueOf(val));
}
}
@Override
public Object finishWindow(Iterable<Bucket<Integer>> buckets, Type type) {
int total = 0;
for (Bucket<Integer> bucket : buckets) {
Integer state = bucket.getState();
if (null != state) {
total += state.intValue();
}
}
return Integer.valueOf(total);
}
@Override
public Type getReturnType() {
return Type.getPrimitive(Type.TypeName.INT);
}
@Override
public List<Type> getArgumentTypes() {
return Collections.singletonList((Type) mArgType);
}
}