/**
* 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 org.apache.tajo.engine.function.builtin;
import org.apache.tajo.catalog.CatalogUtil;
import org.apache.tajo.catalog.Column;
import org.apache.tajo.common.TajoDataTypes.DataType;
import org.apache.tajo.common.TajoDataTypes.Type;
import org.apache.tajo.datum.Datum;
import org.apache.tajo.datum.DatumFactory;
import org.apache.tajo.datum.Float8Datum;
import org.apache.tajo.datum.ProtobufDatum;
import org.apache.tajo.engine.function.AggFunction;
import org.apache.tajo.engine.function.FunctionContext;
import org.apache.tajo.storage.Tuple;
import static org.apache.tajo.InternalTypes.AvgLongProto;
public class AvgLong extends AggFunction<Float8Datum> {
public AvgLong() {
super(new Column[] {
new Column("val", Type.FLOAT8)
});
}
public AvgContext newContext() {
return new AvgContext();
}
@Override
public void eval(FunctionContext ctx, Tuple params) {
AvgContext avgCtx = (AvgContext) ctx;
avgCtx.sum += params.get(0).asInt8();
avgCtx.count++;
}
@Override
public void merge(FunctionContext ctx, Tuple part) {
AvgContext avgCtx = (AvgContext) ctx;
ProtobufDatum datum = (ProtobufDatum) part.get(0);
AvgLongProto proto = (AvgLongProto) datum.get();
avgCtx.sum += proto.getSum();
avgCtx.count += proto.getCount();
}
@Override
public Datum getPartialResult(FunctionContext ctx) {
AvgContext avgCtx = (AvgContext) ctx;
AvgLongProto.Builder builder = AvgLongProto.newBuilder();
builder.setSum(avgCtx.sum);
builder.setCount(avgCtx.count);
return new ProtobufDatum(builder.build());
}
@Override
public DataType getPartialResultType() {
return CatalogUtil.newDataType(Type.PROTOBUF, AvgLongProto.class.getName());
}
@Override
public Float8Datum terminate(FunctionContext ctx) {
AvgContext avgCtx = (AvgContext) ctx;
return DatumFactory.createFloat8((double) avgCtx.sum / avgCtx.count);
}
protected class AvgContext implements FunctionContext {
long sum;
long count;
}
}