org.apache.flink.table.planner.functions.aggfunctions.RankAggFunction 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 org.apache.flink.table.planner.functions.aggfunctions;
import org.apache.flink.table.api.DataTypes;
import org.apache.flink.table.expressions.Expression;
import org.apache.flink.table.expressions.UnresolvedReferenceExpression;
import org.apache.flink.table.types.DataType;
import org.apache.flink.table.types.logical.LogicalType;
import org.apache.flink.table.types.utils.LogicalTypeDataTypeConverter;
import java.util.Arrays;
import static org.apache.flink.table.expressions.ApiExpressionUtils.unresolvedRef;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.and;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.equalTo;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.ifThenElse;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.literal;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.not;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.plus;
/** built-in rank aggregate function. */
public class RankAggFunction extends RankLikeAggFunctionBase {
private UnresolvedReferenceExpression currNumber = unresolvedRef("currNumber");
public RankAggFunction(LogicalType[] orderKeyTypes) {
super(orderKeyTypes);
}
@Override
public UnresolvedReferenceExpression[] aggBufferAttributes() {
UnresolvedReferenceExpression[] aggBufferAttrs =
new UnresolvedReferenceExpression[2 + lastValues.length];
aggBufferAttrs[0] = currNumber;
aggBufferAttrs[1] = sequence;
System.arraycopy(lastValues, 0, aggBufferAttrs, 2, lastValues.length);
return aggBufferAttrs;
}
@Override
public DataType[] getAggBufferTypes() {
DataType[] aggBufferTypes = new DataType[2 + orderKeyTypes.length];
aggBufferTypes[0] = DataTypes.BIGINT();
aggBufferTypes[1] = DataTypes.BIGINT();
System.arraycopy(
Arrays.stream(orderKeyTypes)
.map(LogicalTypeDataTypeConverter::toDataType)
.toArray(DataType[]::new),
0,
aggBufferTypes,
2,
orderKeyTypes.length);
return aggBufferTypes;
}
@Override
public Expression[] initialValuesExpressions() {
Expression[] initExpressions = new Expression[2 + orderKeyTypes.length];
// currNumber = 0L
initExpressions[0] = literal(0L);
// sequence = 0L
initExpressions[1] = literal(0L);
for (int i = 0; i < orderKeyTypes.length; ++i) {
// lastValue_i = init value
initExpressions[i + 2] = generateInitLiteral(orderKeyTypes[i]);
}
return initExpressions;
}
@Override
public Expression[] accumulateExpressions() {
Expression[] accExpressions = new Expression[2 + operands().length];
// currNumber = currNumber + 1
accExpressions[0] = plus(currNumber, literal(1L));
// sequence = if (lastValues equalTo orderKeys and sequence != 0) sequence else currNumber
accExpressions[1] =
ifThenElse(
and(orderKeyEqualsExpression(), not(equalTo(sequence, literal(0L)))),
sequence,
currNumber);
Expression[] operands = operands();
System.arraycopy(operands, 0, accExpressions, 2, operands.length);
return accExpressions;
}
}