org.apache.flink.table.runtime.functions.SubKeyedAggsHandleFunction Maven / Gradle / Ivy
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* 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
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*/
package org.apache.flink.table.runtime.functions;
import org.apache.flink.api.common.functions.Function;
import org.apache.flink.table.dataformat.BaseRow;
/**
* The base class for handling aggregate functions.
*
* The differences between {@link SubKeyedAggsHandleFunction} and {@link AggsHandleFunction}
* is that the {@code SubKeyedAggsHandleFunction} has namespace.
* @param type of namespace
*/
public interface SubKeyedAggsHandleFunction extends Function {
/**
* Initialization method for the function. It is called before the actual working methods.
*/
void open(ExecutionContext ctx) throws Exception;
/**
* Set the current accumulators (saved in a row) which contains the current
* aggregated results.
* @param accumulators current accumulators
*/
void setAccumulators(N namespace, BaseRow accumulators) throws Exception;
/**
* Accumulates the input values to the accumulators.
* @param inputRow input values bundled in a row
*/
void accumulate(BaseRow inputRow) throws Exception;
/**
* Retracts the input values from the accumulators.
* @param inputRow input values bundled in a row
*/
void retract(BaseRow inputRow) throws Exception;
/**
* Merges the other accumulators into current accumulators.
*
* @param otherAcc The other row of accumulators
*/
void merge(N namespace, BaseRow otherAcc) throws Exception;
/**
* Initializes the accumulators and save them to a accumulators row.
*
* @return a row of accumulators which contains the aggregated results
*/
BaseRow createAccumulators() throws Exception;
/**
* Gets the current accumulators (saved in a row) which contains the current
* aggregated results.
* @return the current accumulators
*/
BaseRow getAccumulators() throws Exception;
/**
* Gets the result of the aggregation from the current accumulators and
* namespace properties (like window start).
* @param namespace the namespace properties which should be calculated, such window start
* @return the final result (saved in a row) of the current accumulators.
*/
BaseRow getValue(N namespace) throws Exception;
/**
* Cleanup for the retired accumulators state.
*/
void cleanup(N namespace) throws Exception;
/**
* Tear-down method for this function. It can be used for clean up work.
* By default, this method does nothing.
*/
void close() throws Exception;
}