792f606a64
Contains the cql3 grammer and supporting classes, which will be converted one by one. From commit bf599fb5b062cbcc652da78b7d699e7a01b949ad.
64 lines
2.0 KiB
Java
64 lines
2.0 KiB
Java
/*
|
|
* 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.cassandra.cql3.functions;
|
|
|
|
import java.nio.ByteBuffer;
|
|
import java.util.List;
|
|
|
|
import org.apache.cassandra.exceptions.InvalidRequestException;
|
|
|
|
/**
|
|
* Performs a calculation on a set of values and return a single value.
|
|
*/
|
|
public interface AggregateFunction extends Function
|
|
{
|
|
/**
|
|
* Creates a new <code>Aggregate</code> instance.
|
|
*
|
|
* @return a new <code>Aggregate</code> instance.
|
|
*/
|
|
public Aggregate newAggregate() throws InvalidRequestException;
|
|
|
|
/**
|
|
* An aggregation operation.
|
|
*/
|
|
interface Aggregate
|
|
{
|
|
/**
|
|
* Adds the specified input to this aggregate.
|
|
*
|
|
* @param protocolVersion native protocol version
|
|
* @param values the values to add to the aggregate.
|
|
*/
|
|
public void addInput(int protocolVersion, List<ByteBuffer> values) throws InvalidRequestException;
|
|
|
|
/**
|
|
* Computes and returns the aggregate current value.
|
|
*
|
|
* @param protocolVersion native protocol version
|
|
* @return the aggregate current value.
|
|
*/
|
|
public ByteBuffer compute(int protocolVersion) throws InvalidRequestException;
|
|
|
|
/**
|
|
* Reset this aggregate.
|
|
*/
|
|
public void reset();
|
|
}
|
|
}
|