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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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.*;
import com.google.common.base.Objects;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.datastax.driver.core.TypeCodec;
import org.apache.cassandra.db.marshal.AbstractType;
import org.apache.cassandra.exceptions.InvalidRequestException;
import org.apache.cassandra.schema.Functions;
import org.apache.cassandra.tracing.Tracing;
import org.apache.cassandra.transport.ProtocolVersion;
/**
* Base class for user-defined-aggregates.
*/
public class UDAggregate extends AbstractFunction implements AggregateFunction
{
protected static final Logger logger = LoggerFactory.getLogger(UDAggregate.class);
private final AbstractType stateType;
private final TypeCodec stateTypeCodec;
private final TypeCodec returnTypeCodec;
protected final ByteBuffer initcond;
private final ScalarFunction stateFunction;
private final ScalarFunction finalFunction;
public UDAggregate(FunctionName name,
List> argTypes,
AbstractType returnType,
ScalarFunction stateFunc,
ScalarFunction finalFunc,
ByteBuffer initcond)
{
super(name, argTypes, returnType);
this.stateFunction = stateFunc;
this.finalFunction = finalFunc;
this.stateType = stateFunc != null ? stateFunc.returnType() : null;
this.stateTypeCodec = stateType != null ? UDHelper.codecFor(UDHelper.driverType(stateType)) : null;
this.returnTypeCodec = returnType != null ? UDHelper.codecFor(UDHelper.driverType(returnType)) : null;
this.initcond = initcond;
}
public static UDAggregate create(Functions functions,
FunctionName name,
List> argTypes,
AbstractType returnType,
FunctionName stateFunc,
FunctionName finalFunc,
AbstractType stateType,
ByteBuffer initcond)
throws InvalidRequestException
{
List> stateTypes = new ArrayList<>(argTypes.size() + 1);
stateTypes.add(stateType);
stateTypes.addAll(argTypes);
List> finalTypes = Collections.singletonList(stateType);
return new UDAggregate(name,
argTypes,
returnType,
resolveScalar(functions, name, stateFunc, stateTypes),
finalFunc != null ? resolveScalar(functions, name, finalFunc, finalTypes) : null,
initcond);
}
public static UDAggregate createBroken(FunctionName name,
List> argTypes,
AbstractType returnType,
ByteBuffer initcond,
InvalidRequestException reason)
{
return new UDAggregate(name, argTypes, returnType, null, null, initcond)
{
public Aggregate newAggregate() throws InvalidRequestException
{
throw new InvalidRequestException(String.format("Aggregate '%s' exists but hasn't been loaded successfully for the following reason: %s. "
+ "Please see the server log for more details",
this,
reason.getMessage()));
}
};
}
public boolean hasReferenceTo(Function function)
{
return stateFunction == function || finalFunction == function;
}
@Override
public void addFunctionsTo(List functions)
{
functions.add(this);
if (stateFunction != null)
{
stateFunction.addFunctionsTo(functions);
if (finalFunction != null)
finalFunction.addFunctionsTo(functions);
}
}
public boolean isAggregate()
{
return true;
}
public boolean isNative()
{
return false;
}
public ScalarFunction stateFunction()
{
return stateFunction;
}
public ScalarFunction finalFunction()
{
return finalFunction;
}
public ByteBuffer initialCondition()
{
return initcond;
}
public AbstractType stateType()
{
return stateType;
}
public Aggregate newAggregate() throws InvalidRequestException
{
return new Aggregate()
{
private long stateFunctionCount;
private long stateFunctionDuration;
private Object state;
private boolean needsInit = true;
public void addInput(ProtocolVersion protocolVersion, List values) throws InvalidRequestException
{
maybeInit(protocolVersion);
long startTime = System.nanoTime();
stateFunctionCount++;
if (stateFunction instanceof UDFunction)
{
UDFunction udf = (UDFunction)stateFunction;
if (udf.isCallableWrtNullable(values))
state = udf.executeForAggregate(protocolVersion, state, values);
}
else
{
throw new UnsupportedOperationException("UDAs only support UDFs");
}
stateFunctionDuration += (System.nanoTime() - startTime) / 1000;
}
private void maybeInit(ProtocolVersion protocolVersion)
{
if (needsInit)
{
state = initcond != null ? UDHelper.deserialize(stateTypeCodec, protocolVersion, initcond.duplicate()) : null;
stateFunctionDuration = 0;
stateFunctionCount = 0;
needsInit = false;
}
}
public ByteBuffer compute(ProtocolVersion protocolVersion) throws InvalidRequestException
{
maybeInit(protocolVersion);
// final function is traced in UDFunction
Tracing.trace("Executed UDA {}: {} call(s) to state function {} in {}\u03bcs", name(), stateFunctionCount, stateFunction.name(), stateFunctionDuration);
if (finalFunction == null)
return UDFunction.decompose(stateTypeCodec, protocolVersion, state);
if (finalFunction instanceof UDFunction)
{
UDFunction udf = (UDFunction)finalFunction;
Object result = udf.executeForAggregate(protocolVersion, state, Collections.emptyList());
return UDFunction.decompose(returnTypeCodec, protocolVersion, result);
}
throw new UnsupportedOperationException("UDAs only support UDFs");
}
public void reset()
{
needsInit = true;
}
};
}
private static ScalarFunction resolveScalar(Functions functions, FunctionName aName, FunctionName fName, List> argTypes) throws InvalidRequestException
{
Optional fun = functions.find(fName, argTypes);
if (!fun.isPresent())
throw new InvalidRequestException(String.format("Referenced state function '%s %s' for aggregate '%s' does not exist",
fName,
Arrays.toString(UDHelper.driverTypes(argTypes)),
aName));
if (!(fun.get() instanceof ScalarFunction))
throw new InvalidRequestException(String.format("Referenced state function '%s %s' for aggregate '%s' is not a scalar function",
fName,
Arrays.toString(UDHelper.driverTypes(argTypes)),
aName));
return (ScalarFunction) fun.get();
}
@Override
public boolean equals(Object o)
{
if (!(o instanceof UDAggregate))
return false;
UDAggregate that = (UDAggregate) o;
return Objects.equal(name, that.name)
&& Functions.typesMatch(argTypes, that.argTypes)
&& Functions.typesMatch(returnType, that.returnType)
&& Objects.equal(stateFunction, that.stateFunction)
&& Objects.equal(finalFunction, that.finalFunction)
&& ((stateType == that.stateType) || ((stateType != null) && stateType.equals(that.stateType, true))) // ignore freezing
&& Objects.equal(initcond, that.initcond);
}
@Override
public int hashCode()
{
return Objects.hashCode(name, Functions.typeHashCode(argTypes), Functions.typeHashCode(returnType), stateFunction, finalFunction, stateType, initcond);
}
}