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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.ArrayList;
import java.util.Collection;
import java.util.List;
import org.apache.cassandra.schema.SchemaConstants;
import org.apache.cassandra.db.marshal.*;
import org.apache.cassandra.exceptions.OperationExecutionException;
import org.apache.cassandra.transport.ProtocolVersion;
/**
* Operation functions (Mathematics).
*
*/
public final class OperationFcts
{
private static enum OPERATION
{
ADDITION('+', "_add")
{
protected ByteBuffer executeOnNumerics(NumberType resultType,
NumberType leftType,
ByteBuffer left,
NumberType rightType,
ByteBuffer right)
{
return resultType.add(leftType, left, rightType, right);
}
@Override
protected ByteBuffer executeOnTemporals(TemporalType type,
ByteBuffer temporal,
ByteBuffer duration)
{
return type.addDuration(temporal, duration);
}
},
SUBSTRACTION('-', "_substract")
{
protected ByteBuffer executeOnNumerics(NumberType resultType,
NumberType leftType,
ByteBuffer left,
NumberType rightType,
ByteBuffer right)
{
return resultType.substract(leftType, left, rightType, right);
}
@Override
protected ByteBuffer executeOnTemporals(TemporalType type,
ByteBuffer temporal,
ByteBuffer duration)
{
return type.substractDuration(temporal, duration);
}
},
MULTIPLICATION('*', "_multiply")
{
protected ByteBuffer executeOnNumerics(NumberType resultType,
NumberType leftType,
ByteBuffer left,
NumberType rightType,
ByteBuffer right)
{
return resultType.multiply(leftType, left, rightType, right);
}
},
DIVISION('/', "_divide")
{
protected ByteBuffer executeOnNumerics(NumberType resultType,
NumberType leftType,
ByteBuffer left,
NumberType rightType,
ByteBuffer right)
{
return resultType.divide(leftType, left, rightType, right);
}
},
MODULO('%', "_modulo")
{
protected ByteBuffer executeOnNumerics(NumberType resultType,
NumberType leftType,
ByteBuffer left,
NumberType rightType,
ByteBuffer right)
{
return resultType.mod(leftType, left, rightType, right);
}
};
/**
* The operator symbol.
*/
private final char symbol;
/**
* The name of the function associated to this operation
*/
private final String functionName;
private OPERATION(char symbol, String functionName)
{
this.symbol = symbol;
this.functionName = functionName;
}
/**
* Executes the operation between the specified numeric operand.
*
* @param resultType the result ype of the operation
* @param leftType the type of the left operand
* @param left the left operand
* @param rightType the type of the right operand
* @param right the right operand
* @return the operation result
*/
protected abstract ByteBuffer executeOnNumerics(NumberType resultType,
NumberType leftType,
ByteBuffer left,
NumberType rightType,
ByteBuffer right);
/**
* Executes the operation on the specified temporal operand.
*
* @param type the temporal type
* @param temporal the temporal value
* @param duration the duration
* @return the operation result
*/
protected ByteBuffer executeOnTemporals(TemporalType type,
ByteBuffer temporal,
ByteBuffer duration)
{
throw new UnsupportedOperationException();
}
/**
* Returns the {@code OPERATOR} associated to the specified function.
* @param functionName the function name
* @return the {@code OPERATOR} associated to the specified function
*/
public static OPERATION fromFunctionName(String functionName)
{
for (OPERATION operator : values())
{
if (operator.functionName.equals(functionName))
return operator;
}
return null;
}
/**
* Returns the {@code OPERATOR} with the specified symbol.
* @param functionName the function name
* @return the {@code OPERATOR} with the specified symbol
*/
public static OPERATION fromSymbol(char symbol)
{
for (OPERATION operator : values())
{
if (operator.symbol == symbol)
return operator;
}
return null;
}
}
/**
* The name of the function used to perform negations
*/
public static final String NEGATION_FUNCTION_NAME = "_negate";
public static Collection all()
{
List functions = new ArrayList<>();
final NumberType[] numericTypes = new NumberType[] { ByteType.instance,
ShortType.instance,
Int32Type.instance,
LongType.instance,
FloatType.instance,
DoubleType.instance,
DecimalType.instance,
IntegerType.instance,
CounterColumnType.instance};
for (NumberType left : numericTypes)
{
for (NumberType right : numericTypes)
{
NumberType returnType = returnType(left, right);
for (OPERATION operation : OPERATION.values())
functions.add(new NumericOperationFunction(returnType, left, operation, right));
}
functions.add(new NumericNegationFunction(left));
}
for (OPERATION operation : new OPERATION[] {OPERATION.ADDITION, OPERATION.SUBSTRACTION})
{
functions.add(new TemporalOperationFunction(TimestampType.instance, operation));
functions.add(new TemporalOperationFunction(SimpleDateType.instance, operation));
}
return functions;
}
/**
* Checks if the function with the specified name is an operation.
*
* @param function the function name
* @return {@code true} if the function is an operation, {@code false} otherwise.
*/
public static boolean isOperation(FunctionName function)
{
return SchemaConstants.SYSTEM_KEYSPACE_NAME.equals(function.keyspace)
&& OPERATION.fromFunctionName(function.name) != null;
}
/**
* Checks if the function with the specified name is a negation.
*
* @param function the function name
* @return {@code true} if the function is an negation, {@code false} otherwise.
*/
public static boolean isNegation(FunctionName function)
{
return SchemaConstants.SYSTEM_KEYSPACE_NAME.equals(function.keyspace)&& NEGATION_FUNCTION_NAME.equals(function.name);
}
/**
* Returns the operator associated to the specified function.
*
* @return the operator associated to the specified function.
*/
public static char getOperator(FunctionName function)
{
assert SchemaConstants.SYSTEM_KEYSPACE_NAME.equals(function.keyspace);
return OPERATION.fromFunctionName(function.name).symbol;
}
/**
* Returns the name of the function associated to the specified operator.
*
* @param operator the operator
* @return the name of the function associated to the specified operator
*/
public static FunctionName getFunctionNameFromOperator(char operator)
{
return FunctionName.nativeFunction(OPERATION.fromSymbol(operator).functionName);
}
/**
* Determine the return type for an operation between the specified types.
*
* @param left the type of the left operand
* @param right the type of the right operand
* @return the return type for an operation between the specified types
*/
private static NumberType returnType(NumberType left, NumberType right)
{
boolean isFloatingPoint = left.isFloatingPoint() || right.isFloatingPoint();
int size = Math.max(size(left), size(right));
return isFloatingPoint
? floatPointType(size)
: integerType(size);
}
/**
* Returns the number of bytes used to represent a value of this type.
* @return the number of bytes used to represent a value of this type or {@code Integer.MAX} if the number of bytes
* is not limited.
*/
private static int size(NumberType type)
{
int size = type.valueLengthIfFixed();
if (size > 0)
return size;
// tinyint and smallint type are not fixed length types even if they should be.
// So we need to handle them in a special way.
if (type == ByteType.instance)
return 1;
if (type == ShortType.instance)
return 2;
if (type.isCounter())
return LongType.instance.valueLengthIfFixed();
return Integer.MAX_VALUE;
}
private static NumberType floatPointType(int size)
{
switch (size)
{
case 4: return FloatType.instance;
case 8: return DoubleType.instance;
default: return DecimalType.instance;
}
}
private static NumberType integerType(int size)
{
switch (size)
{
case 1: return ByteType.instance;
case 2: return ShortType.instance;
case 4: return Int32Type.instance;
case 8: return LongType.instance;
default: return IntegerType.instance;
}
}
/**
* The class must not be instantiated.
*/
private OperationFcts()
{
}
/**
* Base class for functions that execute operations.
*/
private static abstract class OperationFunction extends NativeScalarFunction
{
private final OPERATION operation;
public OperationFunction(AbstractType returnType,
AbstractType left,
OPERATION operation,
AbstractType right)
{
super(operation.functionName, returnType, left, right);
this.operation = operation;
}
@Override
public final String columnName(List columnNames)
{
return String.format("%s %s %s", columnNames.get(0), getOperator(), columnNames.get(1));
}
public final ByteBuffer execute(ProtocolVersion protocolVersion, List parameters)
{
ByteBuffer left = parameters.get(0);
ByteBuffer right = parameters.get(1);
if (left == null || !left.hasRemaining() || right == null || !right.hasRemaining())
return null;
try
{
return doExecute(left, operation, right);
}
catch (Exception e)
{
throw OperationExecutionException.create(getOperator(), argTypes, e);
}
}
protected abstract ByteBuffer doExecute(ByteBuffer left, OPERATION operation, ByteBuffer right);
/**
* Returns the operator symbol.
* @return the operator symbol
*/
private final char getOperator()
{
return operation.symbol;
}
}
/**
* Function that execute operations on numbers.
*/
private static class NumericOperationFunction extends OperationFunction
{
public NumericOperationFunction(NumberType returnType,
NumberType left,
OPERATION operation,
NumberType right)
{
super(returnType, left, operation, right);
}
@Override
protected ByteBuffer doExecute(ByteBuffer left, OPERATION operation, ByteBuffer right)
{
NumberType leftType = (NumberType) argTypes().get(0);
NumberType rightType = (NumberType) argTypes().get(1);
NumberType resultType = (NumberType) returnType();
return operation.executeOnNumerics(resultType, leftType, left, rightType, right);
}
}
/**
* Function that execute operations on temporals (timestamp, date, ...).
*/
private static class TemporalOperationFunction extends OperationFunction
{
public TemporalOperationFunction(TemporalType type,
OPERATION operation)
{
super(type, type, operation, DurationType.instance);
}
@Override
protected ByteBuffer doExecute(ByteBuffer left, OPERATION operation, ByteBuffer right)
{
TemporalType resultType = (TemporalType) returnType();
return operation.executeOnTemporals(resultType, left, right);
}
}
/**
* Function that negate a number.
*/
private static class NumericNegationFunction extends NativeScalarFunction
{
public NumericNegationFunction(NumberType inputType)
{
super(NEGATION_FUNCTION_NAME, inputType, inputType);
}
@Override
public final String columnName(List columnNames)
{
return String.format("-%s", columnNames.get(0));
}
public final ByteBuffer execute(ProtocolVersion protocolVersion, List parameters)
{
ByteBuffer input = parameters.get(0);
if (input == null)
return null;
NumberType inputType = (NumberType) argTypes().get(0);
return inputType.negate(input);
}
}
}
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