org.apache.cassandra.cql3.functions

Class UDFunction

java.lang.Object

org.apache.cassandra.cql3.functions.AbstractFunction

org.apache.cassandra.cql3.functions.UDFunction

All Implemented Interfaces:

AssignmentTestable, Function, ScalarFunction, SchemaElement

Direct Known Subclasses:

JavaBasedUDFunction

public abstract class UDFunction
extends AbstractFunction
implements ScalarFunction, SchemaElement

Base class for User Defined Functions.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.cassandra.cql3.AssignmentTestable

AssignmentTestable.TestResult

Nested classes/interfaces inherited from interface org.apache.cassandra.cql3.SchemaElement

SchemaElement.SchemaElementType

Field Summary

Fields

Modifier and Type	Field and Description
protected TypeCodec<java.lang.Object>[]	argCodecs
protected java.util.List<ColumnIdentifier>	argNames
protected java.lang.String	body
protected boolean	calledOnNullInput
protected java.lang.String	language
protected static org.slf4j.Logger	logger
protected TypeCodec<java.lang.Object>	returnCodec
protected UDFContext	udfContext

Fields inherited from class org.apache.cassandra.cql3.functions.AbstractFunction

argTypes, name, returnType

Fields inherited from interface org.apache.cassandra.cql3.functions.Function

UNRESOLVED

Fields inherited from interface org.apache.cassandra.cql3.SchemaElement

NAME_COMPARATOR

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	UDFunction(FunctionName name, java.util.List<ColumnIdentifier> argNames, java.util.List<AbstractType<?>> argTypes, AbstractType<?> returnType, boolean calledOnNullInput, java.lang.String language, java.lang.String body)
protected	UDFunction(FunctionName name, java.util.List<ColumnIdentifier> argNames, java.util.List<AbstractType<?>> argTypes, DataType[] argDataTypes, AbstractType<?> returnType, DataType returnDataType, boolean calledOnNullInput, java.lang.String language, java.lang.String body)

Method Summary

Modifier and Type	Method and Description
java.util.List<ColumnIdentifier>	argNames()
static void	assertUdfsEnabled(java.lang.String language)
java.lang.String	body()
java.util.Optional<Difference>	compare(Function function)
protected java.lang.Object	compose(ProtocolVersion protocolVersion, int argIndex, java.nio.ByteBuffer value) Used by UDF implementations (both Java code generated by JavaBasedUDFunction and script executor ScriptBasedUDFunction) to convert the C* serialized representation to the Java object representation.
protected static java.lang.Object	compose(TypeCodec<java.lang.Object>[] codecs, ProtocolVersion protocolVersion, int argIndex, java.nio.ByteBuffer value)
static UDFunction	create(FunctionName name, java.util.List<ColumnIdentifier> argNames, java.util.List<AbstractType<?>> argTypes, AbstractType<?> returnType, boolean calledOnNullInput, java.lang.String language, java.lang.String body)
static UDFunction	createBrokenFunction(FunctionName name, java.util.List<ColumnIdentifier> argNames, java.util.List<AbstractType<?>> argTypes, AbstractType<?> returnType, boolean calledOnNullInput, java.lang.String language, java.lang.String body, InvalidRequestException reason) It can happen that a function has been declared (is listed in the scheam) but cannot be loaded (maybe only on some nodes).
protected java.nio.ByteBuffer	decompose(ProtocolVersion protocolVersion, java.lang.Object value) Used by UDF implementations (both Java code generated by JavaBasedUDFunction and script executor ScriptBasedUDFunction) to convert the Java object representation for the return value to the C* serialized representation.
protected static java.nio.ByteBuffer	decompose(TypeCodec<java.lang.Object> codec, ProtocolVersion protocolVersion, java.lang.Object value)
SchemaElement.SchemaElementType	elementType() Return the schema element type
boolean	equals(java.lang.Object o)
java.nio.ByteBuffer	execute(ProtocolVersion protocolVersion, java.util.List<java.nio.ByteBuffer> parameters) Applies this function to the specified parameter.
protected abstract java.lang.Object	executeAggregateUserDefined(ProtocolVersion protocolVersion, java.lang.Object firstParam, java.util.List<java.nio.ByteBuffer> parameters)
java.lang.Object	executeForAggregate(ProtocolVersion protocolVersion, java.lang.Object firstParam, java.util.List<java.nio.ByteBuffer> parameters) Like ScalarFunction.execute(ProtocolVersion, List) but the first parameter is already in non-serialized form.
protected abstract java.nio.ByteBuffer	executeUserDefined(ProtocolVersion protocolVersion, java.util.List<java.nio.ByteBuffer> parameters)
protected abstract java.util.concurrent.ExecutorService	executor()
int	hashCode()
boolean	isAggregate() Checks whether the function is an aggregate function or not.
boolean	isCallableWrtNullable(java.util.List<java.nio.ByteBuffer> parameters)
boolean	isCalledOnNullInput()
boolean	isNative() Checks whether the function is a native/hard coded one or not.
boolean	isPure() Checks whether the function is a pure function (as in doesn't depend on, nor produces side effects) or not.
java.lang.String	language()
boolean	referencesUserType(java.nio.ByteBuffer name)
java.lang.String	toCqlString(boolean withInternals, boolean ifNotExists) Returns a CQL representation of this element
static UDFunction	tryCreate(FunctionName name, java.util.List<ColumnIdentifier> argNames, java.util.List<AbstractType<?>> argTypes, AbstractType<?> returnType, boolean calledOnNullInput, java.lang.String language, java.lang.String body)
UDFunction	withUpdatedUserType(UserType udt)

Methods inherited from class org.apache.cassandra.cql3.functions.AbstractFunction

addFunctionsTo, argTypes, argumentsList, columnName, elementKeyspace, elementName, name, returnType, testAssignment, toCqlString, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.cassandra.cql3.functions.ScalarFunction

isMonotonic, partialApplication

Methods inherited from interface org.apache.cassandra.cql3.functions.Function

addFunctionsTo, argTypes, columnName, name, returnType

Methods inherited from interface org.apache.cassandra.cql3.AssignmentTestable

testAssignment

Methods inherited from interface org.apache.cassandra.cql3.SchemaElement

elementKeyspace, elementKeyspaceQuotedIfNeeded, elementName, elementNameQuotedIfNeeded

Field Detail

logger

protected static final org.slf4j.Logger logger

argNames

protected final java.util.List<ColumnIdentifier> argNames

language

protected final java.lang.String language

body

protected final java.lang.String body

argCodecs

protected final TypeCodec<java.lang.Object>[] argCodecs

returnCodec

protected final TypeCodec<java.lang.Object> returnCodec

calledOnNullInput

protected final boolean calledOnNullInput

udfContext

protected final UDFContext udfContext

Constructor Detail

UDFunction

protected UDFunction(FunctionName name,
                     java.util.List<ColumnIdentifier> argNames,
                     java.util.List<AbstractType<?>> argTypes,
                     AbstractType<?> returnType,
                     boolean calledOnNullInput,
                     java.lang.String language,
                     java.lang.String body)

UDFunction

protected UDFunction(FunctionName name,
                     java.util.List<ColumnIdentifier> argNames,
                     java.util.List<AbstractType<?>> argTypes,
                     DataType[] argDataTypes,
                     AbstractType<?> returnType,
                     DataType returnDataType,
                     boolean calledOnNullInput,
                     java.lang.String language,
                     java.lang.String body)

Method Detail

tryCreate

public static UDFunction tryCreate(FunctionName name,
                                   java.util.List<ColumnIdentifier> argNames,
                                   java.util.List<AbstractType<?>> argTypes,
                                   AbstractType<?> returnType,
                                   boolean calledOnNullInput,
                                   java.lang.String language,
                                   java.lang.String body)

create

public static UDFunction create(FunctionName name,
                                java.util.List<ColumnIdentifier> argNames,
                                java.util.List<AbstractType<?>> argTypes,
                                AbstractType<?> returnType,
                                boolean calledOnNullInput,
                                java.lang.String language,
                                java.lang.String body)

createBrokenFunction

public static UDFunction createBrokenFunction(FunctionName name,
                                              java.util.List<ColumnIdentifier> argNames,
                                              java.util.List<AbstractType<?>> argTypes,
                                              AbstractType<?> returnType,
                                              boolean calledOnNullInput,
                                              java.lang.String language,
                                              java.lang.String body,
                                              InvalidRequestException reason)

It can happen that a function has been declared (is listed in the scheam) but cannot be loaded (maybe only on some nodes). This is the case for instance if the class defining the class is not on the classpath for some of the node, or after a restart. In that case, we create a "fake" function so that: 1) the broken function can be dropped easily if that is what people want to do. 2) we return a meaningful error message if the function is executed (something more precise than saying that the function doesn't exist)

elementType

public SchemaElement.SchemaElementType elementType()

Description copied from interface: SchemaElement

Return the schema element type

Specified by:

elementType in interface SchemaElement

Returns:

the schema element type

toCqlString

public java.lang.String toCqlString(boolean withInternals,
                                    boolean ifNotExists)

Description copied from interface: SchemaElement

Returns a CQL representation of this element

Specified by:

toCqlString in interface SchemaElement

Parameters:

withInternals - if the internals part of the CQL should be exposed.

ifNotExists - if "IF NOT EXISTS" should be included.

Returns:

a CQL representation of this element

isPure

public boolean isPure()

Description copied from interface: Function

Checks whether the function is a pure function (as in doesn't depend on, nor produces side effects) or not.

Specified by:

isPure in interface Function

Returns:

true if the function is a pure function, false otherwise.

execute

public final java.nio.ByteBuffer execute(ProtocolVersion protocolVersion,
                                         java.util.List<java.nio.ByteBuffer> parameters)

Description copied from interface: ScalarFunction

Applies this function to the specified parameter.

Specified by:

execute in interface ScalarFunction

Parameters:

protocolVersion - protocol version used for parameters and return value

parameters - the input parameters

Returns:

the result of applying this function to the parameter

executeForAggregate

public final java.lang.Object executeForAggregate(ProtocolVersion protocolVersion,
                                                  java.lang.Object firstParam,
                                                  java.util.List<java.nio.ByteBuffer> parameters)

Like ScalarFunction.execute(ProtocolVersion, List) but the first parameter is already in non-serialized form. Remaining parameters (2nd paramters and all others) are in parameters. This is used to prevent superfluous (de)serialization of the state of aggregates. Means: scalar functions of aggregates are called using this variant.

assertUdfsEnabled

public static void assertUdfsEnabled(java.lang.String language)

executor

protected abstract java.util.concurrent.ExecutorService executor()

isCallableWrtNullable

public boolean isCallableWrtNullable(java.util.List<java.nio.ByteBuffer> parameters)

executeUserDefined

protected abstract java.nio.ByteBuffer executeUserDefined(ProtocolVersion protocolVersion,
                                                          java.util.List<java.nio.ByteBuffer> parameters)

executeAggregateUserDefined

protected abstract java.lang.Object executeAggregateUserDefined(ProtocolVersion protocolVersion,
                                                                java.lang.Object firstParam,
                                                                java.util.List<java.nio.ByteBuffer> parameters)

isAggregate

public boolean isAggregate()

Description copied from interface: Function

Checks whether the function is an aggregate function or not.

Specified by:

isAggregate in interface Function

Returns:

true if the function is an aggregate function, false otherwise.

isNative

public boolean isNative()

Description copied from interface: Function

Checks whether the function is a native/hard coded one or not.

Specified by:

isNative in interface Function

Returns:

true if the function is a native/hard coded one, false otherwise.

isCalledOnNullInput

public boolean isCalledOnNullInput()

Specified by:

isCalledOnNullInput in interface ScalarFunction

argNames

public java.util.List<ColumnIdentifier> argNames()

body

public java.lang.String body()

language

public java.lang.String language()

compose

protected java.lang.Object compose(ProtocolVersion protocolVersion,
                                   int argIndex,
                                   java.nio.ByteBuffer value)

Used by UDF implementations (both Java code generated by JavaBasedUDFunction and script executor ScriptBasedUDFunction) to convert the C* serialized representation to the Java object representation.

Parameters:

protocolVersion - the native protocol version used for serialization

argIndex - index of the UDF input argument

compose

protected static java.lang.Object compose(TypeCodec<java.lang.Object>[] codecs,
                                          ProtocolVersion protocolVersion,
                                          int argIndex,
                                          java.nio.ByteBuffer value)

decompose

protected java.nio.ByteBuffer decompose(ProtocolVersion protocolVersion,
                                        java.lang.Object value)

Used by UDF implementations (both Java code generated by JavaBasedUDFunction and script executor ScriptBasedUDFunction) to convert the Java object representation for the return value to the C* serialized representation.

Parameters:

protocolVersion - the native protocol version used for serialization

decompose

protected static java.nio.ByteBuffer decompose(TypeCodec<java.lang.Object> codec,
                                               ProtocolVersion protocolVersion,
                                               java.lang.Object value)

referencesUserType

public boolean referencesUserType(java.nio.ByteBuffer name)

Specified by:

referencesUserType in interface Function

Overrides:

referencesUserType in class AbstractFunction

withUpdatedUserType

public UDFunction withUpdatedUserType(UserType udt)

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class AbstractFunction

compare

public java.util.Optional<Difference> compare(Function function)

Specified by:

compare in interface Function

hashCode

public int hashCode()

Overrides:

hashCode in class AbstractFunction