org.apache.drill.exec.expr.fn

Class DrillFuncHolder

java.lang.Object

org.apache.drill.exec.expr.fn.AbstractFuncHolder

org.apache.drill.exec.expr.fn.DrillFuncHolder

All Implemented Interfaces:

FuncHolder

Direct Known Subclasses:

DrillComplexWriterAggFuncHolder, DrillSimpleFuncHolder

public abstract class DrillFuncHolder
extends AbstractFuncHolder

Constructor Summary

Constructors

Constructor and Description
DrillFuncHolder(FunctionAttributes attributes, FunctionInitializer initializer)

Method Summary

Modifier and Type	Method and Description
protected void	addProtectedBlock(ClassGenerator<?> g, com.sun.codemodel.JBlock sub, String body, ClassGenerator.HoldingContainer[] inputVariables, com.sun.codemodel.JVar[] workspaceJVars, boolean workspaceOnly) Generate the function block itself, without surrounding comments, and whether or not the method is empty.
protected void	assignInjectableValue(ClassGenerator<?> g, com.sun.codemodel.JVar variable, WorkspaceReference ref)
protected void	checkNullHandling(FunctionTemplate.NullHandling nullHandling) Check if function type supports provided null handling strategy.
boolean	checkPrecisionRange()
protected com.sun.codemodel.JAssignmentTarget	declare(com.sun.codemodel.JBlock jBlock, ValueReference parameter, com.sun.codemodel.JType paramClass, com.sun.codemodel.JExpression paramExpression, int currentIndex) Declares specified paramExpression in specified jBlock and assigns it to the array component if required and / or returns declared expression.
protected void	declareInputVariable(com.sun.codemodel.JCodeModel model, com.sun.codemodel.JBlock jBlock, ClassGenerator.HoldingContainer inputVariable, int currentIndex) Generate the top part of a function call which simulates passing parameters into the function.
protected void	declareVarArgArray(com.sun.codemodel.JCodeModel model, com.sun.codemodel.JBlock jBlock, ClassGenerator.HoldingContainer[] inputVariables) Declares array for storing vararg function arguments.
protected com.sun.codemodel.JVar[]	declareWorkspaceVariables(ClassGenerator<?> g)
protected void	generateBody(ClassGenerator<?> g, ClassGenerator.BlockType bt, String body, ClassGenerator.HoldingContainer[] inputVariables, com.sun.codemodel.JVar[] workspaceJVars, boolean workspaceOnly) Generate the body of a Drill function by copying the source code of the corresponding function method into the generated output.
ValueReference	getAttributeParameter(int i) Returns i-th function attribute parameter.
ClassLoader	getClassLoader()
int	getCostCategory()
FunctionHolderExpression	getExpr(String name, List<LogicalExpression> args, ExpressionPosition pos) Return a reference to this function given a function alias and a list of actual arguments.
String	getInputParameters() Generates string representation of function input parameters: PARAMETER_TYPE_1-PARAMETER_MODE_1,PARAMETER_TYPE_2-PARAMETER_MODE_2 Example: VARCHAR-REQUIRED,VARCHAR-OPTIONAL Returns empty string if function has no input parameters.
FunctionTemplate.NullHandling	getNullHandling()
OutputWidthCalculator	getOutputWidthCalculator()
int	getParamCount() Number of defined input parameters.
ValueReference[]	getParameters()
TypeProtos.MajorType	getParamMajorType(int i) Drill SQL type of an input parameter.
String[]	getRegisteredNames()
TypeProtos.MajorType	getReturnType()
TypeProtos.MajorType	getReturnType(List<LogicalExpression> logicalExpressions)
ValueReference	getReturnValue()
WorkspaceReference[]	getWorkspaceVars()
boolean	isAggregating()
boolean	isConstant(int i)
boolean	isDeterministic()
boolean	isFieldReader(int i)
boolean	isInternal()
boolean	isNiladic()
boolean	isVarArg()
boolean	matches(TypeProtos.MajorType returnType, List<TypeProtos.MajorType> argTypes)
protected String	meth(String methodName)
protected String	meth(String methodName, boolean required)
com.sun.codemodel.JVar[]	renderStart(ClassGenerator<?> g, ClassGenerator.HoldingContainer[] inputVariables, FieldReference fieldReference)
String	toString()
int	variableOutputSizeEstimate()

Methods inherited from class org.apache.drill.exec.expr.fn.AbstractFuncHolder

isComplexWriterFuncHolder, isNested, renderEnd, renderMiddle

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

DrillFuncHolder

public DrillFuncHolder(FunctionAttributes attributes,
                       FunctionInitializer initializer)

Method Detail

checkNullHandling

protected void checkNullHandling(FunctionTemplate.NullHandling nullHandling)

Check if function type supports provided null handling strategy.

Keep in mind that this method is invoked in DrillFuncHolder(FunctionAttributes, FunctionInitializer) constructor so make sure not to use any state fields when overriding the method to avoid uninitialized state.

Parameters:

nullHandling - null handling strategy defined for a function

Throws:

IllegalArgumentException - if provided nullHandling is not supported

meth

protected String meth(String methodName)

meth

protected String meth(String methodName,
                      boolean required)

renderStart

public com.sun.codemodel.JVar[] renderStart(ClassGenerator<?> g,
                                            ClassGenerator.HoldingContainer[] inputVariables,
                                            FieldReference fieldReference)

Specified by:

renderStart in class AbstractFuncHolder

getExpr

public FunctionHolderExpression getExpr(String name,
                                        List<LogicalExpression> args,
                                        ExpressionPosition pos)

Description copied from interface: FuncHolder

Return a reference to this function given a function alias and a list of actual arguments.

Parameters:

name - alias used in this specific call

args - expressions of the actual function arguments

Returns:

an expression that holds the function definition (this object), actual parameters and related information

isAggregating

public boolean isAggregating()

isDeterministic

public boolean isDeterministic()

isNiladic

public boolean isNiladic()

isInternal

public boolean isInternal()

isVarArg

public boolean isVarArg()

getInputParameters

public String getInputParameters()

Generates string representation of function input parameters: PARAMETER_TYPE_1-PARAMETER_MODE_1,PARAMETER_TYPE_2-PARAMETER_MODE_2 Example: VARCHAR-REQUIRED,VARCHAR-OPTIONAL Returns empty string if function has no input parameters.

Returns:

string representation of function input parameters

getClassLoader

public ClassLoader getClassLoader()

Returns:

instance of class loader used to load function

declareWorkspaceVariables

protected com.sun.codemodel.JVar[] declareWorkspaceVariables(ClassGenerator<?> g)

assignInjectableValue

protected void assignInjectableValue(ClassGenerator<?> g,
                                     com.sun.codemodel.JVar variable,
                                     WorkspaceReference ref)

generateBody

protected void generateBody(ClassGenerator<?> g,
                            ClassGenerator.BlockType bt,
                            String body,
                            ClassGenerator.HoldingContainer[] inputVariables,
                            com.sun.codemodel.JVar[] workspaceJVars,
                            boolean workspaceOnly)

Generate the body of a Drill function by copying the source code of the corresponding function method into the generated output. For this to work, all symbol references must be absolute (they cannot refer to imports), or they must refer to local variables or class fields marked with an annotation.

To make this work, the function body is wrapped in a code block that simulates the class fields by declaring local variables of the same name, and assigning those variables based on the input and workspace variables provided.

This version is used for blocks other than the main eval block.

Parameters:

g - code generator

bt - type of the block to be added

body - source code of the block. Optional. Block will be omitted if the method body is null or empty

inputVariables - list of input variable bindings which match up to declared @Param member variables in order. The input variables have the same name as the parameters that they represent

workspaceJVars - list of workspace variables, structures the same as input variables

workspaceOnly - true if this is a setup block and we should declare only constant workspace variables, false to declare all variables

addProtectedBlock

protected void addProtectedBlock(ClassGenerator<?> g,
                                 com.sun.codemodel.JBlock sub,
                                 String body,
                                 ClassGenerator.HoldingContainer[] inputVariables,
                                 com.sun.codemodel.JVar[] workspaceJVars,
                                 boolean workspaceOnly)

Generate the function block itself, without surrounding comments, and whether or not the method is empty.

declareVarArgArray

protected void declareVarArgArray(com.sun.codemodel.JCodeModel model,
                                  com.sun.codemodel.JBlock jBlock,
                                  ClassGenerator.HoldingContainer[] inputVariables)

Declares array for storing vararg function arguments.

Parameters:

model - code model to generate the code

jBlock - block of code to be populated

inputVariables - array of input variables for current function

declareInputVariable

protected void declareInputVariable(com.sun.codemodel.JCodeModel model,
                                    com.sun.codemodel.JBlock jBlock,
                                    ClassGenerator.HoldingContainer inputVariable,
                                    int currentIndex)

Generate the top part of a function call which simulates passing parameters into the function. Given the following declaration:

 public static class UnionIsBigInt implements DrillSimpleFunc {

Parameters:

model - code model to generate the code

jBlock - block of code to be populated

inputVariable - input variable for current function

currentIndex - index of current parameter

declare

protected com.sun.codemodel.JAssignmentTarget declare(com.sun.codemodel.JBlock jBlock,
                                                      ValueReference parameter,
                                                      com.sun.codemodel.JType paramClass,
                                                      com.sun.codemodel.JExpression paramExpression,
                                                      int currentIndex)

Declares specified paramExpression in specified jBlock and assigns it to the array component if required and / or returns declared expression.

Parameters:

jBlock - target block where declaration is added

parameter - function parameter which should be declared

paramClass - type of the declared variable

paramExpression - expression to be declared

currentIndex - index of current parameter

Returns:

declared expression

matches

public boolean matches(TypeProtos.MajorType returnType,
                       List<TypeProtos.MajorType> argTypes)

getParamMajorType

public TypeProtos.MajorType getParamMajorType(int i)

Description copied from interface: FuncHolder

Drill SQL type of an input parameter.

getParamCount

public int getParamCount()

Description copied from interface: FuncHolder

Number of defined input parameters.

isConstant

public boolean isConstant(int i)

getAttributeParameter

public ValueReference getAttributeParameter(int i)

Returns i-th function attribute parameter. For the case when current function is vararg and specified index is greater than or equals to the attributes count, the last function attribute parameter is returned.

Parameters:

i - index of function attribute parameter to be returned

Returns:

i-th function attribute parameter

isFieldReader

public boolean isFieldReader(int i)

getReturnType

public TypeProtos.MajorType getReturnType(List<LogicalExpression> logicalExpressions)

getOutputWidthCalculator

public OutputWidthCalculator getOutputWidthCalculator()

variableOutputSizeEstimate

public int variableOutputSizeEstimate()

getNullHandling

public FunctionTemplate.NullHandling getNullHandling()

getRegisteredNames

public String[] getRegisteredNames()

getCostCategory

public int getCostCategory()

getParameters

public ValueReference[] getParameters()

checkPrecisionRange

public boolean checkPrecisionRange()

getReturnType

public TypeProtos.MajorType getReturnType()

getReturnValue

public ValueReference getReturnValue()

getWorkspaceVars

public WorkspaceReference[] getWorkspaceVars()

toString

public String toString()

Overrides:

toString in class Object