Package org.apache.drill.common.expression

Class FunctionHolderExpression

java.lang.Object

org.apache.drill.common.expression.LogicalExpressionBase

org.apache.drill.common.expression.FunctionHolderExpression

All Implemented Interfaces:

Iterable<LogicalExpression>, LogicalExpression

Direct Known Subclasses:

DrillFuncHolderExpr, HiveFuncHolderExpr

public abstract class FunctionHolderExpression
extends LogicalExpressionBase

Represents an actual call (a reference) to a declared function. Holds the name used (functions can have multiple aliases), the function declaration, and the actual argument expressions used in this call. This might be better named FunctionCallExpression as it represents a use of a function. Subclasses hold references to the declaration depending on the type (Drill, Hive) of the function.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.drill.common.expression.LogicalExpression

LogicalExpression.De, LogicalExpression.Se

Field Summary

Fields

Modifier and Type	Field	Description
final com.google.common.collect.ImmutableList<LogicalExpression>	args
final String	nameUsed

Constructor Summary

Constructors

Constructor	Description
FunctionHolderExpression(String nameUsed, ExpressionPosition pos, List<LogicalExpression> args)

Method Summary

Modifier and Type	Method	Description
<T, V, E extends Exception> T	accept(ExprVisitor<T,V,E> visitor, V value)
abstract boolean	argConstantOnly(int i)	constant input expected for i'th argument?
abstract FunctionHolderExpression	copy(List<LogicalExpression> args)
FieldReference	getFieldReference()
abstract FuncHolder	getHolder()	Return the underlying function implementation holder.
String	getName()	A function can have multiple names, it returns the function name used in the query.
abstract boolean	isAggregating()
abstract boolean	isRandom()	Is the function output non-deterministic?
void	setFieldReference(FieldReference fieldReference)	Set the FieldReference to be used during generating code.
String	toString()

Methods inherited from class org.apache.drill.common.expression.LogicalExpressionBase

getCumulativeCost, getDescription, getMajorType, getPosition, getSelfCost, i

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, iterator, spliterator

Field Details

args

public final com.google.common.collect.ImmutableList<LogicalExpression> args

nameUsed

public final String nameUsed

Constructor Details

FunctionHolderExpression

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

Method Details

accept

public <T,
V,
E extends Exception> T accept(ExprVisitor<T,V,E> visitor,
 V value)
                                     throws E

Throws:

E

getName

public String getName()

A function can have multiple names, it returns the function name used in the query.

Returns:

The function name used in the query.

argConstantOnly

public abstract boolean argConstantOnly(int i)

constant input expected for i'th argument?

Parameters:

i -

Returns:

True if a constant input is expected for the i'th argument. False otherwise.

isAggregating

public abstract boolean isAggregating()

Returns:

aggregating function or not

isRandom

public abstract boolean isRandom()

Is the function output non-deterministic?

copy

public abstract FunctionHolderExpression copy(List<LogicalExpression> args)

Returns:

a copy of FunctionHolderExpression, with passed in argument list.

getHolder

public abstract FuncHolder getHolder()

Return the underlying function implementation holder. That is, returns the function declaration.

getFieldReference

public FieldReference getFieldReference()

setFieldReference

public void setFieldReference(FieldReference fieldReference)

Set the FieldReference to be used during generating code.

Parameters:

fieldReference - FieldReference to set.

toString

public String toString()

Overrides:

toString in class Object