java.lang.Object
- org.teiid.query.sql.symbol.Reference

All Implemented Interfaces:

Cloneable, LanguageObject, ContextReference, Expression
```
public class Reference
extends Object
implements Expression, ContextReference
```
This class represents a reference (positional from the user query, or to an element from another scope). This reference may resolve to many different values during evaluation. For any particular bound value, it is treated as a constant.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static interface Reference.Constraint
- Nested classes/interfaces inherited from interface org.teiid.query.sql.LanguageObject
  LanguageObject.Util

Constructor Summary

Constructors
Constructor Description

Reference(int refIndex)
Constructor for a positional Reference.

Reference(ElementSymbol expression)
Constructor for an element Reference.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`acceptVisitor(LanguageVisitor visitor)`	Method for accepting a visitor.
`Object`	`clone()`	Implement clone to make objects cloneable.
`boolean`	`equals(Object obj)`	Compare this constant to another constant for equality.
`Reference.Constraint`	`getConstraint()`
`String`	`getContextSymbol()`
`ElementSymbol`	`getExpression()`
`int`	`getIndex()`
`Class<?>`	`getType()`	Get the return type of this expression.
`int`	`hashCode()`	Define hash code to be that of the underlying object to make it stable.
`boolean`	`isCorrelated()`
`boolean`	`isOptional()`
`boolean`	`isPositional()`
`void`	`setConstraint(Reference.Constraint constraint)`
`void`	`setExpression(ElementSymbol expression)`
`void`	`setOptional(boolean optional)`
`void`	`setType(Class<?> type)`
`String`	`toString()`	Return a String representation of this object using SQLStringVisitor.

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Reference
```
public Reference(int refIndex)
```
    Constructor for a positional Reference.
  - Reference
```
public Reference(ElementSymbol expression)
```
    Constructor for an element Reference.
- Method Detail
  - getConstraint
```
public Reference.Constraint getConstraint()
```
  - setConstraint
```
public void setConstraint(Reference.Constraint constraint)
```
  - getIndex
```
public int getIndex()
```
  - getContextSymbol
```
public String getContextSymbol()
```
    Specified by:
    
    getContextSymbol in interface ContextReference
  - getExpression
```
public ElementSymbol getExpression()
```
  - getType
```
public Class<?> getType()
```
    Description copied from interface: Expression
    
    Get the return type of this expression.
    
    Specified by:
    
    getType in interface Expression
    
    Returns:
    
    Java class may be null prior to being resolved
  - acceptVisitor
```
public void acceptVisitor(LanguageVisitor visitor)
```
    Description copied from interface: LanguageObject
    
    Method for accepting a visitor. It is the responsibility of the language object to call back on the visitor.
    
    Specified by:
    
    acceptVisitor in interface LanguageObject
    
    Parameters:
    
    visitor - Visitor being used
  - clone
```
public Object clone()
```
    Description copied from interface: LanguageObject
    
    Implement clone to make objects cloneable.
    
    Specified by:
    
    clone in interface LanguageObject
    
    Overrides:
    
    clone in class Object
    
    Returns:
    
    Deep clone of this object
    
    See Also:
    
    Object.clone()
  - equals
```
public boolean equals(Object obj)
```
    Compare this constant to another constant for equality.
    
    Overrides:
    
    equals in class Object
    
    Parameters:
    
    obj - Other object
    
    Returns:
    
    True if constants are equal
  - setType
```
public void setType(Class<?> type)
```
  - hashCode
```
public int hashCode()
```
    Define hash code to be that of the underlying object to make it stable.
    
    Overrides:
    
    hashCode in class Object
    
    Returns:
    
    Hash code, based on value
  - toString
```
public String toString()
```
    Return a String representation of this object using SQLStringVisitor.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    String representation using SQLStringVisitor
  - isCorrelated
```
public boolean isCorrelated()
```
  - isPositional
```
public boolean isPositional()
```
  - setExpression
```
public void setExpression(ElementSymbol expression)
```
  - isOptional
```
public boolean isOptional()
```
  - setOptional
```
public void setOptional(boolean optional)
```

Constructor	Description
`Reference(int refIndex)`	Constructor for a positional Reference.
`Reference(ElementSymbol expression)`	Constructor for an element Reference.

Class Reference

Nested Class Summary

Nested classes/interfaces inherited from interface org.teiid.query.sql.LanguageObject

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Reference

Reference

Method Detail

getConstraint

setConstraint

getIndex

getContextSymbol

getExpression

getType

acceptVisitor

clone

equals

setType

hashCode

toString

isCorrelated

isPositional

setExpression

isOptional

setOptional