org.teiid.query.sql.symbol

Class Constant

java.lang.Object

org.teiid.query.sql.symbol.Constant

All Implemented Interfaces:

Cloneable, Comparable<Constant>, LanguageObject, Expression

public class Constant
extends Object
implements Expression, Comparable<Constant>

This class represents a literal value in a SQL string. The Constant object has a value and a type for that value. In many cases, the type can be derived from the type of the value, but that is not true if the value is null. In that case, the type is unknown and is set to the null type until the type is resolved at a later point.

Nested Class Summary

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

LanguageObject.Util

Field Summary

Fields

Modifier and Type	Field and Description
static Comparator<Object>	COMPARATOR
static Constant	NULL_CONSTANT

Constructor Summary

Constructors

Constructor and Description
Constant(Object value) Construct a constant with a value, which may be null.
Constant(Object value, Class<?> type) Construct a typed constant.

Method Summary

Modifier and Type	Method and Description
void	acceptVisitor(LanguageVisitor visitor) Method for accepting a visitor.
Object	clone() Return a shallow copy of this object - value is NOT cloned!
int	compareTo(Constant o)
boolean	equals(Object obj) Compare this constant to another constant for equality.
Class<?>	getType() Get type of constant, if known
Object	getValue() Get value of constant
int	hashCode() Define hash code to be that of the underlying object to make it stable.
boolean	isBindEligible()
boolean	isMultiValued()
boolean	isNull() Return true if the constant is null.
void	setBindEligible(boolean bindEligible)
void	setMultiValued(List<?> value)
void	setType(Class<?> type) TODO: remove me when a null type is supported
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

Field Detail

NULL_CONSTANT

public static final Constant NULL_CONSTANT

COMPARATOR

public static final Comparator<Object> COMPARATOR

Constructor Detail

Constant

public Constant(Object value,
                Class<?> type)

Construct a typed constant. The specified value is not verified to be a value of the specified type. If this is not true, stuff probably won't work later on.

Parameters:

value - Constant value, may be null

type - Type for the constant, should never be null

Constant

public Constant(Object value)

Construct a constant with a value, which may be null. The data type is determined automatically from the type of the value.

Parameters:

value - Constant value, may be null

Method Detail

getType

public Class<?> getType()

Get type of constant, if known

Specified by:

getType in interface Expression

Returns:

Java class name of type

setType

public void setType(Class<?> type)

TODO: remove me when a null type is supported

Parameters:

type -

getValue

public Object getValue()

Get value of constant

Returns:

Constant value

isNull

public boolean isNull()

Return true if the constant is null.

Returns:

True if value is null

setMultiValued

public void setMultiValued(List<?> value)

isMultiValued

public boolean isMultiValued()

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

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

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

clone

public Object clone()

Return a shallow copy of this object - value is NOT cloned!

Specified by:

clone in interface LanguageObject

Overrides:

clone in class Object

Returns:

Shallow copy of object

toString

public String toString()

Return a String representation of this object using SQLStringVisitor.

Overrides:

toString in class Object

Returns:

String representation using SQLStringVisitor

compareTo

public int compareTo(Constant o)

Specified by:

compareTo in interface Comparable<Constant>

isBindEligible

public boolean isBindEligible()

setBindEligible

public void setBindEligible(boolean bindEligible)