org.teiid.query.sql.symbol
Class ExpressionSymbol

java.lang.Object
  org.teiid.query.sql.symbol.Symbol
      org.teiid.query.sql.symbol.SingleElementSymbol
          org.teiid.query.sql.symbol.ExpressionSymbol

All Implemented Interfaces:

Cloneable, LanguageObject, Expression, SelectSymbol

Direct Known Subclasses:

AggregateSymbol

public class ExpressionSymbol
extends SingleElementSymbol

This is a subclass of Symbol representing an expression in the SELECT clause. The expression may be a constant, function, or scalar subquery. The name of this symbol is always generated and typically should not be displayed. If necessary, the ExpressionSymbol may be wrapped by an AliasSymbol to register the name in a query. The definition of the symbol is the functional expression. Resolution will produce a list of groups and elements used by the expression.

Nested Class Summary

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

LanguageObject.Util

Field Summary

Fields inherited from class org.teiid.query.sql.symbol.SingleElementSymbol

SEPARATOR

Fields inherited from class org.teiid.query.sql.symbol.Symbol

outputName

Constructor Summary

	ExpressionSymbol(String name, Expression expression) Construct an ExpressionSymbol with name and expression.
protected	ExpressionSymbol(String name, String canonicalName, Expression expression) Constructor used for cloning

Method Summary

void	acceptVisitor(LanguageVisitor visitor) Method for accepting a visitor.
Object	clone() Return a deep copy of this object
boolean	equals(Object obj) ExpressionSymbol matching is not based upon the name
Expression	getExpression() Get the expression for this symbol
Class	getType() Get the type of the symbol
int	hashCode() Return a hash code for this symbol.
boolean	isResolved() If elementSymbols is not null return true, else return false
void	setExpression(Expression expression) Set the expression represented by this symbol.

Methods inherited from class org.teiid.query.sql.symbol.SingleElementSymbol

getShortName

Methods inherited from class org.teiid.query.sql.symbol.Symbol

getCanonical, getCanonicalName, getName, getOutputName, getShortCanonicalName, getShortName, setName, setOutputName, setShortCanonicalName, setShortName, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

ExpressionSymbol

protected ExpressionSymbol(String name,
                           String canonicalName,
                           Expression expression)

Constructor used for cloning

Parameters:

name -

canonicalName -

Since:

4.3

ExpressionSymbol

public ExpressionSymbol(String name,
                        Expression expression)

Construct an ExpressionSymbol with name and expression.

Method Detail

getExpression

public Expression getExpression()

Get the expression for this symbol

Returns:

Expression for this symbol

setExpression

public void setExpression(Expression expression)

Set the expression represented by this symbol.

Parameters:

expression - Expression for this expression symbol

getType

public Class getType()

Get the type of the symbol

Returns:

Type of the symbol, may be null before resolution

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.

Parameters:

visitor - Visitor being used

isResolved

public boolean isResolved()

If elementSymbols is not null return true, else return false

Specified by:

isResolved in interface Expression

Specified by:

isResolved in class Symbol

Returns:

boolean True if expression symbol has been resolved to element symbols

clone

public Object clone()

Return a deep copy of this object

Specified by:

clone in interface LanguageObject

Specified by:

clone in class Symbol

Returns:

Deep copy of this object

hashCode

public int hashCode()

Description copied from class: Symbol

Return a hash code for this symbol.

Overrides:

hashCode in class Symbol

Returns:

Hash code

See Also:

Symbol.hashCode()

equals

public boolean equals(Object obj)

ExpressionSymbol matching is not based upon the name

Overrides:

equals in class Symbol

Parameters:

obj - Other object

Returns:

True if other obj is a Symbol (or subclass) and name is equal

See Also:

Symbol.equals(java.lang.Object)