com.metamatrix.query.sql.symbol
Class AliasSymbol

java.lang.Object
  com.metamatrix.query.sql.symbol.Symbol
      com.metamatrix.query.sql.symbol.SelectSymbol
          com.metamatrix.query.sql.symbol.SingleElementSymbol
              com.metamatrix.query.sql.symbol.AliasSymbol

All Implemented Interfaces:

LanguageObject, Expression, java.io.Serializable, java.lang.Cloneable

public class AliasSymbol
extends SingleElementSymbol

An AliasSymbol wraps a SingleElementSymbol and changes it's name. AliasSymbols should be used to perform the aliasing of elements in a SELECT clause. They should typically NOT be used elsewhere in a query. The alias symbol takes on the type of it's underlying SingleElementSymbol. AliasSymbols are typically applied to ElementSymbol, ExpressionSymbol, and AggregateSymbol.

See Also:

Serialized Form

Field Summary

Fields inherited from class com.metamatrix.query.sql.symbol.SingleElementSymbol

SEPARATOR

Constructor Summary

AliasSymbol(java.lang.String name, SingleElementSymbol symbol)
Construct an AliasSymbol given the alias name and the underlying symbol.

Method Summary

void	acceptVisitor(LanguageVisitor visitor) Method for accepting a visitor.
java.lang.Object	clone() Return a copy of this object.
boolean	equals(java.lang.Object obj) Compare the symbol based ONLY on name.
SingleElementSymbol	getSymbol() Get the underlying symbol
java.lang.Class	getType() Get the type of the symbol
boolean	isResolved() Returns true if this symbol has been completely resolved with respect to actual runtime metadata.
void	setSymbol(SingleElementSymbol symbol) Set the underlying symbol

Methods inherited from class com.metamatrix.query.sql.symbol.SingleElementSymbol

getShortCanonicalName, getShortName, getShortName

Methods inherited from class com.metamatrix.query.sql.symbol.Symbol

getCanonical, getCanonicalName, getName, getOutputName, hashCode, setName, setOutputName, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

AliasSymbol

public AliasSymbol(java.lang.String name,
                   SingleElementSymbol symbol)

Construct an AliasSymbol given the alias name and the underlying symbol.

Parameters:

name - Name of the alias

symbol - Underlying symbol

Method Detail

getSymbol

public SingleElementSymbol getSymbol()

Get the underlying symbol

Returns:

Underlying symbol

setSymbol

public void setSymbol(SingleElementSymbol symbol)

Set the underlying symbol

Parameters:

symbol - New symbol

getType

public java.lang.Class getType()

Get the type of the symbol

Returns:

Type of the symbol

isResolved

public boolean isResolved()

Returns true if this symbol has been completely resolved with respect to actual runtime metadata. A resolved symbol has been validated that it refers to actual metadata and will have references to the real metadata IDs if necessary. Different types of symbols determine their resolution in different ways, so this method is abstract and must be implemented by subclasses.

Specified by:

isResolved in interface Expression

Specified by:

isResolved in class Symbol

Returns:

True if resolved with runtime metadata

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

clone

public java.lang.Object clone()

Return a copy of this object.

Specified by:

clone in interface LanguageObject

Specified by:

clone in class Symbol

Returns:

Deep clone of this object

equals

public boolean equals(java.lang.Object obj)

Description copied from class: Symbol

Compare the symbol based ONLY on name. Symbols are not compared based on their underlying physical metadata IDs but rather on their representation in the context of a particular query. Case is not important when comparing symbol names.

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)