org.teiid.query.sql.lang

Class Select

java.lang.Object

org.teiid.query.sql.lang.Select

All Implemented Interfaces:

Cloneable, LanguageObject

public class Select
extends Object
implements LanguageObject

This class represents the SELECT clause of a query, which defines what elements or expressions are returned from the query.

Nested Class Summary

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

LanguageObject.Util

Constructor Summary

Constructors

Constructor and Description
Select() Constructs a default instance of this class.
Select(List<? extends Expression> symbols) Constructs an instance of this class from an ordered set of symbols.

Method Summary

Modifier and Type	Method and Description
void	acceptVisitor(LanguageVisitor visitor) Method for accepting a visitor.
void	addSymbol(Expression symbol)
void	addSymbols(Collection<? extends Expression> toAdd)
void	clearSymbols() Remove all current symbols
Select	clone() Return a deep copy of this Select.
boolean	containsSymbol(Expression symbol) Checks if a symbol is in the Select.
boolean	equals(Object obj) Compare two Selects for equality.
int	getCount() Returns the number of symbols in select.
List<Expression>	getProjectedSymbols() Get the ordered list of all elements returned by this select.
Expression	getSymbol(int index) Returns the select symbol at the specified index.
List<Expression>	getSymbols() Returns an ordered list of the symbols in the select.
int	hashCode() Get hashcode for Select.
boolean	isDistinct() Checks whether the select is distinct
boolean	isStar() Checks for a Select * clause
void	setDistinct(boolean isDistinct) Set whether select is distinct.
void	setSymbols(Collection<? extends Expression> symbols) Sets an ordered list of the symbols in the select.
String	toString() Returns a string representation of an instance of this class.

Methods inherited from class java.lang.Object

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

Constructor Detail

Select

public Select()

Constructs a default instance of this class.

Select

public Select(List<? extends Expression> symbols)

Constructs an instance of this class from an ordered set of symbols.

Parameters:

symbols - The ordered list of symbols

Method Detail

getCount

public int getCount()

Returns the number of symbols in select.

Returns:

Get count of number of symbols in select

isStar

public boolean isStar()

Checks for a Select * clause

Returns:

True if Select * is used

getSymbols

public List<Expression> getSymbols()

Returns an ordered list of the symbols in the select.

Parameters:

Get - list of SelectSymbol in SELECT

setSymbols

public void setSymbols(Collection<? extends Expression> symbols)

Sets an ordered list of the symbols in the select. Reuses the current symbol list.

Parameters:

symbols - list of SelectSymbol in SELECT

getSymbol

public Expression getSymbol(int index)

Returns the select symbol at the specified index.

Parameters:

index - Index to get

Returns:

The variable identifier at the index

addSymbol

public void addSymbol(Expression symbol)

Parameters:

symbol - New symbol

addSymbols

public void addSymbols(Collection<? extends Expression> toAdd)

clearSymbols

public void clearSymbols()

Remove all current symbols

containsSymbol

public boolean containsSymbol(Expression symbol)

Checks if a symbol is in the Select.

Parameters:

symbol - Symbol to check for

Returns:

True if the Select contains the symbol

setDistinct

public void setDistinct(boolean isDistinct)

Set whether select is distinct.

Parameters:

isDistinct - True if SELECT is distinct

isDistinct

public boolean isDistinct()

Checks whether the select is distinct

Returns:

True if select is distinct

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

getProjectedSymbols

public List<Expression> getProjectedSymbols()

Get the ordered list of all elements returned by this select. These elements may be ElementSymbols or ExpressionSymbols but in all cases each represents a single column.

Returns:

Ordered list of SingleElementSymbol

clone

public Select clone()

Return a deep copy of this Select.

Specified by:

clone in interface LanguageObject

Overrides:

clone in class Object

Returns:

Deep clone

equals

public boolean equals(Object obj)

Compare two Selects for equality. Order is important in the select (for determining the order of the returned columns), so this is a compare with order, not just a set comparison.

Overrides:

equals in class Object

Parameters:

obj - Other object

Returns:

True if equal

hashCode

public int hashCode()

Get hashcode for Select. WARNING: The hash code relies on the variables in the select, so changing the variables will change the hash code, causing a select to be lost in a hash structure. Do not hash a Select if you plan to change it.

Overrides:

hashCode in class Object

Returns:

Hash code

toString

public String toString()

Returns a string representation of an instance of this class.

Overrides:

toString in class Object

Returns:

String representation of object