org.basex.query.expr
Class VarCall

java.lang.Object
  extended by org.basex.query.ExprInfo
      extended by org.basex.query.expr.Expr
          extended by org.basex.query.expr.VarCall

public final class VarCall
extends Expr

Variable expression.

Author:
Workgroup DBIS, University of Konstanz 2005-10, ISC License, Christian Gruen

Nested Class Summary
 
Nested classes/interfaces inherited from class org.basex.query.expr.Expr
Expr.Use
 
Field Summary
 Var var
          Variable name.
 
Constructor Summary
VarCall(Var v)
          Constructor.
 
Method Summary
 String color()
          Returns a color string for the expression.
 Expr comp(QueryContext ctx)
          Optimizes and compiles the expression.
 String info()
          Returns a string description of the expression.
 Iter iter(QueryContext ctx)
          Evaluates the expression and returns an iterator on the resulting items.
 void plan(Serializer ser)
          Recursively sends the abstract syntax of this expression to the specified serializer.
 boolean removable(Var v, QueryContext ctx)
          Checks if the specified variable is removable.
 Expr remove(Var v)
          Removes the specified variable in a sub expression.
 Return returned(QueryContext ctx)
          Indicates the return type of an expression.
 String toString()
           
 boolean uses(Expr.Use u, QueryContext ctx)
          Indicates if an expression uses the specified type.
 
Methods inherited from class org.basex.query.expr.Expr
addText, atomic, checkCtx, checkDbl, checkItr, duplicates, e, ebv, i, indexAccessible, indexEquivalent, sameAs, size, test, v
 
Methods inherited from class org.basex.query.ExprInfo
name
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

var

public Var var
Variable name.

Constructor Detail

VarCall

public VarCall(Var v)
Constructor.

Parameters:
v - variable
Method Detail

comp

public Expr comp(QueryContext ctx)
          throws QueryException
Description copied from class: Expr
Optimizes and compiles the expression.

Specified by:
comp in class Expr
Parameters:
ctx - query context
Returns:
optimized Expression
Throws:
QueryException - query exception

iter

public Iter iter(QueryContext ctx)
          throws QueryException
Description copied from class: Expr
Evaluates the expression and returns an iterator on the resulting items. If this method is not overwritten, Expr.atomic(org.basex.query.QueryContext) must be implemented.

Overrides:
iter in class Expr
Parameters:
ctx - query context
Returns:
resulting item
Throws:
QueryException - query exception

uses

public boolean uses(Expr.Use u,
                    QueryContext ctx)
Description copied from class: Expr
Indicates if an expression uses the specified type. Called by the compiler to perform certain optimizations. true is returned by default and thus assumed as "worst-case".

Specified by:
uses in class Expr
Parameters:
u - use type to be checked
ctx - query context
Returns:
result of check

removable

public boolean removable(Var v,
                         QueryContext ctx)
Description copied from class: Expr
Checks if the specified variable is removable.

Overrides:
removable in class Expr
Parameters:
v - variable to be removed
ctx - query context
Returns:
result of check

remove

public Expr remove(Var v)
Description copied from class: Expr
Removes the specified variable in a sub expression.

Overrides:
remove in class Expr
Parameters:
v - variable to be removed
Returns:
expression with removed variable

returned

public Return returned(QueryContext ctx)
Description copied from class: Expr
Indicates the return type of an expression. Called by the compiler to check if expressions can be reformulated. null is returned by default.

Overrides:
returned in class Expr
Parameters:
ctx - query context
Returns:
result of check

plan

public void plan(Serializer ser)
          throws IOException
Description copied from class: ExprInfo
Recursively sends the abstract syntax of this expression to the specified serializer.

Specified by:
plan in class ExprInfo
Parameters:
ser - serializer
Throws:
IOException - I/O exception

color

public String color()
Description copied from class: ExprInfo
Returns a color string for the expression.

Overrides:
color in class ExprInfo
Returns:
color

info

public String info()
Description copied from class: ExprInfo
Returns a string description of the expression. Contrary to the ExprInfo.toString() method, arguments are not included in the output.

Overrides:
info in class ExprInfo
Returns:
result of check

toString

public String toString()
Specified by:
toString in class ExprInfo