org.basex.query.expr
Class CmpV

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

public final class CmpV
extends Arr

Value comparison.

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

Nested Class Summary
static class CmpV.Comp
          Comparators.
 
Nested classes/interfaces inherited from class org.basex.query.expr.Expr
Expr.Use
 
Field Summary
 CmpV.Comp cmp
          Comparator.
 
Fields inherited from class org.basex.query.expr.Arr
expr
 
Constructor Summary
CmpV(Expr e1, Expr e2, CmpV.Comp c)
          Constructor.
 
Method Summary
 Bln atomic(QueryContext ctx)
          Evaluates the expression and returns the resulting item or a null reference.
 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.
 void plan(Serializer ser)
          Recursively sends the abstract syntax of this expression to the specified serializer.
 Return returned(QueryContext ctx)
          Indicates the return type of an expression.
 String toString()
           
static boolean valCheck(Item a, Item b)
          Checks if the specified items can be compared.
 
Methods inherited from class org.basex.query.expr.Arr
duplicates, indexEquivalent, removable, remove, uses
 
Methods inherited from class org.basex.query.expr.Expr
addText, checkCtx, checkDbl, checkItr, e, ebv, i, indexAccessible, iter, 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

cmp

public CmpV.Comp cmp
Comparator.

Constructor Detail

CmpV

public CmpV(Expr e1,
            Expr e2,
            CmpV.Comp c)
Constructor.

Parameters:
e1 - first expression
e2 - second expression
c - comparator
Method Detail

comp

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

Overrides:
comp in class Arr
Parameters:
ctx - query context
Returns:
optimized Expression
Throws:
QueryException - query exception

atomic

public Bln atomic(QueryContext ctx)
           throws QueryException
Description copied from class: Expr
Evaluates the expression and returns the resulting item or a null reference. If this method is not overwritten, Expr.iter(org.basex.query.QueryContext) must be implemented.

Overrides:
atomic in class Expr
Parameters:
ctx - query context
Returns:
iterator
Throws:
QueryException - query exception

valCheck

public static boolean valCheck(Item a,
                               Item b)
Checks if the specified items can be compared.

Parameters:
a - first item
b - second item
Returns:
result of check

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.

Overrides:
plan in class Arr
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