org.basex.query.expr
Class CmpV

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

public final class CmpV
extends Arr

Value comparison.

Author:

Workgroup DBIS, University of Konstanz 2005-09, ISC License, Christian Gruen

Nested Class Summary

static class

CmpV.Comp Comparators.

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.
java.lang.String	color() Returns a string description of the expression.
Expr	comp(QueryContext ctx) Optimizes and compiles the expression.
java.lang.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.
java.lang.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

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 - evaluation 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 java.io.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:

java.io.IOException - exception

color

public java.lang.String color()

Description copied from class: ExprInfo

Returns a string description of the expression. Contrary to the ExprInfo.toString() method, the current expressions aren't included in the output.

Overrides:

color in class ExprInfo

Returns:

result of check

info

public java.lang.String info()

Description copied from class: ExprInfo

Returns a string description of the expression. Contrary to the ExprInfo.toString() method, the current expressions aren't included in the output.

Overrides:

info in class ExprInfo

Returns:

result of check

toString

public java.lang.String toString()

Specified by:

toString in class ExprInfo