org.basex.query.expr
Class Cast

java.lang.Object
  org.basex.query.ExprInfo
      org.basex.query.expr.Expr
          org.basex.query.expr.Single
              org.basex.query.expr.Cast

public final class Cast
extends Single

Cast expression.

Author:

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

Field Summary

Fields inherited from class org.basex.query.expr.Single

expr

Constructor Summary

Cast(Expr e, SeqType t)
Function constructor.

Method Summary

Item	atomic(QueryContext ctx) Evaluates the expression and returns the resulting item or a null reference.
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()

Methods inherited from class org.basex.query.expr.Single

remove, uses

Methods inherited from class org.basex.query.expr.Expr

addText, checkCtx, checkDbl, checkItr, duplicates, e, ebv, i, indexAccessible, indexEquivalent, iter, removable, sameAs, size, test

Methods inherited from class org.basex.query.ExprInfo

color, name

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Cast

public Cast(Expr e,
            SeqType t)

Function constructor.

Parameters:

e - expression

t - data type

Method Detail

comp

public Expr comp(QueryContext ctx)
          throws QueryException

Description copied from class: Expr

Optimizes and compiles the expression.

Overrides:

comp in class Single

Parameters:

ctx - query context

Returns:

optimized Expression

Throws:

QueryException - evaluation exception

atomic

public Item 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

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 Single

Parameters:

ser - serializer

Throws:

java.io.IOException - exception

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

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