org.basex.query.expr

Class CName

java.lang.Object

org.basex.data.ExprInfo

org.basex.query.expr.Expr

org.basex.query.expr.ParseExpr

org.basex.query.expr.Arr

org.basex.query.expr.CFrag

org.basex.query.expr.CName

Direct Known Subclasses:

CAttr, CElem, CNSpace, CPI

public abstract class CName
extends CFrag

Abstract fragment constructor with a QName argument.

Author:

BaseX Team 2005-12, BSD License, Christian Gruen

Nested Class Summary

Nested classes/interfaces inherited from class org.basex.query.expr.Expr

Expr.Use

Field Summary

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

expr

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

input, size, type

Method Summary

Methods

Modifier and Type	Method and Description
CName	comp(QueryContext ctx) Compiles and optimizes the expression, assigns data types and cardinalities.
int	count(Var v) Counts how often the specified variable is used by an expression.
java.lang.String	description() Returns a string description of the expression.
void	plan(Serializer ser) Serializes the expression tree.
Expr	remove(Var v) Substitutes all VarRef expressions for the given variable by a Context reference.
java.lang.String	toString()
boolean	uses(Expr.Use u) Indicates if an expression uses the specified type or operation.

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

item, toString

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

allAreValues, indexEquivalent, removable

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

checkBln, checkColl, checkCreate, checkCtx, checkDbl, checkDBNode, checkEStr, checkEStr, checkIO, checkItem, checkItr, checkItr, checkMap, checkNode, checkNoEmpty, checkStr, checkType, checkUp, checkUp, checkWrite, compBln, ebv, iter, optPre, preEval, size, test, type, value

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

addText, compEbv, hasFreeVars, indexAccessible, isEmpty, isFunction, isItem, isVacuous, isValue, iterable, markTailCalls, sameAs

Methods inherited from class org.basex.data.ExprInfo

info

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

comp

public CName comp(QueryContext ctx)
           throws QueryException

Description copied from class: Expr

Compiles and optimizes the expression, assigns data types and cardinalities.

Overrides:

comp in class Arr

Parameters:

ctx - query context

Returns:

optimized expression

Throws:

QueryException - query exception

remove

public final Expr remove(Var v)

Description copied from class: Expr

Substitutes all VarRef expressions for the given variable by a Context reference. This method is called by GFLWOR.comp(org.basex.query.QueryContext) to rewrite where clauses as predicates.

Overrides:

remove in class Arr

Parameters:

v - variable to be replaced

Returns:

new expression

uses

public final boolean uses(Expr.Use u)

Description copied from class: Expr

Indicates if an expression uses the specified type or operation. This method is called by numerous Expr.comp(org.basex.query.QueryContext) methods to test the properties of sub-expressions. It will return true as soon as at least one test is successful.

Overrides:

uses in class CFrag

Parameters:

u - type/operation to be found

Returns:

result of check

count

public final int count(Var v)

Description copied from class: Expr

Counts how often the specified variable is used by an expression. This method is called by:

• GFLWOR.comp(org.basex.query.QueryContext) to rewrite where clauses as predicates and remove statically bound or unused clauses
• GFLWOR.compHoist(org.basex.query.QueryContext) to hoist independent variables

Overrides:

count in class Arr

Parameters:

v - variable to be checked

Returns:

number of occurrences

plan

public final void plan(Serializer ser)
                throws java.io.IOException

Description copied from class: ExprInfo

Serializes the expression tree.

Overrides:

plan in class Arr

Parameters:

ser - serializer

Throws:

java.io.IOException - I/O exception

description

public final java.lang.String description()

Description copied from class: ExprInfo

Returns a string description of the expression. This method is only called by error messages. Contrary to the ExprInfo.toString() method, arguments are not included in the output.

Overrides:

description in class ExprInfo

Returns:

result of check

toString

public final java.lang.String toString()

Specified by:

toString in class ExprInfo