org.basex.query.ft

Class FTIndexAccess

java.lang.Object

org.basex.data.ExprInfo

org.basex.query.expr.Expr

org.basex.query.expr.ParseExpr

org.basex.query.expr.Simple

org.basex.query.ft.FTIndexAccess

public final class FTIndexAccess
extends Simple

FTContains expression with index access.

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.ParseExpr

input, size, type

Constructor Summary

Constructors

Constructor and Description
FTIndexAccess(InputInfo ii, FTExpr ex, IndexContext ic) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
int	count(Var v) Counts how often the specified variable is used by an expression.
NodeIter	iter(QueryContext ctx) Evaluates the expression and returns an iterator on the resulting items.
boolean	iterable() Returns true if the expression is iterable, i.e., if it does not contain any duplicates and if all results are sorted.
void	plan(Serializer ser) Serializes the expression tree.
boolean	removable(Var v) Checks if the specified variable is replaceable by a context item.
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.Simple

comp

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, item, optPre, preEval, size, test, type, value

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

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

Methods inherited from class org.basex.data.ExprInfo

description, info

Methods inherited from class java.lang.Object

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

Constructor Detail

FTIndexAccess

public FTIndexAccess(InputInfo ii,
             FTExpr ex,
             IndexContext ic)

Constructor.

Parameters:

ii - input info

ex - contains, select and optional ignore expression

ic - index context

Method Detail

iter

public NodeIter 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.item(org.basex.query.QueryContext, org.basex.util.InputInfo) must be implemented by an expression, as it may be called by this method.

Overrides:

iter in class ParseExpr

Parameters:

ctx - query context

Returns:

resulting item

Throws:

QueryException - query exception

uses

public 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 Simple

Parameters:

u - type/operation to be found

Returns:

result of check

count

public 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 Simple

Parameters:

v - variable to be checked

Returns:

number of occurrences

removable

public boolean removable(Var v)

Description copied from class: Expr

Checks if the specified variable is replaceable by a context item. The following tests might return false:

• Preds.removable(org.basex.query.util.Var), if one of the variables is used within a predicate.
• MixedPath.removable(org.basex.query.util.Var), if the variable occurs within the path.
• Group.removable(org.basex.query.util.Var), as the group by expression depends on variable references.

This method is called by GFLWOR.comp(org.basex.query.QueryContext) to rewrite where clauses into predicates.

Overrides:

removable in class Simple

Parameters:

v - variable to be replaced

Returns:

result of check

remove

public 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 Simple

Parameters:

v - variable to be replaced

Returns:

new expression

plan

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

Description copied from class: ExprInfo

Serializes the expression tree.

Overrides:

plan in class Simple

Parameters:

ser - serializer

Throws:

java.io.IOException - I/O exception

iterable

public boolean iterable()

Description copied from class: Expr

Returns true if the expression is iterable, i.e., if it does not contain any duplicates and if all results are sorted. This method is called e.g. by AxisPath.

Overrides:

iterable in class Expr

Returns:

result of check

toString

public java.lang.String toString()

Specified by:

toString in class ExprInfo