org.basex.query.xpath.expr
Class FTArrayExpr

java.lang.Object
  org.basex.query.ExprInfo
      org.basex.query.xpath.expr.Expr
          org.basex.query.xpath.expr.FTArrayExpr

Direct Known Subclasses:

FTAnd, FTIndex, FTIntersection, FTMildNot, FTMildNotIter, FTNot, FTNotIter, FTOr, FTSelect, FTUnion, FTWords

public abstract class FTArrayExpr
extends Expr

This is an abstract class for fulltext array expressions.

Author:

Workgroup DBIS, University of Konstanz 2005-08, ISC License, Christian Gruen

Field Summary

FTOpt

fto Fulltext option.

Constructor Summary

FTArrayExpr()

Method Summary

FTArrayExpr	comp(XPContext ctx) Optimizes the expression.
FTArrayExpr	indexEquivalent(XPContext ctx, Step step, boolean seq) Returns an equivalent expression which accesses an index structure.
boolean	indexOptions(MetaData meta) Verifies if the fulltext query options comply with the index defaults.
boolean	more() Checks for more results.
FTNode	next(XPContext ctx) Returns the next ftquery result.
void	plan(Serializer ser) Recursively sends the abstract syntax of this expression to the specified serializer.
boolean	pos() Checks whether the result of the expression is negative.
java.lang.String	toString()
boolean	usesPos() Checks whether this Expression (or its children) make use of the position parameter.
boolean	usesSize() Checks whether this Expression (or its children) make use of the setsize parameter.

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

eval, indexSizes, returnedValue, sameAs

Methods inherited from class org.basex.query.ExprInfo

color, info, name

Methods inherited from class java.lang.Object

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

Field Detail

fto

public FTOpt fto

Fulltext option.

Constructor Detail

FTArrayExpr

public FTArrayExpr()

Method Detail

comp

public FTArrayExpr comp(XPContext ctx)
                 throws QueryException

Optimizes the expression.

Specified by:

comp in class Expr

Parameters:

ctx - expression context

Returns:

optimized Expression

Throws:

QueryException - evaluation exception

indexOptions

public boolean indexOptions(MetaData meta)

Verifies if the fulltext query options comply with the index defaults. Check where this method is overwritten to get more info.

Parameters:

meta - meta data

Returns:

result of check

more

public boolean more()

Checks for more results.

Returns:

boolean

pos

public boolean pos()

Checks whether the result of the expression is negative.

Returns:

boolean

next

public FTNode next(XPContext ctx)

Returns the next ftquery result.

Parameters:

ctx - current context

Returns:

FTNode container for the next result

usesPos

public final boolean usesPos()

Description copied from class: Expr

Checks whether this Expression (or its children) make use of the position parameter. If not this allows some nice optimizations.

Specified by:

usesPos in class Expr

Returns:

whether position is used

usesSize

public final boolean usesSize()

Description copied from class: Expr

Checks whether this Expression (or its children) make use of the setsize parameter. If not this allows early predicate evaluation.

Specified by:

usesSize in class Expr

Returns:

whether setsize is used

indexEquivalent

public FTArrayExpr indexEquivalent(XPContext ctx,
                                   Step step,
                                   boolean seq)
                            throws QueryException

Description copied from class: Expr

Returns an equivalent expression which accesses an index structure.

Overrides:

indexEquivalent in class Expr

Parameters:

ctx - root

step - location step

seq - flag for sequential evaluation

Returns:

Equivalent index-expression or null

Throws:

QueryException - evaluation exception

toString

public java.lang.String toString()

Specified by:

toString in class ExprInfo

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.

Specified by:

plan in class ExprInfo

Parameters:

ser - serializer

Throws:

java.io.IOException - exception