Package org.basex.query.expr.path

Class AxisPath

java.lang.Object

org.basex.query.expr.ExprInfo

org.basex.query.expr.Expr

org.basex.query.expr.ParseExpr

org.basex.query.expr.path.Path

org.basex.query.expr.path.AxisPath

Direct Known Subclasses:

CachedPath, IterPath, SingleIterPath

public abstract class AxisPath
extends Path

Abstract axis path expression.

Author:

BaseX Team 2005-21, BSD License, Christian Gruen

Field Summary

Fields inherited from class org.basex.query.expr.path.Path

data, root, steps

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

exprType, info

Method Summary

Modifier and Type	Method	Description
final Expr	addPredicates(CompileContext cc, Expr... preds)	Adds predicates to the last step and returns the optimized expression.
final Data	data()	Returns the data reference bound to this expression.
final void	data(Data dt)	Assigns a data reference, if supported.
final boolean	ddo()	Indicates if this expression returns nodes in document order without duplicates.
final Iter	iter(QueryContext qc)	Evaluates the expression and returns an iterator on the resulting items.
protected abstract Iter	iterator(QueryContext qc)	Returns a node iterator.
final Expr	mergeEbv(Expr expr, boolean or, CompileContext cc)	Tries to merge two expressions that are part of an EBV test.
protected abstract Value	nodes(QueryContext qc)	Returns a node sequence.
final Step	step(int index)	Returns the specified axis step.
final Value	value(QueryContext qc)	Evaluates the expression and returns the resulting value.

Methods inherited from class org.basex.query.expr.path.Path

accept, checkUp, compile, count, equals, exprSize, get, get, has, inline, inlineable, optimize, pathNodes, plan, plan, simple, simplifyFor

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

adoptType, atomValue, checkAllUp, checkNoEmpty, checkNoEmpty, checkNoneUp, checkNoUp, checkType, checkType, checkUp, copyType, ctxValue, ebv, item, refineType, seqType, size, test, toArray, toArray, toAtomItem, toB64, toB64, toBin, toBin, toBoolean, toBoolean, toBytes, toBytes, toDouble, toDouble, toElem, toFloat, toFunc, toItem, toItem, toLong, toLong, toMap, toMap, toNode, toNode, toNodeOrNull, toNumber, toNumberOrNull, toQNm, toQNm, toToken, toToken, toTokenOrNull, toZeroToken

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

arg, args, atomItem, atomIter, copy, funcType, hasFreeVars, indexAccessible, isSimple, markTailCalls, typeCheck, uses, vacuous, visitAll

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

description, toErrorString, toString

Methods inherited from class java.lang.Object

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

Method Details

iter

public final Iter iter(QueryContext qc)
                throws QueryException

Description copied from class: Expr

Evaluates the expression and returns an iterator on the resulting items. The implementation of this method is optional.

Overrides:

iter in class ParseExpr

Parameters:

qc - query context

Returns:

iterator

Throws:

QueryException - query exception

value

public final Value value(QueryContext qc)
                  throws QueryException

Description copied from class: Expr

Evaluates the expression and returns the resulting value. If this method is not implemented, Expr.item(QueryContext, InputInfo) must be implemented instead.

Overrides:

value in class ParseExpr

Parameters:

qc - query context

Returns:

value

Throws:

QueryException - query exception

iterator

protected abstract Iter iterator(QueryContext qc)
                          throws QueryException

Returns a node iterator.

Parameters:

qc - query context

Returns:

iterator

Throws:

QueryException - query exception

nodes

protected abstract Value nodes(QueryContext qc)
                        throws QueryException

Returns a node sequence.

Parameters:

qc - query context

Returns:

iterator

Throws:

QueryException - query exception

step

public final Step step(int index)

Returns the specified axis step.

Parameters:

index - index

Returns:

step

addPredicates

public final Expr addPredicates(CompileContext cc,
 Expr... preds)
                         throws QueryException

Adds predicates to the last step and returns the optimized expression.

Parameters:

cc - compilation context

preds - predicates to be added

Returns:

new path

Throws:

QueryException - query exception

mergeEbv

public final Expr mergeEbv(Expr expr,
 boolean or,
 CompileContext cc)
                    throws QueryException

Description copied from class: Expr

Tries to merge two expressions that are part of an EBV test. Called by And, Or), Step and Filter. Overwritten by CmpG, CmpIR, CmpR, CmpSR, ItrPos, Pos and others.

Overrides:

mergeEbv in class Expr

Parameters:

expr - second expression

or - union or intersection

cc - compilation context

Returns:

optimized expression or null

Throws:

QueryException - query exception

ddo

public final boolean ddo()

Description copied from class: Expr

Indicates if this expression returns nodes in document order without duplicates.

Overrides:

ddo in class Expr

Returns:

result of check

data

public final Data data()

Description copied from class: Expr

Returns the data reference bound to this expression. This method is currently overwritten by DBNode, DBNodeSeq, AxisPath and VarRef.

Overrides:

data in class Expr

Returns:

data reference (can be null)

data

public final void data(Data dt)

Description copied from class: Expr

Assigns a data reference, if supported.

Overrides:

data in class Expr

Parameters:

dt - data reference