Package org.basex.query.expr.ft

Class FTWeight

java.lang.Object

org.basex.query.expr.ExprInfo

org.basex.query.expr.Expr

org.basex.query.expr.ParseExpr

org.basex.query.expr.ft.FTExpr

org.basex.query.expr.ft.FTWeight

public final class FTWeight
extends FTExpr

FTOptions expression.

Author:

BaseX Team 2005-21, BSD License, Christian Gruen

Field Summary

Fields inherited from class org.basex.query.expr.ft.FTExpr

exprs

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

exprType, info

Constructor Summary

Constructors

Constructor	Description
FTWeight(InputInfo info, FTExpr expr, Expr weight)	Constructor.

Method Summary

Modifier and Type	Method	Description
boolean	accept(ASTVisitor visitor)	Traverses this expression, notifying the visitor of declared and used variables, and checking the tree for other recursive properties.
void	checkUp()	Checks if the updating semantics are satisfied.
FTExpr	compile(CompileContext cc)	Compiles and optimizes the expression, assigns types and cardinalities.
FTExpr	copy(CompileContext cc, IntObjMap<Var> vm)	Copies an expression.
VarUsage	count(Var var)	Checks how often a variable or context reference is used in this expression.
boolean	equals(Object obj)	This function is e.g.
int	exprSize()	Counts the number of expressions in this expression's sub-tree.
boolean	has(Flag... flags)	Indicates if an expression has one of the specified compiler properties.
boolean	indexAccessible(IndexInfo ii)	Checks if an expression can be rewritten to an index access.
FTExpr	inline(InlineContext ic)	Inlines an expression into this one, replacing all variable or context references.
boolean	inlineable(InlineContext ic)	Checks if inlining is possible.
FTNode	item(QueryContext qc, InputInfo ii)	This method is called by the sequential full-text evaluation.
FTIter	iter(QueryContext qc)	This method is called by the index-based full-text evaluation.
FTExpr	optimize(CompileContext cc)	Optimizes an already compiled expression without recompiling its sub-expressions.
void	plan(QueryPlan plan)	Creates a query plan.
void	plan(QueryString qs)	Creates a query string.

Methods inherited from class org.basex.query.expr.ft.FTExpr

usesExclude, value

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

adoptType, atomValue, checkAllUp, checkNoEmpty, checkNoEmpty, checkNoneUp, checkNoUp, checkType, checkType, checkUp, copyType, ctxValue, ebv, 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, data, data, ddo, funcType, hasFreeVars, isSimple, markTailCalls, mergeEbv, simplifyFor, 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

Constructor Details

FTWeight

public FTWeight(InputInfo info,
 FTExpr expr,
 Expr weight)

Constructor.

Parameters:

info - input info

expr - expression

weight - weight

Method Details

checkUp

public void checkUp()
             throws QueryException

Description copied from class: Expr

Checks if the updating semantics are satisfied. This function is only called if any updating expression was found in the query.

Overrides:

checkUp in class FTExpr

Throws:

QueryException - query exception

compile

public FTExpr compile(CompileContext cc)
               throws QueryException

Description copied from class: Expr

Compiles and optimizes the expression, assigns types and cardinalities.

Overrides:

compile in class FTExpr

Parameters:

cc - compilation context

Returns:

optimized expression

Throws:

QueryException - query exception

optimize

public FTExpr optimize(CompileContext cc)
                throws QueryException

Description copied from class: Expr

Optimizes an already compiled expression without recompiling its sub-expressions.

Overrides:

optimize in class FTExpr

Parameters:

cc - compilation context

Returns:

optimized expression

Throws:

QueryException - query exception

item

public FTNode item(QueryContext qc,
 InputInfo ii)
            throws QueryException

Description copied from class: FTExpr

This method is called by the sequential full-text evaluation. It always returns an item.

Specified by:

item in class FTExpr

Parameters:

qc - query context

ii - input info (only required by Seq instances, which have no input info)

Returns:

resulting item

Throws:

QueryException - query exception

iter

public FTIter iter(QueryContext qc)

Description copied from class: FTExpr

This method is called by the index-based full-text evaluation.

Specified by:

iter in class FTExpr

Parameters:

qc - query context

Returns:

resulting item

indexAccessible

public boolean indexAccessible(IndexInfo ii)

Description copied from class: Expr

Checks if an expression can be rewritten to an index access. If so, the index expression will be bound to IndexInfo.expr. This method will be called by the Path expression.

Overrides:

indexAccessible in class Expr

Parameters:

ii - index info

Returns:

true if an index can be used

has

public boolean has(Flag... flags)

Description copied from class: Expr

Indicates if an expression has one of the specified compiler properties. This method must only be called at compile time. It is invoked to test properties of sub-expressions. It returns true if at least flag matches an expression.

Overrides:

has in class FTExpr

Parameters:

flags - flags to be checked

Returns:

result of check

inlineable

public boolean inlineable(InlineContext ic)

Description copied from class: Expr

Checks if inlining is possible. This function is called by InlineContext.inlineable(org.basex.query.expr.Expr...) and: CNode.inlineable(org.basex.query.InlineContext) returns false if the new expression construct new nodes. The following tests might reject inlining if the expression is a context reference:

• Preds.inlineable(org.basex.query.InlineContext)
• Path.inlineable(org.basex.query.InlineContext)
• SimpleMap.inlineable(org.basex.query.InlineContext)
• StaticJavaCall.inlineable(org.basex.query.InlineContext)
• TransformWith.inlineable(org.basex.query.InlineContext)

Overrides:

inlineable in class FTExpr

Parameters:

ic - inlining context

Returns:

result of check

count

public VarUsage count(Var var)

Description copied from class: Expr

Checks how often a variable or context reference is used in this expression. This function is called by:

• Closure.optimize(org.basex.query.CompileContext)
• GFLWOR.inlineForLet(org.basex.query.CompileContext)
• GFLWOR.optimizePos(org.basex.query.CompileContext)
• GFLWOR.simplify(org.basex.query.CompileContext)
• GFLWOR.unusedVars(org.basex.query.CompileContext)
• SimpleMap.optimize(org.basex.query.CompileContext)
• TypeswitchGroup.optimize(org.basex.query.CompileContext)

Overrides:

count in class FTExpr

Parameters:

var - variable (Var reference) or context (null) to inline

Returns:

number of usages, see VarUsage

inline

public FTExpr inline(InlineContext ic)
              throws QueryException

Description copied from class: Expr

Inlines an expression into this one, replacing all variable or context references. This function is called by InlineContext.inline(Expr) (see invocations of this functions for further inlinings). The variable reference is replaced in:

• OrderBy.inline(org.basex.query.InlineContext)
• VarRef.inline(org.basex.query.InlineContext)

The context is replaced in:

• ContextFn.inline(org.basex.query.InlineContext)
• ContextValue.inline(org.basex.query.InlineContext)
• Arr.inline(org.basex.query.InlineContext)

Overrides:

inline in class FTExpr

Parameters:

ic - inlining context

Returns:

resulting expression if something has changed, null otherwise

Throws:

QueryException - query exception

copy

public FTExpr copy(CompileContext cc,
 IntObjMap<Var> vm)

Description copied from class: Expr

Copies an expression. Used for inlining functions, or for copying static queries. It is utilized by VarRef.inline(org.basex.query.InlineContext), FuncItem.inline(org.basex.query.expr.Expr[], org.basex.query.CompileContext), Closure.inline(org.basex.query.InlineContext) and StaticFunc.inline(org.basex.query.expr.Expr[], org.basex.query.CompileContext).

Specified by:

copy in class FTExpr

Parameters:

cc - compilation context

vm - mapping from old variable IDs to new variable copies. Required by Closure.copy(org.basex.query.CompileContext, org.basex.util.hash.IntObjMap<org.basex.query.var.Var>) and VarRef.copy(org.basex.query.CompileContext, org.basex.util.hash.IntObjMap<org.basex.query.var.Var>)

Returns:

copied expression

accept

public boolean accept(ASTVisitor visitor)

Description copied from class: Expr

Traverses this expression, notifying the visitor of declared and used variables, and checking the tree for other recursive properties.

Overrides:

accept in class FTExpr

Parameters:

visitor - visitor

Returns:

if the walk should be continued

exprSize

public int exprSize()

Description copied from class: Expr

Counts the number of expressions in this expression's sub-tree. This method is e.g. called by StaticFunc.inline(org.basex.query.expr.Expr[], org.basex.query.CompileContext) to check if an expression is small enough to be inlined.

Overrides:

exprSize in class FTExpr

Returns:

number of expressions

equals

public boolean equals(Object obj)

Description copied from class: Expr

This function is e.g. called by:

• If.optimize(CompileContext), Switch.optimize(CompileContext), Typeswitch.optimize(CompileContext), in order to discard identical expressions.
• CmpR.mergeEbv(Expr, boolean, CompileContext) or CmpSR.mergeEbv(Expr, boolean, CompileContext), in order to merge expressions with identical input.
• CmpG.optimize(CompileContext) or CmpV.optimize(CompileContext), in order to pre-evaluate equality tests.
• CmpG.optimize(CompileContext) or Pos.get(Expr, CmpV.OpV, InputInfo, CompileContext), in order to compare the start and end value.
• PathCache, in order to find identical root values at runtime.

Overrides:

equals in class FTExpr

plan

public void plan(QueryPlan plan)

Description copied from class: ExprInfo

Creates a query plan.

Overrides:

plan in class FTExpr

Parameters:

plan - expression plan

plan

public void plan(QueryString qs)

Description copied from class: ExprInfo

Creates a query string.

Specified by:

plan in class ExprInfo

Parameters:

qs - query string builder