Package org.basex.query.expr
Class Filter
- Direct Known Subclasses:
CachedFilter,IterFilter
Abstract filter expression.
- Author:
- BaseX Team 2005-21, BSD License, Christian Gruen
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Field Summary
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionfinal booleanaccept(ASTVisitor visitor) Traverses this expression, notifying the visitor of declared and used variables, and checking the tree for other recursive properties.final ExpraddPredicate(CompileContext cc, Expr pred) Adds a predicate and returns the optimized expression.final voidcheckUp()Checks if the updating semantics are satisfied.final ExprCompiles and optimizes the expression, assigns types and cardinalities.final VarUsageChecks how often a variable or context reference is used in this expression.final Datadata()Returns the data reference bound to this expression.booleanddo()Indicates if this expression returns nodes in document order without duplicates.final booleanThis function is e.g.final intexprSize()Counts the number of expressions in this expression's sub-tree.static Exprget(CompileContext cc, InputInfo ii, Expr root, Expr... preds) Creates a new, optimized filter expression, or the root expression if no predicates exist.final booleanIndicates if an expression has one of the specified compiler properties.final Exprinline(InlineContext ic) Inlines an expression into this one, replacing all variable or context references.final booleanChecks if inlining is possible.final ExprOptimizes an already compiled expression without recompiling its sub-expressions.final voidCreates a query plan.final voidplan(QueryString qs) Creates a query string.final ExprRewrites a filter expression for count operations.final ExprsimplifyFor(CompileContext.Simplify mode, CompileContext cc) This function is called at compile time for expressions whose operands might be simplified.protected final voidAssigns the expression type.Methods inherited from class org.basex.query.expr.Preds
flattenEbv, match, mayBePositional, numeric, simplifyMethods inherited from class org.basex.query.expr.Arr
allAreValues, args, copyAll, flatten, inline, mayBePositional, simplifyAllMethods inherited from class org.basex.query.expr.ParseExpr
adoptType, atomValue, checkAllUp, checkNoEmpty, checkNoEmpty, checkNoneUp, checkNoUp, checkType, checkType, checkUp, copyType, ctxValue, ebv, item, iter, 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, valueMethods inherited from class org.basex.query.expr.Expr
arg, atomItem, atomIter, copy, data, funcType, hasFreeVars, indexAccessible, isSimple, markTailCalls, mergeEbv, typeCheck, uses, vacuous, visitAllMethods inherited from class org.basex.query.expr.ExprInfo
description, toErrorString, toString
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Field Details
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root
Expression.
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Constructor Details
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Filter
Constructor.- Parameters:
info- input inforoot- root expressionexprs- predicate expressions
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Method Details
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get
public static Expr get(CompileContext cc, InputInfo ii, Expr root, Expr... preds) throws QueryException Creates a new, optimized filter expression, or the root expression if no predicates exist.- Parameters:
cc- compilation contextii- input inforoot- root expressionpreds- predicate expressions- Returns:
- filter root, path or filter expression
- Throws:
QueryException- query exception
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checkUp
Description copied from class:ExprChecks if the updating semantics are satisfied. This function is only called if any updating expression was found in the query.- Overrides:
checkUpin classArr- Throws:
QueryException- query exception
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compile
Description copied from class:ExprCompiles and optimizes the expression, assigns types and cardinalities.- Overrides:
compilein classPreds- Parameters:
cc- compilation context- Returns:
- optimized expression
- Throws:
QueryException- query exception
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optimize
Description copied from class:ExprOptimizes an already compiled expression without recompiling its sub-expressions.- Overrides:
optimizein classExpr- Parameters:
cc- compilation context- Returns:
- optimized expression
- Throws:
QueryException- query exception
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type
Description copied from class:PredsAssigns the expression type. -
addPredicate
Adds a predicate and returns the optimized expression. This function is e.g. called byForLet.addPredicate(org.basex.query.CompileContext, org.basex.query.expr.Expr).- Parameters:
cc- compilation contextpred- predicate to be added- Returns:
- new filter
- Throws:
QueryException- query exception
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simplifyCount
Rewrites a filter expression for count operations.- Parameters:
cc- compilation context- Returns:
- optimized or original expression.
- Throws:
QueryException- query exception
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simplifyFor
public final Expr simplifyFor(CompileContext.Simplify mode, CompileContext cc) throws QueryException Description copied from class:ExprThis function is called at compile time for expressions whose operands might be simplified.- Overrides:
simplifyForin classExpr- Parameters:
mode- mode of simplificationcc- compilation context- Returns:
- simplified or original expression
- Throws:
QueryException- query exception- See Also:
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has
Description copied from class:ExprIndicates 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 returnstrueif at least flag matches an expression. -
inlineable
Description copied from class:ExprChecks if inlining is possible. This function is called byInlineContext.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:- Overrides:
inlineablein classPreds- Parameters:
ic- inlining context- Returns:
- result of check
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count
Description copied from class:ExprChecks 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)
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inline
Description copied from class:ExprInlines an expression into this one, replacing all variable or context references. This function is called byInlineContext.inline(Expr)(see invocations of this functions for further inlinings). The variable reference is replaced in: The context is replaced in:- Overrides:
inlinein classArr- Parameters:
ic- inlining context- Returns:
- resulting expression if something has changed,
nullotherwise - Throws:
QueryException- query exception
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data
Description copied from class:Expr -
accept
Description copied from class:ExprTraverses this expression, notifying the visitor of declared and used variables, and checking the tree for other recursive properties. -
ddo
public boolean ddo()Description copied from class:ExprIndicates if this expression returns nodes in document order without duplicates. -
exprSize
public final int exprSize()Description copied from class:ExprCounts the number of expressions in this expression's sub-tree. This method is e.g. called byStaticFunc.inline(org.basex.query.expr.Expr[], org.basex.query.CompileContext)to check if an expression is small enough to be inlined. -
equals
Description copied from class:ArrThis function is e.g. called by:Must be overwritten by implementing class.If.optimize(CompileContext),Switch.optimize(CompileContext),Typeswitch.optimize(CompileContext), in order to discard identical expressions.CmpR.mergeEbv(Expr, boolean, CompileContext)orCmpSR.mergeEbv(Expr, boolean, CompileContext), in order to merge expressions with identical input.CmpG.optimize(CompileContext)orCmpV.optimize(CompileContext), in order to pre-evaluate equality tests.CmpG.optimize(CompileContext)orPos.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.
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plan
Description copied from class:ExprInfoCreates a query plan. -
plan
Description copied from class:ExprInfoCreates a query string.
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