Package org.basex.query.expr.gflwor

Class Condition

java.lang.Object

org.basex.query.expr.ExprInfo

org.basex.query.expr.Expr

org.basex.query.expr.ParseExpr

org.basex.query.expr.Single

org.basex.query.expr.gflwor.Condition

public final class Condition
extends Single

A window start of end condition.

Author:

BaseX Team 2005-21, BSD License, Leo Woerteler

Field Summary

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

expr

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

exprType, info

Constructor Summary

Constructors

Constructor	Description
Condition(boolean start, Var item, Var pos, Var prev, Var next, Expr cond, InputInfo info)	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.
Expr	compile(CompileContext cc)	Compiles and optimizes the expression, assigns types and cardinalities.
Condition	copy(CompileContext cc, IntObjMap<Var> vm)	Copies an expression.
boolean	equals(Object obj)	This function is e.g.
int	exprSize()	Counts the number of expressions in this expression's sub-tree.
Condition	inline(InlineContext ic)	Inlines an expression into this one, replacing all variable or context references.
Condition	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.Single

checkUp, count, has, inlineable

Methods 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, value

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

arg, args, atomItem, atomIter, data, data, ddo, funcType, hasFreeVars, indexAccessible, 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

Condition

public Condition(boolean start,
 Var item,
 Var pos,
 Var prev,
 Var next,
 Expr cond,
 InputInfo info)

Constructor.

Parameters:

start - start condition flag

item - item variable (can be null)

pos - position variable (can be null)

prev - previous variable (can be null)

next - next variable (can be null)

cond - condition

info - input info

Method Details

compile

public Expr compile(CompileContext cc)
             throws QueryException

Description copied from class: Expr

Compiles and optimizes the expression, assigns types and cardinalities.

Overrides:

compile in class Single

Parameters:

cc - compilation context

Returns:

optimized expression

Throws:

QueryException - query exception

optimize

public Condition optimize(CompileContext cc)
                   throws QueryException

Description copied from class: Expr

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

Overrides:

optimize in class Single

Parameters:

cc - compilation context

Returns:

optimized expression

Throws:

QueryException - query exception

inline

public Condition 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 Single

Parameters:

ic - inlining context

Returns:

resulting expression if something has changed, null otherwise

Throws:

QueryException - query exception

copy

public Condition 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 Expr

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 Single

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 Single

Returns:

number of expressions

equals

public boolean equals(Object obj)

Description copied from class: Single

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.

Must be overwritten by implementing class.

Overrides:

equals in class Single

plan

public void plan(QueryPlan plan)

Description copied from class: ExprInfo

Creates a query plan.

Overrides:

plan in class Single

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