public final class GroupBy extends GFLWOR.Clause
group by
expression.Modifier and Type | Class and Description |
---|---|
static class |
GroupBy.Spec
Grouping spec.
|
Constructor and Description |
---|
GroupBy(GroupBy.Spec[] specs,
VarRef[] pre,
Var[] post,
InputInfo info)
Constructor.
|
Modifier and Type | Method and 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 all updating expressions are correctly placed.
|
GroupBy |
compile(QueryContext qc,
VarScope sc)
Compiles and optimizes the expression, assigns types and cardinalities.
|
GroupBy |
copy(QueryContext qc,
VarScope scp,
IntObjMap<Var> vs)
Copies an expression.
|
VarUsage |
count(Var var)
Checks how often a variable is used in this expression.
|
int |
exprSize()
Counts the number of expressions in this expression's sub-tree.
|
boolean |
has(Expr.Flag flag)
Indicates if an expression has the specified compiler property.
|
GFLWOR.Clause |
inline(QueryContext qc,
VarScope scp,
Var var,
Expr ex)
Inlines an expression into this one, replacing all references to the given variable.
|
GroupBy |
optimize(QueryContext qc,
VarScope scp)
Optimizes an already compiled expression without recompiling its sub-expressions.
|
void |
plan(FElem plan)
Creates an expression tree.
|
boolean |
removable(Var var)
Checks if the specified variable is replaceable by a context value.
|
String |
toString() |
declares, item, iter, value, vars
atomItem, atomValue, checkAtomic, checkNoEmpty, checkNoEmpty, checkNoneUp, checkNoUp, checkType, compBln, copyType, ctxValue, ebv, optPre, optPre, preEval, seqType, seqType, size, test, toArray, toArray, toAtomItem, toB64, toB64, toBin, toBin, toBoolean, toBoolean, toBytes, toBytes, toDouble, toDouble, toElem, toEmptyNode, toEmptyToken, toFloat, toFunc, toItem, toLong, toLong, toMap, toMap, toNode, toNode, toNumber, toQNm, toQNm, toToken, toToken
atomIter, data, hasFreeVars, indexAccessible, inlineAll, isEmpty, isFunction, isVacuous, isValue, iterable, markTailCalls, optimizeEbv, sameAs, typeCheck, uses, visitAll
addPlan, addPlan, description, planAttr, planElem, toErrorString
public GroupBy(GroupBy.Spec[] specs, VarRef[] pre, Var[] post, InputInfo info)
specs
- grouping specspre
- references to pre-grouping variablespost
- post-grouping variablesinfo
- input infopublic boolean has(Expr.Flag flag)
Expr
true
if at least one test is successful.public GroupBy compile(QueryContext qc, VarScope sc) throws QueryException
Expr
QueryContext.compile()
.compile
in class GFLWOR.Clause
qc
- query contextsc
- variable scopeQueryException
- query exceptionpublic GroupBy optimize(QueryContext qc, VarScope scp) throws QueryException
Expr
optimize
in class GFLWOR.Clause
qc
- query contextscp
- variable scopeQueryException
- query exceptionpublic boolean removable(Var var)
Expr
Preds.removable(org.basex.query.var.Var)
if one of the variables is used within a predicate.Path.removable(org.basex.query.var.Var)
if the variable occurs within the path.GFLWOR.compile(QueryContext, VarScope)
to rewrite where
clauses into predicates.public VarUsage count(Var var)
Expr
SwitchCase.countCases(org.basex.query.var.Var)
or (indirectly)
GFLWOR.inlineLets(org.basex.query.QueryContext, org.basex.query.var.VarScope)
.public GFLWOR.Clause inline(QueryContext qc, VarScope scp, Var var, Expr ex) throws QueryException
Expr
GFLWOR.inlineLets(org.basex.query.QueryContext, org.basex.query.var.VarScope)
and For.toPredicate(org.basex.query.QueryContext, org.basex.query.var.VarScope, org.basex.query.expr.Expr)
,
and the variable reference is replaced in VarRef.inline(org.basex.query.QueryContext, org.basex.query.var.VarScope, org.basex.query.var.Var, org.basex.query.expr.Expr)
.inline
in class GFLWOR.Clause
qc
- query context for reoptimizationscp
- variable scope for reoptimizationvar
- variable to replaceex
- expression to inlinenull
otherwiseQueryException
- query exceptionpublic GroupBy copy(QueryContext qc, VarScope scp, IntObjMap<Var> vs)
Expr
copy
in class GFLWOR.Clause
qc
- query contextscp
- variable scope for creating new variablesvs
- mapping from old variable IDs to new variable copiespublic boolean accept(ASTVisitor visitor)
Expr
public void checkUp() throws QueryException
Expr
checkUp
in class Expr
QueryException
- query exceptionpublic int exprSize()
Expr
StaticFunc.inline(org.basex.query.QueryContext, org.basex.query.util.list.AnnList, org.basex.query.expr.Expr)
to check if an expression
is small enough to be inlined.public void plan(FElem plan)
ExprInfo
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