org.basex.query.expr
Class Arr

java.lang.Object
  extended by org.basex.data.ExprInfo
      extended by org.basex.query.expr.Expr
          extended by org.basex.query.expr.ParseExpr
              extended by org.basex.query.expr.Arr
Direct Known Subclasses:
Arith, CFrag, Cmp, Delete, DynFuncCall, Except, If, Insert, InterSect, JavaMapping, List, LitMap, Logical, PartFunc, Range, Rename, Replace, StandardFunc, StaticFuncCall, SwitchCase, Transform, Union

public abstract class Arr
extends ParseExpr

Abstract array expression.

Author:
BaseX Team 2005-12, BSD License, Christian Gruen

Nested Class Summary
 
Nested classes/interfaces inherited from class org.basex.query.expr.Expr
Expr.Flag
 
Field Summary
 Expr[] expr
          Expression list.
 
Fields inherited from class org.basex.query.expr.ParseExpr
info, size, type
 
Constructor Summary
protected Arr(InputInfo ii, Expr... e)
          Constructor.
 
Method Summary
 boolean accept(ASTVisitor visitor)
          Traverses this expression, notifying the visitor of declared and used variables, and checking the tree for other recursive properties.
protected  boolean allAreValues()
          Returns true if all arguments are values.
 void checkNoUp()
          Checks if none of the expressions are updating expressions.
 void checkUp()
          Checks if all updating expressions are correctly placed.
 Expr compile(QueryContext ctx, VarScope scp)
          Compiles and optimizes the expression, assigns data types and cardinalities.
static
<T extends Expr>
T[]
copyAll(QueryContext ctx, VarScope scp, IntObjMap<Var> vs, T[] arr)
          Creates a deep copy of the given array.
 VarUsage count(Var v)
          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.
 Expr indexEquivalent(IndexCosts ic)
          Returns an equivalent expression which accesses an index structure.
 Expr inline(QueryContext ctx, VarScope scp, Var v, Expr e)
          Inlines an expression into this one, replacing all references to the given variable.
 void plan(FElem plan)
          Creates an expression tree.
 boolean removable(Var v)
          Checks if the specified variable is replaceable by a context item.
protected  java.lang.String toString(java.lang.String sep)
          Prints the array with the specified separator.
 
Methods inherited from class org.basex.query.expr.ParseExpr
checkAdmin, checkAllUp, checkBinary, checkBln, checkColl, checkCreate, checkCtx, checkDbl, checkDBNode, checkEStr, checkEStr, checkFunc, checkItem, checkItr, checkItr, checkMap, checkNode, checkNode, checkNode, checkNoEmpty, checkNoneUp, checkNoUp, checkQNm, checkStr, checkStr, checkStrBin, checkType, checkWrite, compBln, copyType, ebv, item, iter, optPre, preEval, size, test, type, value
 
Methods inherited from class org.basex.query.expr.Expr
addText, compEbv, copy, copy, hasFreeVars, indexAccessible, inlineAll, isEmpty, isFunction, isItem, isVacuous, isValue, iterable, markTailCalls, optimize, sameAs, uses, visitAll
 
Methods inherited from class org.basex.data.ExprInfo
addPlan, addPlan, description, info, planAttr, planElem, toString
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

expr

public Expr[] expr
Expression list.

Constructor Detail

Arr

protected Arr(InputInfo ii,
              Expr... e)
Constructor.

Parameters:
ii - input info
e - expression list
Method Detail

checkUp

public void checkUp()
             throws QueryException
Description copied from class: Expr
Checks if all updating expressions are correctly placed. This function is only called if any updating expression was found in the query.

Specified by:
checkUp in class Expr
Throws:
QueryException - query exception

compile

public Expr compile(QueryContext ctx,
                    VarScope scp)
             throws QueryException
Description copied from class: Expr
Compiles and optimizes the expression, assigns data types and cardinalities.

Specified by:
compile in class Expr
Parameters:
ctx - query context
scp - variable scope
Returns:
optimized expression
Throws:
QueryException - query exception

has

public boolean has(Expr.Flag flag)
Description copied from class: Expr
Indicates if an expression has the specified compiler property. This method is called by numerous Expr.compile(org.basex.query.QueryContext, org.basex.query.var.VarScope) methods to test properties of sub-expressions. It returns true if at least one test is successful.

Specified by:
has in class Expr
Parameters:
flag - flag to be found
Returns:
result of check

removable

public boolean removable(Var v)
Description copied from class: Expr
Checks if the specified variable is replaceable by a context item. The following tests might return false: This method is called by GFLWOR.compile(org.basex.query.QueryContext, org.basex.query.var.VarScope) to rewrite where clauses into predicates.

Specified by:
removable in class Expr
Parameters:
v - variable to be replaced
Returns:
result of check

count

public VarUsage count(Var v)
Description copied from class: Expr
Checks how often a variable is used in this expression.

Specified by:
count in class Expr
Parameters:
v - variable to look for
Returns:
how often the variable is used, see VarUsage

inline

public Expr inline(QueryContext ctx,
                   VarScope scp,
                   Var v,
                   Expr e)
            throws QueryException
Description copied from class: Expr
Inlines an expression into this one, replacing all references to the given variable.

Specified by:
inline in class Expr
Parameters:
ctx - query context for recompilation
scp - variable scope for recompilation
v - variable to replace
e - expression to inline
Returns:
resulting expression in something changed, null otherwise
Throws:
QueryException - query exception

copyAll

public static final <T extends Expr> T[] copyAll(QueryContext ctx,
                                                 VarScope scp,
                                                 IntObjMap<Var> vs,
                                                 T[] arr)
Creates a deep copy of the given array.

Type Parameters:
T - element type
Parameters:
ctx - query context
scp - variable scope
vs - variable mapping
arr - array to copy
Returns:
deep copy of the array

indexEquivalent

public Expr indexEquivalent(IndexCosts ic)
                     throws QueryException
Description copied from class: Expr
Returns an equivalent expression which accesses an index structure. Will be called if Expr.indexAccessible(org.basex.query.util.IndexCosts) is returns true for an expression.

Overrides:
indexEquivalent in class Expr
Parameters:
ic - index costs analyzer
Returns:
equivalent index-expression
Throws:
QueryException - query exception

allAreValues

protected final boolean allAreValues()
Returns true if all arguments are values.

Returns:
result of check

checkNoUp

public final void checkNoUp()
                     throws QueryException
Checks if none of the expressions are updating expressions.

Throws:
QueryException - query exception

plan

public void plan(FElem plan)
Description copied from class: ExprInfo
Creates an expression tree.

Specified by:
plan in class ExprInfo
Parameters:
plan - root element

toString

protected java.lang.String toString(java.lang.String sep)
Prints the array with the specified separator.

Parameters:
sep - separator
Returns:
string representation

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.

Specified by:
accept in class Expr
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.

Specified by:
exprSize in class Expr
Returns:
number of expressions