org.basex.query.expr
Class Extension

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.Single
                  extended by org.basex.query.expr.Extension

public final class Extension
extends Single

Pragma extension.

Author:
BaseX Team 2005-12, BSD License, Leo Woerteler

Nested Class Summary
 
Nested classes/interfaces inherited from class org.basex.query.expr.Expr
Expr.Flag
 
Field Summary
 
Fields inherited from class org.basex.query.expr.Single
expr
 
Fields inherited from class org.basex.query.expr.ParseExpr
info, size, type
 
Constructor Summary
Extension(InputInfo ii, Pragma[] prag, Expr e)
          Constructor.
 
Method Summary
 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.
 Expr copy(QueryContext ctx, VarScope scp, IntObjMap<Var> vs)
          Copies an expression.
 ValueIter iter(QueryContext ctx)
          Evaluates the expression and returns an iterator on the resulting items.
 Expr markTailCalls()
          Finds and marks tail calls, enabling TCO.
 void plan(FElem plan)
          Creates an expression tree.
 java.lang.String toString()
           
 Value value(QueryContext ctx)
          Evaluates the expression and returns the resulting value.
 
Methods inherited from class org.basex.query.expr.Single
accept, count, exprSize, has, inline, removable
 
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, optPre, preEval, size, test, type
 
Methods inherited from class org.basex.query.expr.Expr
addText, compEbv, copy, hasFreeVars, indexAccessible, indexEquivalent, inlineAll, isEmpty, isFunction, isItem, isVacuous, isValue, iterable, optimize, sameAs, uses, visitAll
 
Methods inherited from class org.basex.data.ExprInfo
addPlan, addPlan, description, info, planAttr, planElem
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

Extension

public Extension(InputInfo ii,
                 Pragma[] prag,
                 Expr e)
Constructor.

Parameters:
ii - input info
prag - pragmas
e - enclosed expression
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.

Overrides:
checkUp in class Single
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.

Overrides:
compile in class Single
Parameters:
ctx - query context
scp - variable scope
Returns:
optimized expression
Throws:
QueryException - query exception

iter

public ValueIter iter(QueryContext ctx)
               throws QueryException
Description copied from class: Expr
Evaluates the expression and returns an iterator on the resulting items. If this method is not overwritten, Expr.item(org.basex.query.QueryContext, org.basex.util.InputInfo) must be implemented by an expression, as it may be called by this method.

Overrides:
iter in class ParseExpr
Parameters:
ctx - query context
Returns:
resulting item
Throws:
QueryException - query exception

value

public Value value(QueryContext ctx)
            throws QueryException
Description copied from class: Expr
Evaluates the expression and returns the resulting value.

Overrides:
value in class ParseExpr
Parameters:
ctx - query context
Returns:
iterator
Throws:
QueryException - query exception

copy

public Expr copy(QueryContext ctx,
                 VarScope scp,
                 IntObjMap<Var> vs)
Description copied from class: Expr
Copies an expression. Will be useful for inlining functions, or for copying static queries.

Specified by:
copy in class Expr
Parameters:
ctx - query context
scp - variable scope for creating new variables
vs - mapping from old variable IDs to new variable copies
Returns:
copied expression

plan

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

Overrides:
plan in class Single
Parameters:
plan - root element

toString

public java.lang.String toString()
Specified by:
toString in class ExprInfo

markTailCalls

public Expr markTailCalls()
Description copied from class: Expr
Finds and marks tail calls, enabling TCO.

Overrides:
markTailCalls in class Expr
Returns:
the expression, with tail calls marked