org.basex.query.expr
Class Instance

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.Instance

public final class Instance
extends Single

Instance test.

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
 
Fields inherited from class org.basex.query.expr.Single
expr
 
Fields inherited from class org.basex.query.expr.ParseExpr
info, size, type
 
Constructor Summary
Instance(InputInfo ii, Expr e, SeqType s)
          Constructor.
 
Method Summary
 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.
 Bln item(QueryContext ctx, InputInfo ii)
          Evaluates the expression and returns the resulting item or a null reference, if the expression yields an empty sequence.
 void plan(FElem plan)
          Creates an expression tree.
 java.lang.String toString()
           
 
Methods inherited from class org.basex.query.expr.Single
accept, checkUp, 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, iter, optPre, preEval, size, test, type, value
 
Methods inherited from class org.basex.query.expr.Expr
addText, compEbv, copy, hasFreeVars, indexAccessible, indexEquivalent, 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
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

Instance

public Instance(InputInfo ii,
                Expr e,
                SeqType s)
Constructor.

Parameters:
ii - input info
e - expression
s - sequence type
Method Detail

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

item

public Bln item(QueryContext ctx,
                InputInfo ii)
         throws QueryException
Description copied from class: Expr
Evaluates the expression and returns the resulting item or a null reference, if the expression yields an empty sequence. If this method is not overwritten, Expr.iter(org.basex.query.QueryContext) must be implemented by an expression, as it may be called by this method.

Overrides:
item in class ParseExpr
Parameters:
ctx - query context
ii - input info
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