org.basex.query.expr
Class Arr

java.lang.Object
  extended by org.basex.query.ExprInfo
      extended by org.basex.query.expr.Expr
          extended by org.basex.query.expr.Arr
Direct Known Subclasses:
And, CFrag, Clc, CmpG, CmpN, CmpV, Except, Fun, FunCall, FunJava, If, InterSect, List, Or, Range, Transform, Union, Update

public abstract class Arr
extends Expr

Abstract array expression.

Author:
Workgroup DBIS, University of Konstanz 2005-10, ISC License, Christian Gruen

Nested Class Summary
 
Nested classes/interfaces inherited from class org.basex.query.expr.Expr
Expr.Use
 
Field Summary
 Expr[] expr
          Expression list.
 
Method Summary
 Expr comp(QueryContext ctx)
          Optimizes and compiles the expression.
 boolean duplicates(QueryContext ctx)
          Returns true if the expression might yield duplicates and unsorted results.
 Expr indexEquivalent(IndexContext ic)
          Returns an equivalent expression which accesses an index structure.
 void plan(Serializer ser)
          Recursively sends the abstract syntax of this expression to the specified serializer.
 boolean removable(Var v, QueryContext ctx)
          Checks if the specified variable is removable.
 Expr remove(Var v)
          Removes the specified variable in a sub expression.
 boolean uses(Expr.Use u, QueryContext ctx)
          Indicates if an expression uses the specified type.
 
Methods inherited from class org.basex.query.expr.Expr
addText, atomic, checkCtx, checkDbl, checkItr, e, ebv, i, indexAccessible, iter, returned, sameAs, size, test, v
 
Methods inherited from class org.basex.query.ExprInfo
color, info, name, toString
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

expr

public Expr[] expr
Expression list.

Method Detail

comp

public Expr comp(QueryContext ctx)
          throws QueryException
Description copied from class: Expr
Optimizes and compiles the expression.

Specified by:
comp in class Expr
Parameters:
ctx - query context
Returns:
optimized Expression
Throws:
QueryException - query exception

uses

public boolean uses(Expr.Use u,
                    QueryContext ctx)
Description copied from class: Expr
Indicates if an expression uses the specified type. Called by the compiler to perform certain optimizations. true is returned by default and thus assumed as "worst-case".

Specified by:
uses in class Expr
Parameters:
u - use type to be checked
ctx - query context
Returns:
result of check

removable

public boolean removable(Var v,
                         QueryContext ctx)
Description copied from class: Expr
Checks if the specified variable is removable.

Overrides:
removable in class Expr
Parameters:
v - variable to be removed
ctx - query context
Returns:
result of check

remove

public Expr remove(Var v)
Description copied from class: Expr
Removes the specified variable in a sub expression.

Overrides:
remove in class Expr
Parameters:
v - variable to be removed
Returns:
expression with removed variable

indexEquivalent

public Expr indexEquivalent(IndexContext ic)
                     throws QueryException
Description copied from class: Expr
Returns an equivalent expression which accesses an index structure. Must be called if Expr.indexAccessible(org.basex.query.IndexContext) is implemented for an expression.

Overrides:
indexEquivalent in class Expr
Parameters:
ic - index context
Returns:
Equivalent index-expression or null
Throws:
QueryException - query exception

duplicates

public boolean duplicates(QueryContext ctx)
Description copied from class: Expr
Returns true if the expression might yield duplicates and unsorted results.

Overrides:
duplicates in class Expr
Parameters:
ctx - query context
Returns:
result of check

plan

public void plan(Serializer ser)
          throws IOException
Description copied from class: ExprInfo
Recursively sends the abstract syntax of this expression to the specified serializer.

Specified by:
plan in class ExprInfo
Parameters:
ser - serializer
Throws:
IOException - I/O exception