ch.ethz.mxquery.iterators
Class OrderByIterator

java.lang.Object
  ch.ethz.mxquery.model.Iterator
      ch.ethz.mxquery.model.CurrentBasedIterator
          ch.ethz.mxquery.iterators.OrderByIterator

All Implemented Interfaces:

XDMIterator, Traversable

public class OrderByIterator
extends CurrentBasedIterator

Represents an order by expression of a flwor expression.
TODO Collation & stable

Nested Class Summary

class

OrderByIterator.OrderElComp

Field Summary

Fields inherited from interface ch.ethz.mxquery.model.XDMIterator

EXPR_CATEGORY_SEQUENTIAL, EXPR_CATEGORY_SIMPLE, EXPR_CATEGORY_UPDATING, EXPR_CATEGORY_VACUOUS, EXPR_PARAM_CHEAPEVAL, EXPR_PARAM_VARIABLE, EXPR_PARAM_WINDOW, EXPR_PARAM_XDMGEN

Constructor Summary

OrderByIterator(Context ctx, XDMIterator[] orderIterators, OrderOptions[] orderOptions, boolean stable, QueryLocation location)

Method Summary

Token[]	getCurrentKey() Computes the key of the current context => Computes for every order by expression a Token that contains the key value.
Token	next() Produces the next XDM token This method typically implements the base functionality of an Iterator and computes the value of the next token.
void	setup(ch.ethz.mxquery.iterators.OrderByIterator.OrderElement[] orderElements) Sorts the passed order elements.
KXmlSerializer	traverseIteratorTree(KXmlSerializer serializer)

Methods inherited from class ch.ethz.mxquery.model.Iterator

addPredicates, close, copy, copyInts, copyIterators, copyQNames, copyStrings, copyTypeInfos, getAllSubIters, getAllSubItersRecursive, getContext, getExpressionCategoryType, getLoc, getPendingUpdateList, getPredicates, getStaticType, getSubIters, hasPredicates, isConstModePreserve, isExprParameter, isOpen, isResettable, removePredicates, reset, setConstModePreserve, setContext, setLoc, setOrderByExpr, setParam, setResettable, setReturnExpr, setSubIters, setSubIters, setSubIters, setWhereExpr, traverse

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

OrderByIterator

public OrderByIterator(Context ctx,
                       XDMIterator[] orderIterators,
                       OrderOptions[] orderOptions,
                       boolean stable,
                       QueryLocation location)
                throws MXQueryException

Throws:

MXQueryException

Method Detail

getCurrentKey

public Token[] getCurrentKey()
                      throws MXQueryException

Computes the key of the current context => Computes for every order by expression a Token that contains the key value.

Returns:

the sequence of order keys

Throws:

MXQueryException

setup

public void setup(ch.ethz.mxquery.iterators.OrderByIterator.OrderElement[] orderElements)
           throws MXQueryException

Sorts the passed order elements.

Parameters:

orderElements -

Throws:

MXQueryException

next

public Token next()
           throws MXQueryException

Description copied from interface: XDMIterator

Produces the next XDM token This method typically implements the base functionality of an Iterator and computes the value of the next token.

Returns:

The XDM token representing the next fragment of the XDM instance

Throws:

MXQueryException

traverseIteratorTree

public KXmlSerializer traverseIteratorTree(KXmlSerializer serializer)
                                    throws java.lang.Exception

Specified by:

traverseIteratorTree in interface XDMIterator

Overrides:

traverseIteratorTree in class Iterator

Throws:

java.lang.Exception