ch.ethz.mxquery.bindings
Class WindowEmptySequenceIterator

java.lang.Object
  ch.ethz.mxquery.model.Iterator
      ch.ethz.mxquery.model.Window
          ch.ethz.mxquery.bindings.WindowIterator
              ch.ethz.mxquery.bindings.WindowEmptySequenceIterator

All Implemented Interfaces:

IndexIterator, XDMIterator, Traversable

public final class WindowEmptySequenceIterator
extends WindowIterator

Dummy iterator to represent an empty window

Field Summary

Fields inherited from class ch.ethz.mxquery.model.Window

END_OF_STREAM_NODE, END_OF_STREAM_POSITION

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

WindowEmptySequenceIterator(WindowBuffer mat, int windowId)

Method Summary

XDMIterator	getItem(int position) Returns the item on the given Position.
Window	getNewItemWindow(IntegerList values) Returns a new iterator consisting of the given items in the integer list.
Window	getNewWindow(int startPosition, int endPosition) Returns a new iterator for a given start and end position.
int	getPosition()
int	getStartNode() Returns the first node id of the window
boolean	hasItem(int position) Checks if the given position is availabe
boolean	hasNextItem() Checks if a nextItem exists
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.
XDMIterator	nextItem() Returns the next item.

Methods inherited from class ch.ethz.mxquery.bindings.WindowIterator

destroyWindow, equals, getStore, getWindowId, hashCode, isWindowInUse, setContext, setWindowInUse

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

getEndPosition, getNewEarlyParallelWindowInterface, getNewEarlyWindowInterface, getNextWindowStartPosition, getUnderlyingWindow, increasePosition, isExprParameter, isWindow, jumpToNextAttribute, setPosition

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, isOpen, isResettable, removePredicates, reset, setConstModePreserve, setContext, setLoc, setOrderByExpr, setParam, setResettable, setReturnExpr, setSubIters, setSubIters, setSubIters, setWhereExpr, traverse, traverseIteratorTree

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

WindowEmptySequenceIterator

public WindowEmptySequenceIterator(WindowBuffer mat,
                                   int windowId)

Method Detail

getItem

public XDMIterator getItem(int position)
                    throws MXQueryException

Description copied from interface: IndexIterator

Returns the item on the given Position. If the item is not evailabe, an empty sequence item is returned

Parameters:

position - Position in the sequence (starting with 1)

Returns:

Item or empty sequence iterator

Throws:

MXQueryException

getNewItemWindow

public Window getNewItemWindow(IntegerList values)

Description copied from class: Window

Returns a new iterator consisting of the given items in the integer list. If a position is outside the underlying sequence, the position is skipped.

Specified by:

getNewItemWindow in class Window

Parameters:

values - Each value in the integer list has to be a position

Returns:

a new Window for the given list of positions

getNewWindow

public Window getNewWindow(int startPosition,
                           int endPosition)

Description copied from class: Window

Returns a new iterator for a given start and end position. If the end is outside the underlying sequence the iterator throws no error but only returns items until the sequence ends

Specified by:

getNewWindow in class Window

Returns:

a new window for the given start and end positions

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

hasItem

public boolean hasItem(int position)
                throws MXQueryException

Description copied from interface: IndexIterator

Checks if the given position is availabe

Parameters:

position - Position in the sequence (starting with 1)

Returns:

True if the next item is not end_sequence otherwise false

Throws:

MXQueryException

hasNextItem

public boolean hasNextItem()
                    throws MXQueryException

Description copied from interface: IndexIterator

Checks if a nextItem exists

Returns:

True if the next item is not end_sequence otherwise false

Throws:

MXQueryException

nextItem

public XDMIterator nextItem()
                     throws MXQueryException

Description copied from interface: IndexIterator

Returns the next item. If the item is not evailabe, an empty sequence item is returned

Returns:

Item or empty sequence iterator

Throws:

MXQueryException

getStartNode

public int getStartNode()

Description copied from class: Window

Returns the first node id of the window

Specified by:

getStartNode in class WindowIterator

Returns:

returns the first node id of this window

getPosition

public int getPosition()

Specified by:

getPosition in class Window