ch.ethz.mxquery.update.store.llImpl
Class LLStoreIterator

java.lang.Object
  ch.ethz.mxquery.model.Iterator
      ch.ethz.mxquery.model.Window
          ch.ethz.mxquery.update.store.llImpl.LLStoreIterator

All Implemented Interfaces:

IndexIterator, XDMIterator, Traversable

public class LLStoreIterator
extends Window

Iterator hides the XML Store functionality and behaves like the Iterator from the MXQuery.

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

LLStoreIterator(Identifier startID, LLStore store)
Constructor.

Method Summary

void	destroyWindow() Destroys the connection to the window buffer and gives the used item free for garbage collection
boolean	equals(java.lang.Object other)
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()
java.lang.String	getSourceURI()
int	getStartNode() Returns the first node id of the window
Source	getStore()
int	getWindowId() Every window has a unique id given by the buffer the window is working on.
int	hashCode()
boolean	hasItem(int position) Checks if the given position is availabe
boolean	hasNextItem() Returns true if there is an item at all or if the actual item as a sibling.
boolean	isEmpty()
boolean	isWindowInUse() If a window is not in use it is a schema for other windows.
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.
void	setContext(Context context, boolean recursive) Assigns a context for this iterator (and possibly for its subIterators), replacing the existing context
void	setWindowInUse(boolean windowInUse) Specifies if a window can be used again.

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, 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

LLStoreIterator

public LLStoreIterator(Identifier startID,
                       LLStore store)

Constructor.

Parameters:

startID - the id of the node on which the iteration should start

store - store on which to generate the

Method Detail

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

getStartNode

public int getStartNode()
                 throws MXQueryException

Description copied from class: Window

Returns the first node id of the window

Specified by:

getStartNode in class Window

Returns:

returns the first node id of this window

Throws:

MXQueryException

isEmpty

public boolean isEmpty()
                throws MXQueryException

Throws:

MXQueryException

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

getNewWindow

public Window getNewWindow(int startPosition,
                           int endPosition)
                    throws MXQueryException

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

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

Returns true if there is an item at all or if the actual item as a sibling.

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

setContext

public void setContext(Context context,
                       boolean recursive)

Description copied from interface: XDMIterator

Assigns a context for this iterator (and possibly for its subIterators), replacing the existing context

Specified by:

setContext in interface XDMIterator

Overrides:

setContext in class Iterator

Parameters:

context - the context to assign

recursive - true perform the assignment also subiteratos, false only replace on the current iterator

destroyWindow

public void destroyWindow()

Description copied from class: Window

Destroys the connection to the window buffer and gives the used item free for garbage collection

Specified by:

destroyWindow in class Window

equals

public boolean equals(java.lang.Object other)

Specified by:

equals in class Window

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

getWindowId

public int getWindowId()

Description copied from class: Window

Every window has a unique id given by the buffer the window is working on.

Specified by:

getWindowId in class Window

Returns:

the identifier of this window

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

isWindowInUse

public boolean isWindowInUse()

Description copied from class: Window

If a window is not in use it is a schema for other windows. E.g. a LET/FOR/FORSEQ binds a window to a variable the window is not in use yet. But in the moment the first variable reference is using the window the window is in used

Specified by:

isWindowInUse in class Window

Returns:

true if the window is use, false otherwise

setWindowInUse

public void setWindowInUse(boolean windowInUse)

Description copied from class: Window

Specifies if a window can be used again. This method is normally only used by the variable iterator. Be carefully with it, as it is mainly responsible to allow proper garbage collection.

Specified by:

setWindowInUse in class Window

getSourceURI

public java.lang.String getSourceURI()

getPosition

public int getPosition()

Specified by:

getPosition in class Window

getStore

public Source getStore()

Specified by:

getStore in class Window