com.ibm.tspaces.xtuples
Class TupleTree

java.lang.Object
  |
  +--com.ibm.tspaces.xtuples.TupleTree

public class TupleTree

extends java.lang.Object

implements java.io.Serializable

TupleTree is the class that represents the entirety of the XML document that has been converted to the TupleTree. Every single tuple in the tuple tree has a pointer reference to this object, which represents the entire tree structure. Every Tuple includes as one of its fields a XTuple object which embeds the XML related data and the child and parent Tuple references.

This class is used to create and initialize the Tuple Tree.
***MISSING FUNCTIONALITY*** Here's a Key Divergence from the XQL support that's possibly planned for the future. I'm making a decision to not support mixed content (i.e. a single element which has both simple text children and element children mixed together. That's usually used for presentation, a la conversion from HTML to XML or vice versa.) To make version 1 easier, I will assume that DOM nodes/tags which contain text contain no children, and that all the text is together in one string. This string gets put into a known field of the Tuple, and will be very useful in supporting XQL path expression queries, by using TSpaces to find those tuples easily using structural/template matches.
***KEY ASSUMPTION*** We assume that by the time this code is run from the TSDB.java code, the clientID is established, as is the current transaction.

Author:

Ben Y. Zhao

See Also:

XTuple, Field, XMLField, TSDB, XTupleException, Serialized Form

Constructor Summary

TupleTree(java.lang.String xmlString, com.ibm.tspaces.server.TSDB dbPtr, java.lang.String cID, long timestamp, long expire, TupleID origTID)
TupleTree (String, TSDB, String, long, long, TupleID) ** Constructor

Method Summary

static java.util.Vector	getChildren(org.w3c.dom.Element e) Methods that takes an XML4J/DOM element and returns its children, ignoring whitespaces between tags
java.lang.String	getDTDName() This method returns as a string the DTD name that was referenced in the XML document version of the Tuple Tree.
XMLTuple	getRoot() This is the standard mechanism by which a client with a reference on a Tuple Tree manages to start traversing the tree.
static int	numChildren(org.w3c.dom.Element e) Method to take an XML4J DOM element and count its number of children Whitespaces here are not ignored.
void	setRoot(XMLTuple newRoot) Method for authorized users to "set" the root tuple of the Tuple Tree I'm still a little unclear on what the qualifier should be, maybe protected?
java.lang.String	toString() Prints out the value of the tuple and then dumps the contents of the XTuple object

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

TupleTree

public TupleTree(java.lang.String xmlString,
                 com.ibm.tspaces.server.TSDB dbPtr,
                 java.lang.String cID,
                 long timestamp,
                 long expire,
                 TupleID origTID)
          throws TupleSpaceServerException

TupleTree (String, TSDB, String, long, long, TupleID) ** Constructor

Parameters:

xmlString - Self explanatory

dbPtr - The pointer to the current TSDB

cID - The current ClientID

timestamp - The timestamp for the entire tupletree

expire - The expiration time for the whole tupletree

origTID - The tupleID ref to the original XMLField tuple

Method Detail

getRoot

public XMLTuple getRoot()

This is the standard mechanism by which a client with a reference on a Tuple Tree manages to start traversing the tree. It returns the root Tuple of the tuple tree

setRoot

public void setRoot(XMLTuple newRoot)
             throws XTupleException

Method for authorized users to "set" the root tuple of the Tuple Tree I'm still a little unclear on what the qualifier should be, maybe protected?

Returns:

boolean: success or failure

getDTDName

public java.lang.String getDTDName()

This method returns as a string the DTD name that was referenced in the XML document version of the Tuple Tree. We can think about using this functionality to "translate" DTDs over to validating tuples maybe.

Returns:

String representation of the DTD name

numChildren

public static int numChildren(org.w3c.dom.Element e)

Method to take an XML4J DOM element and count its number of children Whitespaces here are not ignored. For that, do getChildren().size()

Parameters:

e - The DOM element in question

Returns:

integer that represents the number of children it has

getChildren

public static java.util.Vector getChildren(org.w3c.dom.Element e)

Methods that takes an XML4J/DOM element and returns its children, ignoring whitespaces between tags

Parameters:

e - The DOM element that we find nonwhitespace children for

Returns:

Vector containing the child DOM elements

toString

public java.lang.String toString()

Prints out the value of the tuple and then dumps the contents of the XTuple object

Overrides:

toString in class java.lang.Object