<HTML>
<HEAD>
<TITLE>XML to DOM Converter: Listing 3</TITLE>
<APPLET CODE=com.ms.xml.dso.XMLDSO.class WIDTH=100% HEIGHT=30
ID=xmldso MAYSCRIPT=true>
<PARAM NAME="url" VALUE="someXMLDocument.xml">
</APPLET>
</HEAD>
<BODY>
<SCRIPT>
_root = xmldso.getDocument().root
results = window.document;
// Simple stack ADT
function stack()
{
this.depth = 0;
this.data = new Array();
this.push = push;
this.pop = pop;
this.popTop = popTop;
this.length = length;
this.exists = exists;
return this;
}
// Add an item
function push( item )
{
this.data[ this.depth ++ ] = item;
}
// Remove last item
function pop()
{
if ( this.depth )
{
this.depth --;
return this.data[ this.depth ];
}
return null;
}
// Remove item at head of stack
function popTop()
{
if ( this.depth )
{
// Pop the top item
_j = this.data[ 0 ];
this.depth --;
// Shuffle the stack up a place
for ( _i = 0; _i < this.depth; _i ++ )
{
this.data[ _i ] = this.data[ _i + 1 ]
}
return _j;
}
return null;
}
// Return the size of the stack
function length()
{
return this.depth;
}
// Does the stack hold the specified item?
function exists( obj )
{
for ( _i = 0; _i < this.depth; _i ++ )
{
if ( this.data[ _i ] == obj )
{
return true;
}
}
return false;
}
function xmltodom()
{
// Cache the XML root, since retrieving it more than once via
// getDocument() causes an error
var root = _root
// Holds XML node objects
var x = new stack();
// Holds incremental document description tags
var y = new stack();
// Holds unique paths of descent to XML leaf nodes
var d = new stack();
x.push( root );
y.push( "document." + root.tagname + "." );
while ( x.length() != 0 )
{
// Pop top items, so that DOM tree is same way up as XML
// tree; it would be easier simply to push them in reverse
// order, but xmldso.class seems to have problems navigating
// a node's child-list backwards rather than forwards
var xmlTag = x.popTop();
var docTag = y.popTop();
// If the XML node is a leaf, assign its DOM equivalent its
// textual value; otherwise create a new DOM object
var docString = docTag.substring( 0, docTag.length - 1 ) + " = ";
if ( xmlTag.children.length != 0 )
{
docString += "new " + xmlTag.tagname + "();<br>";
}
else
{
docString += "'" + xmlTag.text + "';<br>";
}
results.writeln( docString );
// Check that our XML tag is of type "ELEMENT"
if ( xmlTag.type == 0 )
{
if ( xmlTag.children.length == 0 )
{
// Generate the complete path to the element
var iter = xmlTag;
var t = new stack();
while ( iter.parent != null )
{
t.push( iter.tagname );
iter = iter.parent;
}
// Reverse the path
var path = "";
while ( t.length() )
{
path += t.pop() + ".";
}
// Check whether this object path has already
// been generated
if ( !d.exists( path ) )
{
d.push( path );
}
}
}
// Stack children of this XML node
if ( xmlTag.children )
{
// Might seem logical to cache xmlTag.children, but if
// you do XMLDSO won't work properly
for ( i = 0; i < xmlTag.children.length; i ++ )
{
x.push( xmlTag.children.item( i ) );
// How many instances of a given child node at
// this level?
var numInstances = 0;
for ( j = 0; j < xmlTag.children.length; j ++ )
{
if ( xmlTag.children.item( i )
.tagName == xmlTag.children.item( j ).tagName )
{
numInstances ++;
}
}
// Get instance index for current node
var thisInstance = -1;
for ( j = 0; j < i + 1; j ++ )
{
if ( xmlTag.children.item( j )
.tagname == xmlTag.children.item( i ).tagname )
{
thisInstance ++;
}
}
if ( numInstances > 1 )
{
y.push( docTag + xmlTag.children.item( i )
.tagname + "[ " + thisInstance + " ]." );
}
else
{
y.push( docTag + xmlTag.children.item( i )
.tagname + "." );
}
}
}
}
// Now generate the ADT function prototypes for this XML document
results.writeln( "<br>" );
// Store the tree depth we have parsed
var objDepth = 0;
while ( true )
{
// Create an array of stacks to hold the collections
// of sub-elements
var newTerms = new Array();
newTerms[ newTerms.length ] = new stack();
// This will hold the immediate parent of each
// "newTerms" stack
var baseTerms = new Array();
for ( i = 0; i < d.length(); i ++ )
{
var str = d.data[ i ];
var testDepth = 0;
var lastDot = 0;
for ( j = 0; j < str.length; j ++ )
{
if ( testDepth == objDepth )
{
break;
}
if ( str.charAt( j ) == "." )
{
testDepth ++;
if ( testDepth == objDepth - 1 )
{
lastDot = j;
}
}
}
if ( j < str.length )
{
var listNum = 0;
var baseObject = str.substring( lastDot ? lastDot +
1 : 0, j - 1 );
// If this parent has already been assigned,
// locate it; otherwise assign another one and
// add it to the array
var fFound = false;
for ( k = 0; k < baseTerms.length; k ++ )
{
if ( baseTerms[ k ] == baseObject )
{
fFound = true;
break;
}
}
if ( !fFound )
{
listNum = baseTerms.length;
newTerms[ listNum ] = new stack();
baseTerms[ baseTerms.length ] = baseObject;
}
else
{
listNum = k;
}
str = str.substring( j, str.indexOf( ".", j + 1 ) );
// If the sub-element is unique, add it to the
// appropriate sub-element collection
if ( !newTerms[ listNum ].exists( str ) )
{
newTerms[ listNum ].push( str );
}
}
}
// Parse the two stacks, creating a Javascript object named
// after each parent, and containing the collection
// of sub-elements dependent upon that parent
if ( objDepth != 0 )
{
var fItems = false;
for ( l = 0; l < baseTerms.length; l ++ )
{
if ( baseTerms[ l ].length )
{
results.writeln( "function " + baseTerms[ l ]
+ "()<br>" );
results.writeln( "{<br>" );
while ( newTerms[ l ].length() )
{
fItems = true;
results.writeln( "
this." + newTerms[ l ].pop()
+ " = new Array();<br>" );
}
results.writeln( "
return this;<br>" );
results.writeln( "}<br><br>" );
}
}
// If there were no items, we have finished traversing
if ( !fItems )
{
break;
}
}
objDepth ++;
}
}
// Convert the loaded document
xmltodom()
</SCRIPT>
</BODY>
</HTML>
Script Junkie | An XML Document to JavaScript Object Converter (Web Techniques,
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