Xbase++

XML Tree Traversal Order for Search* Methods

See more XML Examples

The Chilkat XML API provides a number of Search* methods for locating XML nodes based on criteria. These methods traverse an XML document in a breadth-first order. (See Breadth-First Search).

The XML document used in this example has the following tree structure:

The nodes are traversed in the order: A, B, C, D, E, F, G, H, I, J, K.

The input XML, available at http://www.chilkatsoft.com/data/searchOrder.xml, is this:

<a>crocodileA
    <b>crocodileB
        <d>crocodileD</d>
        <e>crocodileE
            <h>crocodileH</h>
            <i>crocodileI</i>
        </e>
    </b>
    <c>crocodileC
        <f>crocodileF</f>
        <g>crocodileG
            <j>crocodileJ</j>
            <k>crocodileK</k>
        </g>
    </c>
</a>

Xbase++

LOCAL nSuccess
LOCAL oXml
LOCAL oXBeginAfter
LOCAL oXFound

nSuccess := 0

oXml := CreateObject("Chilkat.Xml")

//  The sample input XML is available at http://www.chilkatsoft.com/data/searchOrder.xml
nSuccess := oXml:LoadXmlFile("searchOrder.xml")
IF (nSuccess != 1)
    ? oXml:LastErrorText
    oXml:destroy()
    RETURN
ENDIF

//  IMPORTANT:  The following loop for iterating over all 
//  matching nodes performs reasonably well for small to 
//  mid-size XML documents or sub-trees.  Performance
//  can be poor when the sub-tree contains many thousands
//  of nodes (or more).

//  NOTE:  The search is always rooted at the calling node.
//  In this example, it happens to also be the root node of the entire
//  XML document.  Searches can be performed on sub-trees
//  within the document by calling the Search* method from
//  the root node of a sub-tree.

//  Demonstrate the breadth-first traversal:
oXBeginAfter := oXml:GetSelf()
oXFound := oXml:SearchAllForContent(oXBeginAfter, "*croc*")
DO WHILE (oXml:LastMethodSuccess == 1)

    ? oXFound:Tag

    oXBeginAfter:destroy()
    oXBeginAfter := oXFound
    oXFound := oXml:SearchAllForContent(oXBeginAfter, "*croc*")
ENDDO

oXBeginAfter:destroy()

oXml:destroy()