(DataFlex) XML Tree Traversal Order for Search* Methods

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>

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-win32.pkg

Procedure Test
    Handle hoXml
    Variant vXBeginAfter
    Handle hoXBeginAfter
    Variant vXFound
    Handle hoXFound
    Boolean iSuccess
    String sTemp1

    Get Create (RefClass(cComChilkatXml)) To hoXml
    If (Not(IsComObjectCreated(hoXml))) Begin
        Send CreateComObject of hoXml
    End

    // The sample input XML is available at http://www.chilkatsoft.com/data/searchOrder.xml
    Get ComLoadXmlFile Of hoXml "searchOrder.xml" To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoXml To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // 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:
    Get ComGetSelf Of hoXml To vXBeginAfter
    If (IsComObject(vXBeginAfter)) Begin
        Get Create (RefClass(cComChilkatXml)) To hoXBeginAfter
        Set pvComObject Of hoXBeginAfter To vXBeginAfter
    End
    Get ComSearchAllForContent Of hoXml vXBeginAfter "*croc*" To vXFound
    If (IsComObject(vXFound)) Begin
        Get Create (RefClass(cComChilkatXml)) To hoXFound
        Set pvComObject Of hoXFound To vXFound
    End
    While ((ComLastMethodSuccess(hoXml)) = True)

        Get ComTag Of hoXFound To sTemp1
        Showln sTemp1

        Send Destroy of hoXBeginAfter
        Move hoXFound To hoXBeginAfter
        Get ComSearchAllForContent Of hoXml vXBeginAfter "*croc*" To vXFound
        If (IsComObject(vXFound)) Begin
            Get Create (RefClass(cComChilkatXml)) To hoXFound
            Set pvComObject Of hoXFound To vXFound
        End
    Loop

    Send Destroy of hoXBeginAfter


End_Procedure