Swift

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>

Swift

func chilkatTest() {
    var success: Bool = false

    let xml = CkoXml()!
    var xBeginAfter: CkoXml?
    var xFound: CkoXml?

    // The sample input XML is available at http://www.chilkatsoft.com/data/searchOrder.xml
    success = xml.loadFile(path: "searchOrder.xml")
    if success != true {
        print("\(xml.lastErrorText!)")
        return
    }

    // 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:
    xBeginAfter = xml.getSelf()
    xFound = xml.searchAll(forContent: xBeginAfter, contentPattern: "*croc*")
    while (xml.lastMethodSuccess == true) {

        print("\(xFound!.tag!)")

        xBeginAfter = nil
        xBeginAfter = xFound
        xFound = xml.searchAll(forContent: xBeginAfter, contentPattern: "*croc*")
    }

    xBeginAfter = nil

}