XPath notation

XPath notation used in this specification

XPath is a way to refer to parts of an XML document, for example, a JDF ticket. A simple subset of the XPath language [XPath] is used in the description of an element, attribute or value to identify other elements, attributes and/or values.

The simple subset of XPath used is:

• Element subelement hierarchy is indicated by a slash: element/element

  For example: /JDF/ResourcePool/DigitalPrintingParams/Disjointing/InsertSheet

• Element attribute hierarchy is indicated by a slash and an at (@) symbol: element/@attribute

  For example: /JDF/ResourcePool/DigitalPrintingParams/Disjointing/InsertSheet/@SheetType

• Paths beginning with a single slash: "/" indicate root elements. /JDF indicates the root JDF node

  For example: /JDF/ResourcePool/DigitalPrintingParams/Disjointing/InsertSheet

• Paths beginning with a double slash "//" indicate elements with a parent.

  For example: //DigitalPrintingParams/Disjointing/InsertSheet. This XPath means that DigitalPrintingParams must be part of an other element. The DigitalPrintingParams is part of the ResourcePool element and the ResourcePool element is part of the JDF node. So, the full XPath is:

  /JDF/ResourcePool/DigitalPrintingParams/Disjointing/InsertSheet

• Predicates are always embedded in square brackets. Predicates are used to find a specific node or a node that contains a specific value.

  This document can contain the following types of predicates:

  • E[@A = V]

    The XPath specifies an element E whose attribute A has the value V.

    For example: InsertSheet[@SheetType="SeparatorSheet"]. In XML this becomes: <InsertSheet SheetType="SeparatorSheet"/>

  • E[contains(@A = V)]

    The XPath specifies an element E that contains at least attribute A. Attribute A has the value V.

    For example: /JDF[contains(@Types="Trimming")]. At least Types="Trimming" must be part of the JDF node, so in XML this can be: <JDF Type="Combined" Types="Trimming LayoutPreparation Imposition Interpreting Rendering DigitalPrinting HoleMaking Folding Stitching">

  • E[@A]

    The XPath specifies an element E in which attribute A is present.

    For example: /JDF/Comment[@Name="Instruction"]. In XML this becomes:

    <JDF>

    <Comment Name="Instruction">some text</Comment>

    </JDF>

Example 1

XPath: /JDF/ResourcePool/Media/GeneralID[@IDUsage="oce:Orientation"]/@IDValue

This XPath refers to the following part of an XML document:

<JDF>
    <ResourcePool>
        <Media>
            <GeneralID IDUsage="oce:Orientation" IDValue="LongEdgeFeed" />
        </Media>
    </ResourcePool>
</JDF>

Example 2

XPath: /JDF[contains(@Types="Trimming")]/ResourcePool/TrimmingParams/GeneralID[@IDUsage="oce:CutWidth"]/@IDValue

This XPath refers to the following part of an XML document:

<JDF Type="Combined" Types="Trimming LayoutPreparation Imposition Interpreting Rendering DigitalPrinting HoleMaking Folding Stitching">
    <ResourcePool>
        <TrimmingParams>
            <GeneralID IDUsage="oce:CutWidth" IDValue="<double>" />
        </TrimmingParams>
    </ResourcePool>
</JDF>

Example 3

/JDF/ResourcePool/Contact[contains(@ContactTypes="Owner") and @ID="<text>"]/@oce:UserID/oce:ComChannel[@ChannelType="ComputerName"]/@Locator

This XPath refers to the following part of an XML document:

<JDF>
    <ResourcePool>
        <Contact ID="<text>" ContactTypes="Owner" oce:UserID="<text>">
            <oce:ComChannel ChannelType="ComputerName" Locator="<hostname>" />
        </Contact>
    </ResourcePool>
</JDF>

Archive with examples for download

NOTE

If you want to use this snippet, download the whole collection of examples in this TRM from this link:

https://supportfiles.cpp.canon/trm/Examples-TRM-Mk8.1.1.zip