XML Templates Examples

Input Data used for the examples

1. currentView
2. anotherView

Rules examples

1. Rename an element
2. Ignore a subtree
3. Ignore an element (but keep its descendant nodes)
4. Ignore a subtree, with a condition of self node
5. Ignore a subtree, with a condition of child nodes
6. Create a new element
7. Join two data views
8. Join two data views (with hash table)
9. Join two data views (with indexed cache)
10. Sort elements
11. Group elements

Input Data used for the examples

currentView

        <connector type="XMLConnector">
            <parameter name="content"><[CDATA[
<root>
    <child key="1">
        <english>one</english>
        <english>ten</english>
        <english>hundred</english>
    </child>
    <child key="2">
        <english>two</english>
        <english>twenty</english>
    </child>
</root>]]></parameter>
        </connector>

---

anotherView

        <connector type="XMLConnector">
            <parameter name="content"><[CDATA[
<anotherRoot>
    <anotherChild anotherKey="1">
        <french>un</french>
        <french>dix</french>
        <french>cent</french>
    </anotherChild>
    <anotherChild anotherKey="2">
        <french>deux</french>
        <french>vingt</french>
    </anotherChild>
</anotherRoot>]]></parameter>
        </connector>

Rules examples

Rename an element

Rename element /root/child to /root/newChild.

            <element in="root">
                <element in="child" out="newChild"/>
            </element>

Output

<root>
    <newChild key="1">
        <english>one</english>
        <english>ten</english>
        <english>hundred</english>
    </newChild>
    <newChild key="2">
        <english>two</english>
        <english>twenty</english>
    </newChild>
</root>

---

Ignore a subtree

Ignore node /root/child and all its descendant nodes.

            <element in="root">
                <element-ignore in="child"/>
            </element>

Output

<root>
</root>

---

Ignore an element (but keep its descendant nodes)

Ignore node /root/child, but keep its descendant nodes.

            <element in="root">
                <element-ignore in="child">
                    <element/>
                </element-ignore>
            </element>

Output

<root>
    <english>one</english>
    <english>ten</english>
    <english>hundred</english>
    <english>two</english>
    <english>twenty</english>
</root>

---

Ignore a subtree, with a condition of self node

Ignore node /root/child when the value of its attribute @key is 1.

            <element in="root">
                <element-ignore in="child" if="@key=1"/>
            </element>

Output

<root>
    <child key="2">
        <english>two</english>
        <english>twenty</english>
    </child>
</root>

---

Ignore a subtree, with a condition of child nodes

Ignore node /root/child when the value of at least one of its children starts with letter 'h'.

            <element in="root">
                <element-ignore in="child" if="english[starts-with(text(),'h')]"/>
            </element>

Output

<root>
    <child key="2">
        <english>two</english>
        <english>twenty</english>
    </child>
</root>

---

Create a new element

Create a new element under current element /root/child.

            <element in="root">
                <element in="child">
                    <element-create>new_element('newChild', 'myValue')</element-create>
                </element>
            </element>

Output

<root>
    <child key="1">
        <english>one</english>
        <english>ten</english>
        <english>hundred</english>
        <newChild>myValue</newChild>
    </child>
    <child key="2">
        <english>two</english>
        <english>twenty</english>
        <newChild>myValue</newChild>
    </child>
</root>

---

Join two data views

Copy subtree of view 'anotherView' matching the attribute @key of current element /root/child of current view.

            <element in="root">
                <set variable="anotherView">view('anotherView')/anotherRoot/anotherChild</set>
                <element in="child">
                    <!-- current() refers to the current context (i.e. the element being created), while . refers to <anotherChild> -->
                    <element-create>$anotherView[@anotherKey = current()/../@key]/french</element-create>
                </element>
            </element>

Output

<root>
    <child key="1">
        <english>one</english>
        <english>ten</english>
        <english>hundred</english>
        <french>un</french>
        <french>dix</french>
        <french>cent</french>
    </child>
    <child key="2">
        <english>two</english>
        <english>twenty</english>
        <french>deux</french>
        <french>vingt</french>
    </child>
</root>

---

Join two data views (with hash table)

Same as previous example, but using a hash table (may significantly improve execution time).

            <element in="root">
                <set variable="anotherView" index="@anotherKey">view('anotherView')/anotherRoot/anotherChild</set>
                <element in="child">
                    <element-create>find($anotherView, ../@key)/french</element-create>
                </element>
            </element>

Output

<root>
    <child key="1">
        <english>one</english>
        <english>ten</english>
        <english>hundred</english>
        <french>un</french>
        <french>dix</french>
        <french>cent</french>
    </child>
    <child key="2">
        <english>two</english>
        <english>twenty</english>
        <french>deux</french>
        <french>vingt</french>
    </child>
</root>

---

Join two data views (with indexed cache)

Same as previous example, but querying the index of the cache of view 'anotherView' (may be useful if view 'anotherView' is too large to fit into memory).

            <element in="root">
                <element in="child">
                    <element-create>view_path('anotherView', concat('/anotherRoot/anotherChild[@anotherKey="',../@key,'"]'))/*/anotherChild/french</element-create>
                </element>
            </element>

Output

<root>
    <child key="1">
        <english>one</english>
        <english>ten</english>
        <english>hundred</english>
        <french>un</french>
        <french>dix</french>
        <french>cent</french>
    </child>
    <child key="2">
        <english>two</english>
        <english>twenty</english>
        <french>deux</french>
        <french>vingt</french>
    </child>
</root>

Note that the XPath is provided as a string in order to be evaluated by view 'anotherView', rather than being evaluated by the current view. See also IndexedCache plugin parameters.

---

Sort elements

Sort elements <child> by their number of child elements.

            <element in="root">
                <element-ignore in="child"/>
                <element-create>sort_by_number(../child, 'count(english)')</element-create>
            </element>

Output

<root>
    <child key="2">
        <english>two</english>
        <english>twenty</english>
    </child>
    <child key="1">
        <english>one</english>
        <english>ten</english>
        <english>hundred</english>
    </child>
</root>

Note that the XPath is provided as a string in order to be evaluated by the function sort_by_number(). Note that Lavoisier will have to load all the data in memory in order to process this template.

---

Group elements

Group elements <english> by the first letter of their text. Grouping element in streaming is only possible when these elements are sorted according to the grouping criteria. Since the elements are not sorted, we will need to chain 2 templates for this example.

            <element in="root">
                <element-ignore in="child"/>
                <element-create>sort_by_string(../child/english, 'text()')</element-create>
            </element>

            <element in="root">
                <element-create-as-parent out="group" group-by="substring(text(),1,1)">
                    <element in="english"/>
                </element-create-as-parent>
            </element>

Output

<root>
    <group>
        <english>hundred</english>
    </group>
    <group>
        <english>one</english>
    </group>
    <group>
        <english>ten</english>
        <english>twenty</english>
        <english>two</english>
    </group>
</root>