ASF_20_SRC_AUTO/src/blocks/woody/samples/forms/carselector_form.xml

<?xml version="1.0" encoding="ISO-8859-1"?>
<!-- form used to illustrate programmatic changing of listbox content. -->
<wd:form
  xmlns:wd="http://apache.org/cocoon/woody/definition/1.0"
  xmlns:i18n="http://apache.org/cocoon/i18n/2.1">

  <wd:widgets>
    <wd:field id="make" required="true">
      <wd:label>Make:</wd:label>
      <wd:datatype base="string"/>
      <wd:selection-list src="cocoon:/cars" dynamic="true"/>
      <wd:on-value-changed>
        <javascript>
          java.lang.System.err.println("maker changed from " + event.oldValue + " to " + event.newValue);
          var value = event.source.value;
          var typewidget = event.source.parent.getWidget("type");
          if (value != null) {
            // Get the corresponding type list
            typewidget.setSelectionList("cocoon:/cars/" + value);
          } else {
            // Reset the value (will clear validation error)
            event.source.setValue(null);
            // Set an empty selection list
            typewidget.setSelectionList(new Packages.org.apache.cocoon.woody.datatype.EmptySelectionList("Select a maker first"));
          }
          // Always set the type value to null. Note that it will also fire an event on the "type"
          // widget if it already had a value.
          typewidget.setValue(null);
          
          // Fun with messages...
          var msg = event.source.parent.getWidget("message");
          if (value == null) {
            msg.value = "Yep. Choosing a maker is not that easy...";
          } else {
            if (event.oldValue == null) {
              msg.value = "Good. " + value + " makes good cars!";
            } else {
              msg.value = "Why not? " + value + " also makes good cars!";
            }
          }
        </javascript>
      </wd:on-value-changed>
    </wd:field>
  
    <wd:field id="type" required="true">
      <wd:label>Type:</wd:label>
      <wd:datatype base="string"/>
      <wd:selection-list>
        <wd:item value="">
          <wd:label>Select a maker first</wd:label>
        </wd:item>
      </wd:selection-list>
      <wd:on-value-changed>
        <javascript>
          java.lang.System.err.println("type changed to " + event.source.value);
          var value = event.source.value;
          var modelwidget = event.source.parent.getWidget("model");
          var makewidget = event.source.parent.getWidget("make");
          if (value != null) {
            modelwidget.setSelectionList("cocoon:/cars/" + makewidget.value + "/" + value);
          } else {
            // Reset the value (will clear validation error)
            event.source.setValue(null);
            // Set an empty selection list
            modelwidget.setSelectionList(new Packages.org.apache.cocoon.woody.datatype.EmptySelectionList("Select a type first"));
          }
          
          // Always set the model value to null. Note that it will also fire an event on the "model"
          // widget if it already had a value.
          modelwidget.setValue(null);
          
          // Fun with messages...
          if (value != null) {
            var msg = event.source.parent.getWidget("message");
            if (event.oldValue == null) {
              msg.value = "A " + makewidget.value + " " + value + " is a very good choice.";
            } else {
              msg.value = "So you prefer a " + value + " ?";
            }
          }
        </javascript>
      </wd:on-value-changed>
    </wd:field>
    
    <wd:field id="model" required="true">
      <wd:label>Model:</wd:label>
      <wd:datatype base="string"/>
      <wd:selection-list>
        <wd:item value="">
          <wd:label>Select a type first</wd:label>
        </wd:item>
      </wd:selection-list>
      <wd:on-value-changed>
        <javascript>
          var value = event.source.value;
          if (value != null) {
            event.source.parent.getWidget("message").setValue("Model " + value + " is a great car!");
          } else {
            // Reset value
            event.source.value = null;
          }
        </javascript>
      </wd:on-value-changed>
    </wd:field>
  
    <wd:output id="message">
      <wd:datatype base="string"/>
    </wd:output>
  
  </wd:widgets>

</wd:form>