There are several ways to represent the mapping between Source Device Item property and Target Device Item property. The different ways depends on the types of the properties.

• When the properties have similar types. In this situation should be used XML attributes of the XML elements. These XML attributes are: "sourceValue" and "targetValue". The "sourceValue" holds the simple value of the Source Device Item property. The "targetValue" holds the simple value of the Target Device Item property.

  <value-mapping>

    <value sourceValue="1" targetValue="true" />

    <value sourceValue="0" targetValue="false" />

  </value-mapping>

• When the property value is complex object value. For example map, collection, reference, script expression, etc. In this situation the corresponding child elements are used: <target-value> and <source-value>. The <target-value> holds the complex object value representation of the Target Device Item property. The <source-value> holds the complex object value representation of the Source Device Item property. These XML elements holds the property representation and have the following XML attributes:
  • "script" – this is optional XML attribute. This attribute holds script expression that should be evaluated. On Scripting in Mapping page there is detailed information about the scripting in XML mapping.
  • "ref" – this is an optional XML attribute. This attribute holds reference value. The possible values for this attribute are:
  • "sourceValue" – holds the reference to the Source Device Item property.
  • "targetValue" – holds the reference to the Target Device Item property.
  • "targetOperation" – holds the reference to the Target Device Item operation.
  • "returnValue" – holds the reference to the returned value of the Source Device Item operation.
  • "xsi:nil" – this is an optional XML attribute. It is used with value "true" and represents the null value. If the value of this attribute is set to "false", the property must not be null and must have a value. This value should be presented by one of the supported ways.

If the property value is map, collection, array, etc, then the representation of the property should use one of the child elements <map-value> or <array-value>. More information about the XML complex object value representation can be found in "Complex Object Value" section of the Mapping XML Value Representation guide.

<read>

  <target-value>

    <map-value>

      <element key="unit">

        <map-value>

          <element key="symbol" value="&#176;" />

        </map-value>

      </element>

      <element key="value">

        <map-value>

          <element key="value" script="#{sourceValue} * 2" />

        </map-value>

      </element>

    </map-value>

  </target-value>

</read>