</ruleset-ref>
    <ruleset-ref path='rulesets/naming.xml'>
        <rule-config name='ClassName'>
            <property name='regex' value='^[A-Z][\$a-zA-Z0-9]*$'/>
        </rule-config>
        <rule-config name='FieldName'>
            <property name='finalRegex' value='^[a-z][a-zA-Z0-9]*$'/>
            <property name='staticFinalRegex' value='^logger$|^[A-Z][A-Z_0-9]*$|^serialVersionUID$'/>
        </rule-config>

         * @param source The source value
         * @param fieldName A description of the field being interpolated. The implementation may use this to
         *                           log stuff.
         * @return The interpolated value.
         */
        String transform(String source, String fieldName);
    }

      if (varyFields.isEmpty()) return Headers.EMPTY

      val result = Headers.Builder()
      for (i in 0 until requestHeaders.size) {
        val fieldName = requestHeaders.name(i)
        if (fieldName in varyFields) {
          result.add(fieldName, requestHeaders.value(i))
        }
      }
      return result.build()
    }
  }

        <field xml.tagName="role-hint">
          <name>roleHint</name>
          <type>String</type>
          <description></description>
        </field>
        <field xml.tagName="field-name">
          <name>fieldName</name>
          <required>true</required>
          <type>String</type>
          <description>The field name which has this requirement.</description>
        </field>
      </fields>
    </class>

 * <li><code>merge<i>Classname</i>( <i>Classname</i> target, <i>Classname</i> source, boolean sourceDominant,
 * Map&lt;Object, Object&gt; context )</code> for each model class</li>
 * <li><code>merge<i>Classname</i>_<i>FieldName</i>( <i>Classname</i> target, <i>Classname</i> source, boolean
 * sourceDominant, Map&lt;Object, Object&gt; context )</code> for each field of each model class</li>

LiteralValue = "{" [ ElementList [ "," ] ] "}" .
ElementList  = KeyedElement { "," KeyedElement } .
KeyedElement = [ Key ":" ] Element .
Key          = FieldName | Expression | LiteralValue .
FieldName    = identifier .
Element      = Expression | LiteralValue .
</pre>

<p>
Unless the LiteralType is a type parameter,
its <a href="#Underlying_types">underlying type</a>