public
    @Override
    Object get(CompoundName name, Map<String, String> context,
               com.yahoo.processing.request.Properties substitution) {
        if (!properties.containsKey(name)) return super.get(name, context, substitution);
        return properties.get(name);
    }
Return true if this value should be set in this map, false if the set should be propagated instead
This default implementation always returns true.
container-core/src/main/java/com/yahoo/processing/request/properties/PropertyMap.java