public void set(CompoundName name, Object value, Map<String, String> context) {
        if (shouldSet(name, value))
            properties.put(name, value);
        else
            super.set(name, value, context);
    }
A HashMap backing of Properties.
<p>
When this is cloned it will deep copy not only the model object map, but also each
clonable member inside the map.
<p>
Subclassing is supported, a hook can be implemented to provide conditional inclusion in the map.
By default - all properties are accepted, so set is never propagated.
<p>
This class is not multithread safe.

@author bratseth
container-core/src/main/java/com/yahoo/processing/request/properties/PropertyMap.java