Like Job has a
public <T extends JobProperty> T getProperty(Class<T> clazz)
and
public JobProperty getProperty(String className)

there should be similar methods for a Node
public <T extends NodeProperty> T getProperty(Class<T> clazz)
and
public NodeProperty getProperty(String className)

This makes it easier when you write your own NodeProperty and want to check if it is set on a node or not.