This class overrides some of the methods in IORelation to ensure that
TypedIOPorts are only connected to TypedIOPorts. I.e., Instances of
TypedIORelation can only be linked to instances of TypedIOPort.
Derived classes may further constrain this to subclasses of TypedIOPort.
Such derived classes should override the protected method _checkPort()
to throw an exception.
<p>
To link a TypedIOPort to a TypedIORelation, use the link() or
liberalLink() method in the TypedIOPort class. To remove a link,
use the unlink() method.
<p>
The container for instances of this class can only be instances of
TypedCompositeActor. Derived classes may wish to further constrain the
container to subclasses of TypedComponentEntity. To do this, they should
override the _checkContainer() method.
Yuhong Xiong
$Id: TypedIORelation.java 70398 2014-10-22 23:44:32Z cxh $
Ptolemy II 0.2
Green (yuhong)
Green (liuxj)