I'm trying to construct a container that takes an XML fragment as a parameter value.
I've tried two approaches to this, and both result in exceptions (possibly due to
limitations in the Microstar XML parser, or laxity in my attempt to use XML).
If I use
public MyChannel extends WirelessChannel {
// ...
public Parameter pModifiers;
// ...
public MyContainer(CompositeEntity container, String name)
throws IllegalActionException {
super(container, name);
// ...
pModifiers = new Parameter(this, "modifiers");
pModifiers.setExpression("<modifiers/>");
pModifiers.setTypeEquals(BaseType.XMLTOKEN);
}
public void attributeChanged(Attribute attribute)
throws IllegalActionException {
if (attribute == pModifiers);
Document doc;
try {
doc = ((XMLToken) pModifiers.getToken()).getDomTree();
}
catch (Exception e) {
// Results in exception here;
// the parser gets confused when it hits the first "<"
}
}
}
then an exception occurs while building the Vergil palette that contains my entity:
the AElfred parser tries to interpret the value of the parameter with name "modifiers"
and gets confused, because "<" isn't a valid token in an XML attribute. (The same
thing happens if I set the type of pModifiers to BaseType.STRING and attempt to parse
it on my own.) However, if I use
public MyChannel extends WirelessChannel {
// ...
public Parameter pModifiers;
// ...
public MyContainer(CompositeEntity container, String name)
throws IllegalActionException {
super(container, name);
// ...
pModifiers = new Parameter(this, "modifiers");
pModifiers.setToken(new XMLToken("<modifiers/>"));
pModifiers.setTypeEquals(BaseType.XMLTOKEN);
}
public void attributeChanged(Attribute attribute)
throws IllegalActionException {
if (attribute == pModifiers);
Document doc;
try {
doc = ((XMLToken) pModifiers.getToken()).getDomTree();
}
catch (Exception e) {
// Results in exception here;
// the parser gets confused when it hits the first "<"
}
}
}
then Vergil startup goes okay, but I get an XML parsing exception when I try to update
the "modifiers" parameter (say, from "<modifiers/> to "<modifiers></modifiers>", which
should be semantically equivalent).
Is it possible to include an XML expression as a mutable part of an entity's
configuration, just as string or record parameters are mutable? (Keep in mind that
the XML expression isn't MoML.) I'd be happy to treat the expression as a plain
string and do the parsing myself, but replacing all of the tag delimiters with escape
sequences (e.g. < or >) would be inconvenient.
Thanks,
Andy Z.
-----
Andrew Zimdars
Modeling, Simulation, and Information Sciences (Org. ABCS)
Advanced Technology Center, Lockheed Martin Space Systems Co.
Bldg. 153, Col. 2J4
1111 Lockheed Martin Way, Sunnyvale, CA 94089
w: 408.742.2111 m: 510.915.0662
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