Experimental -> Tools -> Add Banner: Exception

Prerequisites

• Put an X between the brackets on this line if you have done all of the following:
  • Running the latest version of Constellation
  • Attached the Support Package via Help > Support Package
  • Checked the FAQs: https://github.com/constellation-app/constellation/wiki/FAQ
  • Checked that your issue isn’t already filed: https://github.com/constellation-app/constellation/issues
  • Checked that there is not already a module that provides the described functionality: https://github.com/constellation-app/constellation/wiki/Catalogue-of-Repositories

Description

Adding a banner causes the below exception

java.lang.Exception: No I/O provider found for object type au.gov.asd.tac.constellation.graph.schema.visual.attribute.objects.Banner, attribute ImmutableAttribute[id=57;type=banner;label=banner;description=banner;elementType=Metadata;defaultValue=null]
	at au.gov.asd.tac.constellation.graph.file.io.GraphJsonWriter.writeElements(GraphJsonWriter.java:386)
[catch] at au.gov.asd.tac.constellation.graph.file.io.GraphJsonWriter.writeGraphToStream(GraphJsonWriter.java:261)
	at au.gov.asd.tac.constellation.graph.file.io.GraphJsonWriter.writeGraphToZip(GraphJsonWriter.java:168)
	at au.gov.asd.tac.constellation.graph.file.io.GraphJsonWriter.writeGraphToZip(GraphJsonWriter.java:144)
	at au.gov.asd.tac.constellation.graph.file.io.GraphJsonWriter.writeGraphToZip(GraphJsonWriter.java:135)
	at au.gov.asd.tac.constellation.graph.interaction.plugins.io.AutosaveGraphPlugin.execute(AutosaveGraphPlugin.java:94)
	at au.gov.asd.tac.constellation.plugins.templates.SimplePlugin.run(SimplePlugin.java:68)
	at au.gov.asd.tac.constellation.graph.node.plugins.DefaultPluginEnvironment.executePluginNow(DefaultPluginEnvironment.java:219)
	at au.gov.asd.tac.constellation.plugins.PluginExecution.executeNow(PluginExecution.java:310)
	at au.gov.asd.tac.constellation.graph.interaction.plugins.io.Autosaver$1.run(Autosaver.java:113)

Steps to Reproduce

1. New graph -> draw mode, add 3 nodes, select 1
2. Add banner

Expected behaviour: A banner to be added

Actual behaviour: Exception, and that is all

Reproduces how often: 30%

Additional Information

Found using .exe v2.0 rc2

[formalhaut69]

This issue is really odd. I’ve done a bit of analysis and I’ve noticed that the BannerIOProvider is being registered properly because you can see it in the list of all of the providers within the getProviders() method in AbstractGraphIOProvider.

But whats strange is that when you call the getProviders() method from another class, for example in the GraphJsonWriter constructor the BannerIOProvider is not returned. I’ll do some more analysis though and see what else I can find.

[cygnus-x-1]

I don’t think you necessarily need to implement convertFromString. Broadly, for an IOProvider to work, you need to define a way to serialize an object (in this case a Banner) to and from JSON in the IOProvider class. I suspect convertToString is offloading the work to the Banner class in this case, but it could just as easily be done in the IOProvider class.