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NPE when serializing an in-memory model [message #1122115]

Tue, 01 October 2013 08:42

Lars Martin

Messages: 24
Registered: July 2009

Junior Member

I try to serialize an in-memory model thus no valid underlaying resource and URI exist.

java.lang.NullPointerException
	at org.eclipse.xtext.ui.editor.formatting.PreferenceStoreWhitespaceInformationProvider.getLineSeparatorPreference(PreferenceStoreWhitespaceInformationProvider.java:56)
	at org.eclipse.xtext.ui.editor.formatting.PreferenceStoreWhitespaceInformationProvider.getLineSeparatorInformation(PreferenceStoreWhitespaceInformationProvider.java:46)
	at org.eclipse.xtext.formatting.impl.AbstractDeclarativeFormatter.getLineSeparatorInfo(AbstractDeclarativeFormatter.java:114)
	at org.eclipse.xtext.formatting.impl.AbstractDeclarativeFormatter.createFormattingConfig(AbstractDeclarativeFormatter.java:81)
	at org.eclipse.xtext.formatting.impl.AbstractDeclarativeFormatter.getConfig(AbstractDeclarativeFormatter.java:92)
	at org.eclipse.xtext.formatting.impl.AbstractDeclarativeFormatter.createFormatterStream(AbstractDeclarativeFormatter.java:75)
	at org.eclipse.xtext.serializer.impl.Serializer.serialize(Serializer.java:103)
	at org.eclipse.xtext.serializer.impl.Serializer.serialize(Serializer.java:122)
	at org.eclipse.xtext.serializer.impl.Serializer.serialize(Serializer.java:51)

The model is generated on the fly:

IParseResult parseResult = parser.parse(new StringReader("..."));
Model element = parseResult.getRootASTElement();
...
serializer.serialize(element);

Is this supposed to work?

Regards, Lars M.

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Re: NPE when serializing an in-memory model [message #1122143 is a reply to message #1122115]

Tue, 01 October 2013 09:10

Christian Dietrich

Messages: 14664
Registered: July 2009

Senior Member

Hi,

i guess you need at least a fake resource with a fake uri. (at least when you run this code from ui)
i am not sure if this is to be considered as a bug or not.

e.g.

ResourceSet rs = injector.getInstance(ResourceSet.class);
		Resource r = rs.createResource(URI.createURI("fake.mydsl"));
		r.getContents().add(model);
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		r.save(baos, SaveOptions.defaultOptions().toOptionsMap());
		String content = baos.toString("UTF-8");

or you bind a more nullsafe PreferenceStoreWhitespaceInformationProvider

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: NPE when serializing an in-memory model [message #1122166 is a reply to message #1122143]

Tue, 01 October 2013 09:35

Moritz Eysholdt

Messages: 161
Registered: July 2009
Location: Kiel, Germany

Senior Member

A model is always expected to have a resource. And as Christian suggested, the URI doesn't need to represent an actual file in the file system. It's a Unified Resource Identifier after all and not a Unified Resource Locator (URI vs. URL) Smile