An exception is thrown when no results are generated due to a division by zero in JavaParserMain.scala at line 60

[balfroim]

In this file, there is an instruction that shows the percentage of failed results compared to the total number of results generated. However, the total can be zero. It would be really helpful to have a message that says that no results have been generated, as it can be quite confusing to encounter a "dividing by zero" exception (see below) when using the tool for the first time.

java.lang.ArithmeticException: / by zero
	at com.virtuslab.semanticgraphs.javaparser.JavaParserMain$.generateSemanticGraphFiles(JavaParserMain.scala:60)
	at org.virtuslab.semanticgraphs.analytics.cli.ScgCli.generate(ScgCli.scala:59)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at picocli.CommandLine.executeUserObject(CommandLine.java:2066)
	at picocli.CommandLine.access$1500(CommandLine.java:148)
	at picocli.CommandLine$RunLast.executeUserObjectOfLastSubcommandWithSameParent(CommandLine.java:2461)
	at picocli.CommandLine$RunLast.handle(CommandLine.java:2453)
	at picocli.CommandLine$RunLast.handle(CommandLine.java:2415)
	at picocli.CommandLine$AbstractParseResultHandler.execute(CommandLine.java:2273)
	at picocli.CommandLine$RunLast.execute(CommandLine.java:2417)
	at picocli.CommandLine.execute(CommandLine.java:2170)
	at org.virtuslab.semanticgraphs.analytics.cli.ScgCli$.main(ScgCli.scala:335)
	at org.virtuslab.semanticgraphs.analytics.cli.ScgCli.main(ScgCli.scala)