java.lang.NullPointerException
    at de.upb.patternspecification.metamodel.PSSetFragmentSizeExpression.firePropertyChange(PSSetFragmentSizeExpression.java:127)
    at de.uni_paderborn.fujaba.asg.ASGElement.firePropertyChange(ASGElement.java:1156)
    at de.uni_paderborn.fujaba.asg.ASGElement.firePropertyChange(ASGElement.java:1193)
    at de.upb.patternspecification.metamodel.PSSetFragmentSizeExpression.setOperator(PSSetFragmentSizeExpression.java:120)
    at de.upb.pose.re.generator.factory.MetamodelFactory.createPSSetFragment(MetamodelFactory.java:118)
    at de.upb.pose.re.generator.TransformationVisitor.visit(TransformationVisitor.java:294)
    at de.upb.pose.re.generator.TransformationVisitor.visit(TransformationVisitor.java:136)
    at de.upb.pose.re.generator.TransformationVisitor.<init>(TransformationVisitor.java:74)
    at de.upb.pose.re.generator.Generator.start(Generator.java:66)
    at de.upb.pose.re.ui.tools.wizards.GenerateWizard.performFinish(GenerateWizard.java:40)
    at org.eclipse.jface.wizard.WizardDialog.finishPressed(WizardDialog.java:811)
    at org.eclipse.jface.wizard.WizardDialog.buttonPressed(WizardDialog.java:430)
    at org.eclipse.jface.dialogs.Dialog$2.widgetSelected(Dialog.java:624)
    at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:234)
    at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4066)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3657)
    at org.eclipse.jface.window.Window.runEventLoop(Window.java:825)
    at org.eclipse.jface.window.Window.open(Window.java:801)
    at de.upb.pose.re.ui.tools.actions.GenerateAction.run(GenerateAction.java:65)
    at org.eclipse.ui.internal.PluginAction.runWithEvent(PluginAction.java:251)
    at org.eclipse.ui.internal.WWinPluginAction.runWithEvent(WWinPluginAction.java:229)
    at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:584)
    at org.eclipse.jface.action.ActionContributionItem.access$2(ActionContributionItem.java:501)
    at org.eclipse.jface.action.ActionContributionItem$5.handleEvent(ActionContributionItem.java:411)
    at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4066)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3657)
    at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2629)
    at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2593)
    at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2427)
    at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:670)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
    at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:663)
    at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
    at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:115)
    at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:369)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:619)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:574)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1407)
    at org.eclipse.equinox.launcher.Main.main(Main.java:1383)