我正在使用 xtext 来构建我的 dsl，并且我添加了一个弹出操作，我现在需要的是当执行该操作以加载 AST 并转换它时，我尝试使用以下 coe 加载根 Ast 元素
/*Environment configuration*/
StandaloneSetup standalone = new StandaloneSetup();
standalone.setPlatformUri(workingPath);
Injector injector = new MyDslStandaloneSetup().createInjectorAndDoEMFRegistration();
XtextResourceSet resourceSet = injector.getInstance(XtextResourceSet.class);
resourceSet.addLoadOption(XtextResource.OPTION_RESOLVE_ALL, Boolean.TRUE);
/*File parsing*/
Resource resource = resourceSet.createResource(URI.createURI(uriPrefix + fileName));
InputStream in = new FileInputStream(workingPath + fileName);
resource.load(in, resourceSet.getLoadOptions());
if(resource.getContents().size() == 0) {
System.out.println("The file is empty: no folder has been generated");
return null;
}
Prog model = (Prog) resource.getContents().get(0);
return model;
但不要工作并引发此异常:
!MESSAGE Invalid property category path: ValidationPropertiesPage (bundle: org.eclipse.wst.xml.ui, propertyPage: org.eclipse.wst.xml.ui.propertyPage.project.validation)
org.eclipse.emf.ecore.resource.Resource$IOWrappedException: Content is not allowed in prolog.
at org.eclipse.emf.ecore.xmi.impl.XMLLoadImpl.load(XMLLoadImpl.java:195)
at org.eclipse.emf.ecore.xmi.impl.XMLResourceImpl.doLoad(XMLResourceImpl.java:240)
at org.eclipse.emf.ecore.resource.impl.ResourceImpl.load(ResourceImpl.java:1505)
at org.xtext.example.mydsl.ui.popup.actions.RunClass.getProg(RunClass.java:203)
at org.xtext.example.mydsl.ui.popup.actions.RunClass.run(RunClass.java:88)
at org.eclipse.ui.internal.PluginAction.runWithEvent(PluginAction.java:251)
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:1276)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3554)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3179)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1022)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:916)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:86)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:585)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:540)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:124)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:353)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:180)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:629)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:584)
at org.eclipse.equinox.launcher.Main.run(Main.java:1438)
at org.eclipse.equinox.launcher.Main.main(Main.java:1414)
Caused by: org.xml.sax.SAXParseExceptionpublicId: platform:/resource/prova/a.myDsl; systemId: platform:/resource/prova/a.myDsl; lineNumber: 4; columnNumber: 1; Content is not allowed in prolog.
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:198)
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(ErrorHandlerWrapper.java:177)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:391)
at com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(XMLScanner.java:1404)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:1014)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:625)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:488)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:819)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:748)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:123)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1208)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:525)
at javax.xml.parsers.SAXParser.parse(SAXParser.java:392)
at org.eclipse.emf.ecore.xmi.impl.XMLLoadImpl.load(XMLLoadImpl.java:175)
... 34 more
我如何加载 ASt？
最佳答案
错误信息是这样的:
org.xml.sax.SAXParseException publicId:
platform:/resource/prova/a.myDsl; systemId: platform:/resource/prova/a.myDsl;
lineNumber: 4; columnNumber: 1; Content is not allowed in prolog
这意味着框架试图将您的 DSL 加载为 XML，但这将不起作用。这些错误的常见原因是文件扩展名 myDsl 未注册。
使用此调用会发生这种情况:
org.eclipse.xtext.resource.IResourceServiceProvider.Registry.INSTANCE.getExtensionToFactoryMap().put("myDsl", ...);
确保为您的 DSL 调用此方法。
此外，在编写 Eclipse 插件时，您不得使用独立设置。这样做会破坏很多全局变量并导致虚假错误。对于 Eclipse 插件，将使用 DSL 激活器 在您的 UI 包中搜索 *Activator.java。
其中有一个方法 getInjector() 应该被调用。
关于java - xtext 如何获取根 AST 元素，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/13624338/