Question

我正在开发一个项目，该项目需要根据指定的语言（语言只有函数定义）生成Java类。并且JvmModelInferrer / IGenerater需要隐式地从java项目调用。

遵循帖子How to invoke Xtext parser/JvmModelInferrer from a Java project中给出的步骤，但遗憾的是EclipseResourceFileSystemAccess2.generateFile()正在投掷NullPointerException。

用于生成的代码：

    public class Generator {
    private  static IGenerator generator;

    public static void main(String[] args) {

        // this line registers the EMF for our DSL
        Injector injector = new RequestDslStandaloneSetup().createInjectorAndDoEMFRegistration();
        ResourceSet rs = new ResourceSetImpl();
        File file = new File(
                "D:/Xtext/XtextFormIntegration/runtime-XtextFormNC/XtextFormCar/lang.request");
        Resource resource = rs.getResource(URI.createURI(file.toURI().toString()), true);

        //setup the generator
        generator = injector.getInstance(IGenerator.class);

        //setup the file system access
        final EclipseResourceFileSystemAccess2 fsa = new EclipseResourceFileSystemAccess2();


        generator.doGenerate(resource, fsa);

       }
    }

例外是：

Exception in thread "main" java.lang.NullPointerException
    at org.eclipse.xtext.builder.EclipseResourceFileSystemAccess2.generateFile(EclipseResourceFileSystemAccess2.java:156)
    at org.eclipse.xtext.generator.AbstractFileSystemAccess.generateFile(AbstractFileSystemAccess.java:75)
    at org.eclipse.xtext.xbase.compiler.JvmModelGenerator._internalDoGenerate(JvmModelGenerator.java:201)
    at org.eclipse.xtext.xbase.compiler.JvmModelGenerator.internalDoGenerate(JvmModelGenerator.java:1756)
    at org.eclipse.xtext.xbase.compiler.JvmModelGenerator.doGenerate(JvmModelGenerator.java:181)
    at de.itemis.utils.jface.viewers.Generator.main(Generator.java:41)

需要您帮助解决上述问题。

在期待中感谢你。

Answer 1

EclipseResourceFileSystemAccess2只能在完全初始化的Eclipse环境（包括工作空间等）中使用。如果你想编写一个独立的应用程序（一个带有普通main方法的类），你应该从注入器获得一个IFileSystemAccess实例，类似于你对生成器所做的那样。

Answer 2

以下代码适用于JavaIoFileSystemAccess和IEncodingProvider。

public class Generator {

    private  static IGenerator generator;

    public static void main(String[] args) {

        // this line registers the EMF for our DSL
        Injector injector = new MyDslStandaloneSetup().createInjectorAndDoEMFRegistration();
        ResourceSet rs = new ResourceSetImpl();
        File file = new File(
                "D:/Xtext/asap.dsl");
        Resource resource = rs.getResource(URI.createURI(file.toURI().toString()), true);

        //setup the generator
        generator = injector.getInstance(IGenerator.class);

        //setup the file system access
        final JavaIoFileSystemAccess jfsa = new JavaIoFileSystemAccess();
        jfsa.setOutputPath("Test");
        Guice.createInjector(new AbstractGenericModule() {

            public Class<? extends IEncodingProvider> bindIEncodingProvider() {
                return IEncodingProvider.Runtime.class;
            }

        }).injectMembers(jfsa);

        generator.doGenerate(resource, jfsa);       
}

}

感谢。

调用JvmModelInferrer / Generator以从Java项目生成代码时出现NullPointerException

2 个答案: