注释处理程序

Question

我有一个注释处理器的问题。

首先是我的源代码:

@SupportedAnnotationTypes("*")
@SupportedSourceVersion(SourceVersion.RELEASE_8)
public class TreeAnnotationProcessor extends AbstractProcessor{
  private Trees trees;
  private Tree tree;
  @Override
  public synchronized void init(ProcessingEnvironment processingEnv) {
    super.init(processingEnv);
    trees = Trees.instance(processingEnv);
  }
  @Override
  public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
    for (Element element : roundEnv.getRootElements()) {
      tree = trees.getTree(element);
    }
    return true;
  }
  public Tree getTree() {
    return tree;
  }
}

This Annotationprocessor收集编译器的树。在这个处理器中，一切都很好。如果我在编译过程之后调用函数getTree，那么树就没有完成。树(节点)的所有子节点都不在。

...
JavaCompiler.CompilationTask task = compiler.getTask(null, fileManager, null, null, null, compilationUnits);
TreeAnnotationProcessor treeAnnotationProcessor = new TreeAnnotationProcessor();
task.setProcessors(Collections.singletonList(treeAnnotationProcessor));
task.call();
Tree tree = treeAnnotationProcessor.getTree();
...

谢谢你的帮助。

Answer 1

我找到了一个解决方案。tree接口是由类com.sun.tools.javac.tree.JCTree实现的。这个类实现了一个克隆方法。当我使用此方法时，克隆在编译过程后完成:

@SupportedAnnotationTypes("*")
@SupportedSourceVersion(SourceVersion.RELEASE_8)
public class TreeAnnotationProcessor extends AbstractProcessor{
  private Trees trees;
  private Tree tree;
  @Override
  public synchronized void init(ProcessingEnvironment processingEnv) {
    super.init(processingEnv);
    trees = Trees.instance(processingEnv);
  }
  @Override
  public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
    for (Element element : roundEnv.getRootElements()) {
      tree = trees.getTree(element);
      try {
        Method cloneMethod = tree.getClass().getMethod("clone");
        Object cloneTree = cloneMethod.invoke(tree);
        this.tree = (Tree) cloneTree;
      } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
        e.printStackTrace();
      }
    }
    return true;
  }
  public Tree getTree() {
    return tree;
  }
}