解析Javadoc时链接的全限定类名

在注释处理器中解析Javadoc时，我们可以首先创建一个ImportTree，并使用它来确定由LinkTree#getReference()返回的ReferenceTree的FQCN，即{@link signature label}中的FQCN.我已经在10万分之一的情况下实现了这一点.伪码如下:

public class ExampleProcessor extends AbstractProcessor {

    private DocTrees docTrees;

    private Trees trees;

    @Override
    public synchronized void init(final ProcessingEnvironment processingEnv) {
        super.init(processingEnv);
        docTrees = DocTrees.instance(processingEnv);
        trees = Trees.instance(processingEnv);
    }

    private void scanDocTree(Element element) {
        Map<String, String> imports = collectElementImports(element);
        ExampleContext context = new ExampleContext(imports);
        DocCommentTree tree = docTrees.getDocCommentTree(element);
        ExampleDocTreeVisitor visitor = new ExampleDocTreeVisitor();
        tree.accept(visitor, context);
    }

    private static final class ExampleDocTreeVisitor<Void, ExampleContext>
            extends SimpleDocTreeVisitor<Void, ExampleContext> {

        @Override
        public Void visitLink(LinkTree linkTree, final ExampleContext context) {
            String signature = linkTree.getReference().getSignature();
            String fqcn = context.imports.get(signature);
            // ...
            return super.visitLink(node, data);
        }

    }

    private Map<String, String> collectElementImports(Element element) {
        ImportCollectingTreeScanner scanner = new ImportCollectingTreeScanner();
        TreePath treePath = trees.getPath(element);
        scanner.scan(treePath.getCompilationUnit(), null);
        return scanner.imports;
    }

    private static final class ImportCollectingScanner
            extends TreeScanner<Object, Trees> {

        private final Map<String, String> imports = new HashMap<>();

        @Override
        public Object visitImport(ImportTree importTree, Trees trees) {
            Tree qualifiedIdentifier = importTree.getQualifiedIdentifier();
            String qualifiedClassName = qualifiedIdentifier.toString();
            String simpleClassName = qualifiedClassName.substring(qualifiedClassName.lastIndexOf('.') + 1);
            imports.put(simpleClassName, qualifiedClassName);
            return super.visitImport(importTree, trees);
        }

    }

}

学分

• @piotr-p-karwaz为ImportTree个提示
• Andi's blog关于如何在批注处理器中提取ImportTree