如何使用Java Tree Compiler API查找标识符的类型声明? [英] How do I find the type declaration of an identifier using the Java Tree Compiler API?

问题描述

我有一个变量/标识符的名称，例如x，以及JCCompilationUnit和

I have the name of a variable/identifier, say, x, and the JCCompilationUnit and Scope. Is there a way to find the type of x?

推荐答案

 public Symbol getSymbol(CompilationUnitTree cut, JCStatement stmt, List<JCExpression> typeParams, Name varName, List<JCExpression> args) {
    java.util.List<Type> typeSyms = getArgTypes(typeParams, cut, stmt);
    java.util.List<Type> argsSyms = getArgTypes(args, cut, stmt);
    final Scope scope = getScope(cut, stmt);
    Symbol t = contains(scope, typeSyms, varName, argsSyms); //first lookup scope for all public identifiers
    TypeElement cl = scope.getEnclosingClass();
    while (t == null && cl != null) { //lookup hierarchy for inacessible identifiers too
        t = contains(elementUtils.getAllMembers(cl), typeSyms, varName, argsSyms);
        final TypeMirror superclass = cl.getSuperclass();
        if (superclass != null) {
            cl = (TypeElement) ((Type) superclass).asElement();
        }
    }
    return t;
}

public Symbol getSymbol(Name varName, Symbol accessor, CompilationUnitTree cut, JCStatement stmt) {
    if (varName.contentEquals("class")) {
        Symbol javaLangClassSym = getSymbol(cut, stmt, null, elementUtils.getName("java.lang.Class"), null);
        JCIdent id = tm.Ident(javaLangClassSym);
        JCExpression mName = tm.Select(id, elementUtils.getName("forName"));
        JCLiteral idLiteral = tm.Literal(accessor.toString());
        JCMethodInvocation mi = tm.Apply(List.<JCExpression>nil(), mName, List.<JCExpression>of(idLiteral));
        Symbol s = getSymbol(mi, cut, stmt);
        return s;
    }
    accessor = getTypeSymbol(accessor);
    java.util.List<Symbol> enclosedElements = getEnclosedElements(accessor, cut, stmt);
    Symbol s = contains(enclosedElements, null, varName, null);
    return s;
}

我最终写了完整的具有解析方法的类.继承它，或传入TreeMaker(和其他参数)，可以将其设为静态.如果有人觉得值得，欢迎添加补丁.

I ended up writing a full class with resolving methods. Inheriting it, or passing in the TreeMaker (and other parameters) it can be made static. Should someone find it worthwile, a patch is welcome.

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