Antlr v3：在解析树中打印给定节点的子树

Question

I'm current working on a project and I came to the point where I need to extract all methods from a given Java source code. I need to implement it in antlr v3 but I came to a dead-end since the api documentation doesn't clarify how can one do that. I've also searched through the official book but still with no success. Any ideas?

EDIT: I found that in antlr v4 this can be done as:

import org.antlr.v4.runtime.*;
import org.antlr.v4.runtime.tree.*;
import java.io.*;


public class Main {
    public static void main(String[] args) throws IOException {
        ANTLRInputStream input = new ANTLRInputStream(System.in);
        JavaLexer lexer = new JavaLexer(input);
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        JavaParser parser = new JavaParser(tokens);

        ParseTree tree = parser.compilationUnit();
        ParseTreeWalker walker = new ParseTreeWalker();
        MethodPrinter printer = new MethodPrinter();
        walker.walk(printer, tree);
        for (String method : printer.methods)
            System.out.println(method);
    }
}

where Method printer is implemented as:

import org.antlr.v4.runtime.tree.TerminalNode;
import java.util.ArrayList;

public class MethodPrinter extends JavaBaseListener {
    boolean inMethod;
    String currentMethod;
    ArrayList<String> methods;

    public MethodPrinter() {
        inMethod = false;
        methods = new ArrayList<String>();
    }

    public void enterMethodDeclaration(JavaParser.MethodDeclarationContext ctx) {
        inMethod = true;
        currentMethod = "";
    }

    public void exitMethodDeclaration(JavaParser.MethodDeclarationContext ctx) {
        inMethod = false;
        methods.add(currentMethod);
    }

    public void visitTerminal(TerminalNode node) {
        if (inMethod)
            currentMethod += node.getText() + " ";
    }
}

How this can be implemented in antlr v3 ?

Answer 1

Java source code has to be encapsulated in a class.
You can use reflection to get all the methods in a given class.

...
Class cl = Class.forName("com.example.test.MyClass");
// or cl = someObject.getClass();
List<Method> methods = cl.getDeclaredMethods(cl);
methods.addAll(cl.getMethods());
...

then you can use it a normal java list