Can ASM method-visitors be used with interfaces?
- by Olaf Mertens
I need to write a tool that lists the classes that call methods of specified interfaces. It will be used as part of the build process of a large java application consisting of many modules. The goal is to automatically document the dependencies between certain java modules.
I found several tools for dependency analysis, but they don't work on the method level, just for packages or jars. Finally I found ASM, that seems to do what I need.
The following code prints the method dependencies of all class files in a given directory:
import java.io.*;
import java.util.*;
import org.objectweb.asm.ClassReader;
public class Test {
public static void main(String[] args) throws Exception {
File dir = new File(args[0]);
List<File> classFiles = new LinkedList<File>();
findClassFiles(classFiles, dir);
for (File classFile : classFiles) {
InputStream input = new FileInputStream(classFile);
new ClassReader(input).accept(new MyClassVisitor(), 0);
input.close();
}
}
private static void findClassFiles(List<File> list, File dir) {
for (File file : dir.listFiles()) {
if (file.isDirectory()) {
findClassFiles(list, file);
} else if (file.getName().endsWith(".class")) {
list.add(file);
}
}
}
}
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.commons.EmptyVisitor;
public class MyClassVisitor extends EmptyVisitor {
private String className;
@Override
public void visit(int version, int access, String name, String signature,
String superName, String[] interfaces) {
this.className = name;
}
@Override
public MethodVisitor visitMethod(int access, String name, String desc,
String signature, String[] exceptions) {
System.out.println(className + "." + name);
return new MyMethodVisitor();
}
}
import org.objectweb.asm.commons.EmptyVisitor;
public class MyMethodVisitor extends EmptyVisitor {
@Override
public void visitMethodInsn(int opcode, String owner, String name,
String desc) {
String key = owner + "." + name;
System.out.println(" " + key);
}
}
The Problem:
The code works for regular classes only! If the class file contains an interface, visitMethod is called, but not visitMethodInsn. I don't get any info about the callers of interface methods.
Any ideas?
