ShowClass.java Source code

Introduction

Here is the source code for ShowClass.java

Source

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

public class ShowClass {
    public static void main(String[] args) throws ClassNotFoundException {
        Class aClass = Class.forName("javax.swing.JComponent");
        if (aClass.isInterface()) {
            System.out.print(Modifier.toString(aClass.getModifiers()) + " " + typeName(aClass));
        } else if (aClass.getSuperclass() != null) {
            System.out.print(Modifier.toString(aClass.getModifiers()) + " class " + typeName(aClass) + " extends "
                    + typeName(aClass.getSuperclass()));
        } else {
            System.out.print(Modifier.toString(aClass.getModifiers()) + " class " + typeName(aClass));
        }

        Class[] interfaces = aClass.getInterfaces();
        if ((interfaces != null) && (interfaces.length > 0)) {
            if (aClass.isInterface())
                System.out.print(" extends ");
            else
                System.out.print(" implements ");
            for (int i = 0; i < interfaces.length; i++) {
                if (i > 0)
                    System.out.print(", ");
                System.out.print(typeName(interfaces[i]));
            }
        }

        System.out.println(" {");

        Constructor[] constructors = aClass.getDeclaredConstructors();
        for (int i = 0; i < constructors.length; i++)
            printMethodOrConstructor(constructors[i]);

        Field[] fields = aClass.getDeclaredFields();
        for (int i = 0; i < fields.length; i++)
            printField(fields[i]);

        Method[] methods = aClass.getDeclaredMethods();
        for (int i = 0; i < methods.length; i++)
            printMethodOrConstructor(methods[i]);

        System.out.println("}");
    }

    public static String typeName(Class t) {
        String brackets = "";
        while (t.isArray()) {
            brackets += "[]";
            t = t.getComponentType();
        }
        String name = t.getName();
        int pos = name.lastIndexOf('.');
        if (pos != -1)
            name = name.substring(pos + 1);
        return name + brackets;
    }

    public static String modifiers(int m) {
        if (m == 0)
            return "";
        else
            return Modifier.toString(m) + " ";
    }

    public static void printField(Field f) {
        System.out.println("  " + modifiers(f.getModifiers()) + typeName(f.getType()) + " " + f.getName() + ";");
    }

    public static void printMethodOrConstructor(Member member) {
        Class returntype = null, parameters[], exceptions[];
        if (member instanceof Method) {
            Method m = (Method) member;
            returntype = m.getReturnType();
            parameters = m.getParameterTypes();
            exceptions = m.getExceptionTypes();
            System.out.print(
                    "  " + modifiers(member.getModifiers()) + typeName(returntype) + " " + member.getName() + "(");
        } else {
            Constructor c = (Constructor) member;
            parameters = c.getParameterTypes();
            exceptions = c.getExceptionTypes();
            System.out.print("  " + modifiers(member.getModifiers()) + typeName(c.getDeclaringClass()) + "(");
        }

        for (int i = 0; i < parameters.length; i++) {
            if (i > 0)
                System.out.print(", ");
            System.out.print(typeName(parameters[i]));
        }
        System.out.print(")");
        if (exceptions.length > 0)
            System.out.print(" throws ");
        for (int i = 0; i < exceptions.length; i++) {
            if (i > 0)
                System.out.print(", ");
            System.out.print(typeName(exceptions[i]));
        }
        System.out.println(";");
    }
}