/* * Copyright (c) 2000 David Flanagan.  All rights reserved. * This code is from the book Java Examples in a Nutshell, 2nd Edition. * It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied. * You may study, use, and modify it for any non-commercial purpose. * You may distribute it non-commercially as long as you retain this notice. * For a commercial use license, or to purchase the book (recommended), * visit http://www.davidflanagan.com/javaexamples2. */package com.davidflanagan.examples.reflect;import java.lang.reflect.*;/** A program that displays a class synopsis for the named class */public class ShowClass {    /** The main method.  Print info about the named class */    public static void main(String[] args) throws ClassNotFoundException {        Class c = Class.forName(args[0]);        print_class(c);    }        /**     * Display the modifiers, name, superclass and interfaces of a class     * or interface. Then go and list all constructors, fields, and methods.     **/    public static void print_class(Class c)    {        // Print modifiers, type (class or interface), name and superclass.        if (c.isInterface()) {            // The modifiers will include the "interface" keyword here...            System.out.print(Modifier.toString(c.getModifiers()) + " " + 			     typename(c));        }        else if (c.getSuperclass() != null) {            System.out.print(Modifier.toString(c.getModifiers()) + " class " +			     typename(c) +			     " extends " + typename(c.getSuperclass()));	}        else {            System.out.print(Modifier.toString(c.getModifiers()) + " class " +			     typename(c));	}	        // Print interfaces or super-interfaces of the class or interface.        Class[] interfaces = c.getInterfaces();        if ((interfaces != null)&& (interfaces.length > 0)) {            if (c.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(" {");            // Begin class member listing.	        // Now look up and display the members of the class.        System.out.println("  // Constructors");        Constructor[] constructors = c.getDeclaredConstructors();        for(int i = 0; i < constructors.length; i++)   // Display constructors.            print_method_or_constructor(constructors[i]);	        System.out.println("  // Fields");        Field[] fields = c.getDeclaredFields();           // Look up fields.        for(int i = 0; i < fields.length; i++)            // Display them.            print_field(fields[i]);	        System.out.println("  // Methods");        Method[] methods = c.getDeclaredMethods();        // Look up methods.        for(int i = 0; i < methods.length; i++)           // Display them.            print_method_or_constructor(methods[i]);	        System.out.println("}");             // End class member listing.    }        /** Return the name of an interface or primitive type, handling arrays. */    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;    }        /** Return a string version of modifiers, handling spaces nicely. */    public static String modifiers(int m) {        if (m == 0) return "";        else return Modifier.toString(m) + " ";    }        /** Print the modifiers, type, and name of a field */    public static void print_field(Field f) {        System.out.println("  " + modifiers(f.getModifiers()) +			   typename(f.getType()) + " " + f.getName() + ";");    }        /**     * Print the modifiers, return type, name, parameter types and exception     * type of a method or constructor.  Note the use of the Member interface     * to allow this method to work with both Method and Constructor objects     **/    public static void print_method_or_constructor(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(";");    }}