125 lines
3.5 KiB
Java
125 lines
3.5 KiB
Java
import java.util.*;
|
|
import java.lang.reflect.*;
|
|
|
|
/**
|
|
* This program uses reflection to print all features of a class.
|
|
* @version 1.1 2004-02-21
|
|
* @author Cay Horstmann
|
|
*/
|
|
public class ReflectionTest
|
|
{
|
|
public static void main(String[] args)
|
|
{
|
|
// read class name from command line args or user input
|
|
String name;
|
|
if (args.length > 0) name = args[0];
|
|
else
|
|
{
|
|
Scanner in = new Scanner(System.in);
|
|
System.out.println("Enter class name (e.g. java.util.Date): ");
|
|
name = in.next();
|
|
}
|
|
|
|
try
|
|
{
|
|
// print class name and superclass name (if != Object)
|
|
Class cl = Class.forName(name);
|
|
Class supercl = cl.getSuperclass();
|
|
String modifiers = Modifier.toString(cl.getModifiers());
|
|
if (modifiers.length() > 0) System.out.print(modifiers + " ");
|
|
System.out.print("class " + name);
|
|
if (supercl != null && supercl != Object.class) System.out.print(" extends "
|
|
+ supercl.getName());
|
|
|
|
System.out.print("\n{\n");
|
|
printConstructors(cl);
|
|
System.out.println();
|
|
printMethods(cl);
|
|
System.out.println();
|
|
printFields(cl);
|
|
System.out.println("}");
|
|
}
|
|
catch (ClassNotFoundException e)
|
|
{
|
|
e.printStackTrace();
|
|
}
|
|
System.exit(0);
|
|
}
|
|
|
|
/**
|
|
* Prints all constructors of a class
|
|
* @param cl a class
|
|
*/
|
|
public static void printConstructors(Class cl)
|
|
{
|
|
Constructor[] constructors = cl.getDeclaredConstructors();
|
|
|
|
for (Constructor c : constructors)
|
|
{
|
|
String name = c.getName();
|
|
System.out.print(" ");
|
|
String modifiers = Modifier.toString(c.getModifiers());
|
|
if (modifiers.length() > 0) System.out.print(modifiers + " ");
|
|
System.out.print(name + "(");
|
|
|
|
// print parameter types
|
|
Class[] paramTypes = c.getParameterTypes();
|
|
for (int j = 0; j < paramTypes.length; j++)
|
|
{
|
|
if (j > 0) System.out.print(", ");
|
|
System.out.print(paramTypes[j].getName());
|
|
}
|
|
System.out.println(");");
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Prints all methods of a class
|
|
* @param cl a class
|
|
*/
|
|
public static void printMethods(Class cl)
|
|
{
|
|
Method[] methods = cl.getDeclaredMethods();
|
|
|
|
for (Method m : methods)
|
|
{
|
|
Class retType = m.getReturnType();
|
|
String name = m.getName();
|
|
|
|
System.out.print(" ");
|
|
// print modifiers, return type and method name
|
|
String modifiers = Modifier.toString(m.getModifiers());
|
|
if (modifiers.length() > 0) System.out.print(modifiers + " ");
|
|
System.out.print(retType.getName() + " " + name + "(");
|
|
|
|
// print parameter types
|
|
Class[] paramTypes = m.getParameterTypes();
|
|
for (int j = 0; j < paramTypes.length; j++)
|
|
{
|
|
if (j > 0) System.out.print(", ");
|
|
System.out.print(paramTypes[j].getName());
|
|
}
|
|
System.out.println(");");
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Prints all fields of a class
|
|
* @param cl a class
|
|
*/
|
|
public static void printFields(Class cl)
|
|
{
|
|
Field[] fields = cl.getDeclaredFields();
|
|
|
|
for (Field f : fields)
|
|
{
|
|
Class type = f.getType();
|
|
String name = f.getName();
|
|
System.out.print(" ");
|
|
String modifiers = Modifier.toString(f.getModifiers());
|
|
if (modifiers.length() > 0) System.out.print(modifiers + " ");
|
|
System.out.println(type.getName() + " " + name + ";");
|
|
}
|
|
}
|
|
}
|