LoadClassJava

demo.txt

[jirka@private result]$ ls
ExecutableClass.class  Main.class  Spoustec.py  Spoustec.py~  TestovaciA.class  TestovaciB.class

[jirka@private result]$ python3 Spoustec.py 
fred
No such class Exception
TestovaciA
Hello from TestovaciA
TestovaciB
Hello from TestovaciB
asdf
No such class Exception

#### Upravená verze co nahrává pomocí reflexe a volá metodu main ####

[jirka@private result]$ tree
.
├── cz
│   ├── muni
│   │   ├── fi
│   │   │   ├── package.bluej
│   │   │   └── pb162
│   │   │       ├── package.bluej
│   │   │       └── task2
│   │   │           ├── BatteryPowered.class
│   │   │           ├── BatteryPowered.ctxt
│   │   │           ├── BatteryPowered.java
│   │   │           ├── Candle.class
│   │   │           ├── Candle.ctxt
│   │   │           ├── Candle.java
│   │   │           ├── Demo.class
│   │   │           ├── Demo.ctxt
│   │   │           ├── Demo.java
│   │   │           ├── Light.class
│   │   │           ├── Light.ctxt
│   │   │           ├── Light.java
│   │   │           ├── NightWatchman.class
│   │   │           ├── NightWatchman.ctxt
│   │   │           ├── NightWatchman.java
│   │   │           ├── package.bluej
│   │   │           ├── Torch.class
│   │   │           ├── Torch.ctxt
│   │   │           └── Torch.java
│   │   └── package.bluej
│   └── package.bluej
├── ExecutableClass.class
├── Main.class
├── Spoustec.py
├── Spoustec.py~
├── TestovaciA.class
├── TestovaciB.class
└── TestovaciC.class

5 directories, 30 files

[jirka@private result]$ python3 Spoustec.py 
cz.muni.fi.pb162.task2.Demo    
Night-watchman's equipment: None
Night-watchman's equipment: Candle with beam distance of 3 m
Night-watchman's equipment: Candle with beam distance of 5 m
Night-watchman's equipment: Torch with batteries. Beam distance: 10 m.
Night-watchman's equipment: Torch without batteries. Beam distance: 0 m.
TestovaciC
Hello from TestovaciC

empty.txt

this file is empty

ExecutableClass.java

/**
 * Created by IntelliJ IDEA.
 * User: jirka
 * Date: 11/4/11
 * Time: 7:16 PM
 * To change this template use File | Settings | File Templates.
 */
public interface ExecutableClass {
    public void execute();
}

Main.java

import javax.tools.JavaCompiler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Scanner;

/**
 * Created by IntelliJ IDEA.
 * User: jirka
 * Date: 11/4/11
 * Time: 6:59 PM
 * To change this template use File | Settings | File Templates.
 */
public class Main {
    public static void main(String[] args) throws InvocationTargetException, IllegalAccessException, ClassNotFoundException, NoSuchMethodException {
        Scanner s = new Scanner(System.in);
        ClassLoader classLoader = Main.class.getClassLoader();

        do {
            if (! s.hasNextLine()) {
                return;
            }

            String input = s.nextLine();

            if (input.equals("")) {
                return;
            }

                Class newClass = classLoader.loadClass(input);
                /** pokud můžu přidat rozhraní */
//                ExecutableClass e = (ExecutableClass) newClass.newInstance();
//                e.execute();

                /** pokud ne */
                /** kompilátor mi dá poznámku, že třída používá "unsafe operations, tak možná to dělám špatně,
                 * ale funguje to  ;) */
                Method method = newClass.getMethod("main", new Class[] {String[].class});
                Object e = null; //(ExecutableClass) newClass.newInstance();
                                 // protože http://www.javaworld.com/javaworld/javaqa/1999-07/06-qa-invoke.html
                method.invoke(e, new Object[] { new String[]{"arg1", "arg2"}});
        } while (true);
    }

}

Spoustec.py

__author__ = 'jirka'

import subprocess

p = subprocess.Popen(shell=True, args='java Main', stdin=subprocess.PIPE)
stdin = p.stdin

while True:
    i = input()

    stdin.write( (i + '\n').encode() );
    #stdin.flush()

    if i == '':
        break;
        
#p.wait()

TestovaciA.java

/**
 * Created by IntelliJ IDEA.
 * User: jirka
 * Date: 11/4/11
 * Time: 7:18 PM
 * To change this template use File | Settings | File Templates.
 */
public class TestovaciA implements ExecutableClass {
    public void execute() {
        System.out.println("Hello from TestovaciA");
    }
}

TestovaciB.java

/**
 * Created by IntelliJ IDEA.
 * User: jirka
 * Date: 11/4/11
 * Time: 7:19 PM
 * To change this template use File | Settings | File Templates.
 */
public class TestovaciB implements ExecutableClass {
    public void execute() {
        System.out.println("Hello from TestovaciB");
    }
}

TestovaciC.java

/**
 * Created by IntelliJ IDEA.
 * User: jirka
 * Date: 11/4/11
 * Time: 8:10 PM
 * To change this template use File | Settings | File Templates.
 */
public class TestovaciC {
    public static void main(String[] args) {
        System.out.println("Hello from TestovaciC");
    }
}