| Код |
import java.awt.*;
import java.awt.event.*;
import java.io.File;
import java.io.FileOutputStream;
import java.io.PrintWriter;
import java.io.IOException;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
import java.util.Date;
/**
* Program that lets you run a short segment of Java code.
*
* @author Shawn Silverman
*/
public class JavaStatement extends Frame implements ActionListener {
/**
* Main entry point.
*/
public static void main(String[] args) {
// Create the frame and set it to close on exit
Frame f = new JavaStatement();
f.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
Window w = e.getWindow();
w.hide();
w.dispose();
System.exit(0);
}
});
f.pack();
f.show();
}
/** The compiler object. */
private com.sun.tools.javac.Main javac = new com.sun.tools.javac.Main();
private TextArea text;
private Button runBtn;
/**
* Create a new JavaStatement window.
*/
public JavaStatement() {
super("Java Statement");
// Create the components
text = new TextArea(5, 45);
text.setFont(new Font("Monospaced", Font.PLAIN, 12));
runBtn = new Button("Run!");
runBtn.addActionListener(this);
// Lay them out
this.add(text, BorderLayout.CENTER);
Panel p = new Panel();
p.add(runBtn);
this.add(p, BorderLayout.SOUTH);
this.setBackground(SystemColor.control);
}
/**
* Shows a message to the user.
*
* @param msg the message
*/
private void showMsg(String msg) {
System.err.println(msg);
}
/**
* Compiles and runs the short code segment.
*
* @throws IOException if there was an error creating the source file.
*/
private void doRun() throws IOException {
// Create a temp. file
File file = File.createTempFile("jav", ".java",
new File(System.getProperty("user.dir")));
// Set the file to be deleted on exit
file.deleteOnExit();
// Get the file name and extract a class name from it
String filename = file.getName();
String classname = filename.substring(0, filename.length()-5);
// Output the source
PrintWriter out = new PrintWriter(new FileOutputStream(file));
out.println("/**");
out.println(" * Source created on " + new Date());
out.println(" */");
out.println("public class " + classname + " {");
out.println(" public static void main(String[] args) throws Exception {");
// Your short code segment
out.print(" "); out.println(text.getText());
out.println(" }");
out.println("}");
// Flush and close the stream
out.flush();
out.close();
// Compile
String[] args = new String[] {
"-d", System.getProperty("user.dir"),
filename
};
int status = javac.compile(args);
// Run
switch (status) {
case 0: // OK
// Make the class file temporary as well
new File(file.getParent(), classname + ".class").deleteOnExit();
try {
// Try to access the class and run its main method
Class clazz = Class.forName(classname);
Method main = clazz.getMethod("main", new Class[] { String[].class });
main.invoke(null, new Object[] { new String[0] });
} catch (InvocationTargetException ex) {
// Exception in the main method that we just tried to run
showMsg("Exception in main: " + ex.getTargetException());
ex.getTargetException().printStackTrace();
} catch (Exception ex) {
showMsg(ex.toString());
}
break;
case 1: showMsg("Compile status: ERROR"); break;
case 2: showMsg("Compile status: CMDERR"); break;
case 3: showMsg("Compile status: SYSERR"); break;
case 4: showMsg("Compile status: ABNORMAL"); break;
default:
showMsg("Compile status: Unknown exit status");
}
}
/**
* Listens to actions from the run button.
*/
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
if (runBtn == source) {
// Disable the run button while we're running
runBtn.setEnabled(false);
try {
doRun();
} catch (IOException ex) {
ex.printStackTrace();
}
runBtn.setEnabled(true);
}
}
}
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