Algorithm selection error handling

src/ui/view/AlgorithmMenu.java

@@ -14,9 +14,11 @@ import javax.swing.JFileChooser;
 import javax.swing.JFrame;
 import javax.swing.JMenu;
 import javax.swing.JMenuItem;
+import javax.swing.JOptionPane;
 import javax.tools.JavaCompiler;
 import javax.tools.ToolProvider;
 
+import api.CpsAlgorithm;
 import ui.controller.Control;
 import ui.model.Model;
 
@@ -129,7 +131,8 @@ public class AlgorithmMenu extends JMenu {
 	}
 
 	public void setAlgorithm(File file, String name) {
-		boolean missinConsole = false;
+		boolean missingCompiler = false;
+		boolean instantiationError = false;
 		try {
 			BufferedReader br = new BufferedReader(new FileReader(file.getPath()));
 			String line = br.readLine();
@@ -155,7 +158,7 @@ public class AlgorithmMenu extends JMenu {
 			JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
 
 			if (ToolProvider.getSystemJavaCompiler() == null) {
-				missinConsole = true;
+				missingCompiler = true;
 			}
 
 			compiler.run(null, null, null, file.getPath());
@@ -163,6 +166,7 @@ public class AlgorithmMenu extends JMenu {
 			// Load and instantiate compiled class.
 			URLClassLoader classLoader = URLClassLoader.newInstance(new URL[] { root.toURI().toURL() });
 
+			instantiationError = true;
 			Class<?> cls;
 			if (packageName.isEmpty()) {
 				cls = Class.forName(name, true, classLoader);
@@ -171,14 +175,23 @@ public class AlgorithmMenu extends JMenu {
 			}
 
 			Object t = cls.newInstance();
-
-			controller.setAlgorithm(t);
-
+			if (t instanceof CpsAlgorithm) {
+				controller.setAlgorithm(t);
+			} else {
+				JOptionPane.showMessageDialog(null, "Class does not Implement CpsAlgorithm!", "Error!",
+						JOptionPane.ERROR_MESSAGE);
+				noneItem.doClick();
+			}
 		} catch (Exception e) {
-			if (missinConsole) {
-				controller.addTextToConsole("missing Compiiler! Please install JDK");
+			if (missingCompiler) {
+				JOptionPane.showMessageDialog(null, "Missing Compiiler! Please install JDK!", "Error!",
+						JOptionPane.ERROR_MESSAGE);
+			} else if (instantiationError) {
+				JOptionPane.showMessageDialog(null, "Class does not Implement CpsAlgorithm!", "Error!",
+						JOptionPane.ERROR_MESSAGE);
+				noneItem.doClick();
 			} else {
-				controller.addTextToConsole(e.toString());
+				JOptionPane.showMessageDialog(null, e.toString(), "Error!", JOptionPane.ERROR_MESSAGE);
 			}
 		}
 	}