Added new design pattern.

Implementation for the Model-View-Presenter pattern is now available.

model-view-presenter/src/main/java/com/iluwatar/FileSelectorPresenter.java

@@ -0,0 +1,74 @@
+/**
+ * Every instance of this class represents the Presenter component
+ * in the Model-View-Presenter architectural pattern.
+ * 
+ * It is responsible for reacting to the user's actions and update the View component.
+ */
+public class FileSelectorPresenter {
+	
+	/**
+	 * The View component that the presenter interacts with.
+	 */
+	private FileSelectorView view;
+	
+	/**
+	 * The Model component that the presenter interacts with.
+	 */
+	private FileLoader loader;
+	
+	/**
+	 * Constructor
+	 * 
+	 * @param view The view component that the presenter will interact with.
+	 */
+	public FileSelectorPresenter(FileSelectorView view) {
+		this.view = view;
+	}
+	
+	/**
+	 * Sets the FileLoader object, to the value given as parameter.
+	 * 
+	 * @param loader The new FileLoader object(the Model component).
+	 */
+	public void setLoader(FileLoader loader) {
+		this.loader = loader;
+	}
+	
+	/**
+	 * Starts the presenter.
+	 */
+	public void start() {
+		view.setPresenter(this);
+		view.open();
+	}
+	
+	/**
+	 * An "event" that fires when the name of the file to be loaded changes.
+	 */
+	public void fileNameChanged() {
+		loader.setFileName(view.getFileName());
+	}
+	
+	public void confirmed() {
+		if(loader.getFileName() == null || loader.getFileName().equals("")) {
+			view.showMessage("Please give the name of the file first!");
+			return;
+		}
+		
+		if(loader.fileExists()) {
+			String data = loader.loadData();
+			view.displayData(data);
+		} 
+		
+		else {
+			view.showMessage("The file specified does not exist.");
+		}
+	}
+	
+	/**
+	 * Cancels the file loading process.
+	 */
+	public void cancelled() {
+		view.close();
+	}	
+}