gwt - model objects agnostic of presenters

architecture-examples/gwt/src/com/todo/client/ToDoCell.java

@@ -11,10 +11,14 @@ import com.google.gwt.dom.client.EventTarget;
 import com.google.gwt.dom.client.InputElement;
 import com.google.gwt.dom.client.NativeEvent;
 import com.google.gwt.event.dom.client.KeyCodes;
+import com.google.gwt.event.shared.EventBus;
 import com.google.gwt.safehtml.client.SafeHtmlTemplates;
 import com.google.gwt.safehtml.shared.SafeHtml;
 import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
 import com.google.gwt.safehtml.shared.SafeHtmlUtils;
+import com.todo.client.events.ToDoEvent;
+import com.todo.client.events.ToDoRemovedEvent;
+import com.todo.client.events.ToDoUpdatedEvent;
 
 /**
  * A cell that renders {@link ToDoItem} instances. This cell is rendered in both view and edit modes
@@ -69,8 +73,11 @@ public class ToDoCell extends AbstractCell<ToDoItem> {
 	 */
 	private boolean beginningEdit = false;
 
+	private EventBus eventBus;
+
 	public ToDoCell() {
 		super("click", "keyup", "blur", "dblclick");
+		eventBus = ToDoEvent.getGlobalEventBus();
 	}
 
 	@Override
@@ -81,8 +88,8 @@ public class ToDoCell extends AbstractCell<ToDoItem> {
 			sb.append(rendered);
 		} else {
 			SafeHtml rendered =
-					templates.view(value.isDone() ? templates.inputChecked() : templates.inputClear(),
-							SafeHtmlUtils.fromString(value.getTitle()), value.isDone() ? "listItem view completed"
+					templates.view(value.isCompleted() ? templates.inputChecked() : templates.inputClear(),
+							SafeHtmlUtils.fromString(value.getTitle()), value.isCompleted() ? "listItem view completed"
 									: "listItem view",
 							// NOTE: The addition of a timestamp here is a bit of a HACK! The problem
 							// is that the CellList uses a HasDataPresenter for rendering. This class
@@ -152,9 +159,10 @@ public class ToDoCell extends AbstractCell<ToDoItem> {
 				// check whether the checkbox was clicked
 				if (tagName.equals("INPUT")) {
 
-					// if so, synchronise the model state
+					// if so, synchronize the model state
 					InputElement input = clickedElement.cast();
-					value.setDone(input.isChecked());
+					value.setCompleted(input.isChecked());
+					eventBus.fireEvent(new ToDoUpdatedEvent(value));
 
 					// update the 'row' style
 					if (input.isChecked()) {
@@ -165,7 +173,7 @@ public class ToDoCell extends AbstractCell<ToDoItem> {
 
 				} else if (tagName.equals("BUTTON")) {
 					// if the delete anchor was clicked - delete the item
-					value.delete();
+					eventBus.fireEvent(new ToDoRemovedEvent(value));
 				}
 			}
 		}
@@ -178,6 +186,7 @@ public class ToDoCell extends AbstractCell<ToDoItem> {
 	private void commitEdit(Element parent, ToDoItem value) {
 		InputElement input = getInputElement(parent);
 		value.setTitle(input.getValue());
+		eventBus.fireEvent(new ToDoUpdatedEvent(value));
 	}
 
 	/**

architecture-examples/gwt/src/com/todo/client/ToDoItem.java

@@ -4,39 +4,30 @@ package com.todo.client;
  * An individual ToDo item.
  *
  * @author ceberhardt
+ * @author dprotti
  *
  */
 public class ToDoItem {
 
-	private final ToDoPresenter presenter;
-
 	private String title;
 
-	private boolean done;
+	private boolean completed;
 
-	public ToDoItem(String text, ToDoPresenter presenter) {
-		this.title = text;
-		this.done = false;
-		this.presenter = presenter;
+	public ToDoItem(String title) {
+		this(title, false);
 	}
 
-	public ToDoItem(String title, boolean done, ToDoPresenter presenter) {
+	public ToDoItem(String title, boolean completed) {
 		this.title = title;
-		this.done = done;
-		this.presenter = presenter;
-	}
-
-	public boolean isDone() {
-		return done;
+		this.completed = completed;
 	}
 
-	public void setDone(boolean done) {
-		this.done = done;
-		presenter.itemStateChanged(this);
+	public boolean isCompleted() {
+		return completed;
 	}
 
-	public void delete() {
-		presenter.deleteTask(this);
+	public void setCompleted(boolean completed) {
+		this.completed = completed;
 	}
 
 	public String getTitle() {
@@ -44,13 +35,7 @@ public class ToDoItem {
 	}
 
 	public void setTitle(String title) {
-		setTitle(title, true);
-	}
-
-	public void setTitle(String title, boolean notify) {
 		this.title = title;
-		if (notify) {
-			presenter.itemStateChanged(this);
-		}
 	}
+
 }

architecture-examples/gwt/src/com/todo/client/ToDoPresenter.java

@@ -6,6 +6,7 @@ import java.util.List;
 
 import com.google.gwt.event.logical.shared.ValueChangeEvent;
 import com.google.gwt.event.logical.shared.ValueChangeHandler;
+import com.google.gwt.event.shared.EventBus;
 import com.google.gwt.json.client.JSONArray;
 import com.google.gwt.json.client.JSONBoolean;
 import com.google.gwt.json.client.JSONObject;
@@ -15,12 +16,18 @@ import com.google.gwt.storage.client.Storage;
 import com.google.gwt.user.client.History;
 import com.google.gwt.view.client.AbstractDataProvider;
 import com.google.gwt.view.client.ListDataProvider;
+import com.todo.client.ToDoItem;
+import com.todo.client.ToDoRouting;
+import com.todo.client.events.ToDoEvent;
+import com.todo.client.events.ToDoRemovedEvent;
+import com.todo.client.events.ToDoUpdatedEvent;
 
 /**
  * The presenter for the ToDo application. This class is responsible for the lifecycle of the
  * {@link ToDoItem} instances.
  *
  * @author ceberhardt
+ * @author dprotti
  *
  */
 public class ToDoPresenter {
@@ -111,7 +118,7 @@ public class ToDoPresenter {
 	
 	private ToDoRouting routing = ToDoRouting.ALL;
 	
-	private boolean suppressStateChanged = false;
+	private EventBus eventBus;
 
 	public ToDoPresenter(View view) {
 		this.view = view;
@@ -127,6 +134,25 @@ public class ToDoPresenter {
 		
 		updateTaskStatistics();
 		setupHistoryHandler();
+		eventBus = ToDoEvent.getGlobalEventBus();
+		// listen to edits on individual items
+		eventBus.addHandler(ToDoUpdatedEvent.TYPE, new ToDoUpdatedEvent.Handler() {
+
+			@Override
+			public void onEvent(ToDoUpdatedEvent event) {
+				itemStateChanged(event.getToDo());
+			}
+
+		});
+		// listen to removals
+		eventBus.addHandler(ToDoRemovedEvent.TYPE, new ToDoRemovedEvent.Handler() {
+
+			@Override
+			public void onEvent(ToDoRemovedEvent event) {
+				deleteTask(event.getToDo());
+			}
+
+		});
 	}
 
 	/**
@@ -176,7 +202,7 @@ public class ToDoPresenter {
 
 		int completeTask = 0;
 		for (ToDoItem task : todos) {
-			if (task.isDone()) {
+			if (task.isCompleted()) {
 				completeTask++;
 			}
 		}
@@ -197,12 +223,7 @@ public class ToDoPresenter {
 	 */
 	protected void itemStateChanged(ToDoItem toDoItem) {
 
-		if (suppressStateChanged) {
-			return;
-		}
-
-		boolean notify = false;
-		toDoItem.setTitle(toDoItem.getTitle().trim(), notify);
+		toDoItem.setTitle(toDoItem.getTitle().trim());
 
 		if (toDoItem.getTitle().isEmpty()) {
 			todos.remove(toDoItem);
@@ -225,12 +246,9 @@ public class ToDoPresenter {
 	 */
 	private void markAllCompleted(boolean completed) {
 
-		// update the completed state of each item
-		suppressStateChanged = true;
 		for (ToDoItem task : todos) {
-			task.setDone(completed);
+			task.setCompleted(completed);
 		}
-		suppressStateChanged = false;
 
 		taskStateChanged();
 	}
@@ -245,7 +263,7 @@ public class ToDoPresenter {
 		if (taskTitle.equals(""))
 			return;
 
-		ToDoItem toDoItem = new ToDoItem(taskTitle, this);
+		ToDoItem toDoItem = new ToDoItem(taskTitle);
 		view.clearTaskText();
 		todos.add(toDoItem);
 		
@@ -259,7 +277,7 @@ public class ToDoPresenter {
 		Iterator<ToDoItem> iterator = todos.iterator();
 		while (iterator.hasNext()) {
 			ToDoItem item = iterator.next();
-			if (item.isDone()) {
+			if (item.isCompleted()) {
 				iterator.remove();
 			}
 		}
@@ -280,7 +298,7 @@ public class ToDoPresenter {
 				ToDoItem toDoItem = todos.get(i);
 				JSONObject jsonObject = new JSONObject();
 				jsonObject.put("task", new JSONString(toDoItem.getTitle()));
-				jsonObject.put("complete", JSONBoolean.getInstance(toDoItem.isDone()));
+				jsonObject.put("complete", JSONBoolean.getInstance(toDoItem.isCompleted()));
 				todoItems.set(i, jsonObject);
 			}
 
@@ -304,7 +322,7 @@ public class ToDoPresenter {
 					String task = jsonObject.get("task").isString().stringValue();
 					boolean completed = jsonObject.get("complete").isBoolean().booleanValue();
 					// add a new item to our list
-					todos.add(new ToDoItem(task, completed, this));
+					todos.add(new ToDoItem(task, completed));
 				}
 			} catch (Exception e) {
 

architecture-examples/gwt/src/com/todo/client/ToDoRouting.java

@@ -40,7 +40,7 @@ public enum ToDoRouting {
 	private static class MatchActive implements Matcher {
 		@Override
 		public boolean matches(ToDoItem item) {
-			return !item.isDone();
+			return !item.isCompleted();
 		}
 	}
 
@@ -50,7 +50,7 @@ public enum ToDoRouting {
 	private static class MatchCompleted implements Matcher {
 		@Override
 		public boolean matches(ToDoItem item) {
-			return item.isDone();
+			return item.isCompleted();
 		}
 	}
 

architecture-examples/gwt/src/com/todo/client/events/ToDoEvent.java

+package com.todo.client.events;
+
+import com.google.gwt.event.shared.EventBus;
+import com.google.gwt.event.shared.EventHandler;
+import com.google.gwt.event.shared.GwtEvent;
+import com.google.gwt.event.shared.SimpleEventBus;
+import com.todo.client.ToDoItem;
+
+public abstract class ToDoEvent<H extends EventHandler> extends GwtEvent<H> {
+
+	private final ToDoItem toDo;
+
+	public ToDoEvent(ToDoItem toDo) {
+		this.toDo = toDo;
+	}
+
+	public ToDoItem getToDo() {
+		return toDo;
+	}
+
+	/* This acts as a global event bus factory */
+
+	private static EventBus eventBus = new SimpleEventBus();
+
+	public static EventBus getGlobalEventBus() {
+		return eventBus;
+	}
+
+}

architecture-examples/gwt/src/com/todo/client/events/ToDoRemovedEvent.java

+package com.todo.client.events;
+
+import com.google.gwt.event.shared.EventHandler;
+import com.todo.client.ToDoItem;
+
+public class ToDoRemovedEvent extends ToDoEvent<ToDoRemovedEvent.Handler> {
+
+	public static final Type<ToDoRemovedEvent.Handler> TYPE = new Type<ToDoRemovedEvent.Handler>();
+
+	public static interface Handler extends EventHandler {
+
+		void onEvent(ToDoRemovedEvent event);
+	}
+
+	public ToDoRemovedEvent(ToDoItem toDo) {
+		super(toDo);
+	}
+
+	@Override
+	public Type<ToDoRemovedEvent.Handler> getAssociatedType() {
+		return TYPE;
+	}
+
+	@Override
+	protected void dispatch(ToDoRemovedEvent.Handler handler) {
+		handler.onEvent(this);
+	}
+}
\ No newline at end of file

architecture-examples/gwt/src/com/todo/client/events/ToDoUpdatedEvent.java

+package com.todo.client.events;
+
+import com.google.gwt.event.shared.EventHandler;
+import com.todo.client.ToDoItem;
+
+public class ToDoUpdatedEvent extends ToDoEvent<ToDoUpdatedEvent.Handler> {
+
+	public static final Type<ToDoUpdatedEvent.Handler> TYPE = new Type<ToDoUpdatedEvent.Handler>();
+
+	public static interface Handler extends EventHandler {
+
+		void onEvent(ToDoUpdatedEvent event);
+	}
+
+	public ToDoUpdatedEvent(ToDoItem toDo) {
+		super(toDo);
+	}
+
+	@Override
+	public Type<ToDoUpdatedEvent.Handler> getAssociatedType() {
+		return TYPE;
+	}
+
+	@Override
+	protected void dispatch(ToDoUpdatedEvent.Handler handler) {
+		handler.onEvent(this);
+	}
+}
\ No newline at end of file