Develop Reference

How to add properly UiHandler for BlurEvent in GWT?

Normally if we have some textField in GWT we can add a BlurHandler by the following code:
textField.addBlurHandler(new BlurHandler() {
#Override
public void onBlur(BlurEvent event) {
//what we need
}
});
But if we use UiBinder and our textField is annotated by #UiField and it is mentioned in our ui.xml file we can add BlurHandler by this code as well:
#UiHandler("textField")
protected void createBlurHandler(BlurEvent event) {
}
I guess I am right here because it works like this. So, the question is, can we actually define BlurHandler inside ui.xml file?
For example, it is possible to add inputMaxLength and some other attributes there, does GWT has some possibility like onChange method or are these ways that I described the only possibilities?
I would like to have something like this:
<g:TextBox ui:field="textField" onBlur="methodName" />
Is it possible?

I am pretty sure what you are asking is not possible. The problem is that you wouldn't be able to use reflection to figure out which method you want to call. However you can extends the TextBox class and use that inside your template. The extended class could have it's own properties that can be set in the template. An example is as follows where I set the default test on my own DefaultTextBox.
public class DefaultTextBox extends TextBox {
/**
* The text color used when the box is disabled and empty.
*/
private static final String TEXTBOX_DISABLED_COLOR = "#AAAAAA";
private final String defaultText;
public #UiConstructor
DefaultTextBox(final String defaultText) {
this.defaultText = defaultText;
resetDefaultText();
// Add focus and blur handlers.
addFocusHandler(new FocusHandler() {
#Override
public void onFocus(FocusEvent event) {
getElement().getStyle().clearColor();
getElement().getStyle().clearFontStyle();
if (defaultText.equals(getText())) {
setText("");
}
}
});
addBlurHandler(new BlurHandler() {
#Override
public void onBlur(BlurEvent event) {
if ("".equals(getText())) {
resetDefaultText();
}
}
});
}
public String getDefaultText() {
return defaultText;
}
#Override
public void setText(String text) {
if (text == null) {
super.setText(getDefaultText());
} else {
getElement().getStyle().clearColor();
getElement().getStyle().clearFontStyle();
super.setText(text);
}
}
public String getText() {
return super.getText();
}
/**
* This is override so that the editor framework will not get the default
* value but the actual null value when the default text is in the box.
*/
#Override
public String getValue() {
try {
return getValueOrThrow();
} catch (ParseException e) {
return null;
}
}
#Override
public void setValue(String value) {
setText(value);
}
/**
* This is overridden from the parent class because this is
* how the editor gets the value.
*/
public String getValueOrThrow() throws ParseException {
if (defaultText.equals(super.getValueOrThrow())) {
return null;
}
return super.getValueOrThrow();
}
/**
* Reset the text box to the default text.
*/
public void resetDefaultText() {
setText(defaultText);
getElement().getStyle().setColor(TEXTBOX_DISABLED_COLOR);
getElement().getStyle().setFontStyle(FontStyle.ITALIC);
}
}
Then in the template you can set properties like this.
<w:DefaultTextBox defaultText="name" ui:field="nameTextBox" />
This will also work with setters, you can set properties without having to use the #UiConstructor but in my case I wanted to make sure that there was no empty constructor for this class.

property change lister does not invoke the method propertychangeevent

Below is my code regarding property change. If I use this code,
public void propertyChange(PropertyChangeEvent evt) will be called properly.
public void setWeekDate(Date weekDate) {
firePropertyChange("weekDate", this.weekDate, this.weekDate = weekDate);
}
But if I use below code public void propertyChange(PropertyChangeEvent evt) will not be
called.
public void setWeekDate(Date weekDate) {
this.weekDate = weekDate;
firePropertyChange("weekDate", this.weekDate, weekDate);
}
could anyone tell me whats wrong with the above code?

In the second instance, you provide the same value twice. I'm guessing firePropertyChange does nothing if the value didn't actually change. Try this:
public void setWeekDate(Date weekDate) {
Date oldValue = this.weekDate;
this.weekDate = weekDate;
firePropertyChange("weekDate", oldValue, this.weekDate);
}

Wicket: Update Model on DropDownChoice Item Selection Event

I need to update a model or object immediately after select
a DropDownChoice item.
Bellow is the code that I'm working:
add(new ListView[Company]("listCompanies", listData) {
override protected def onBeforeRender() {
//
// ...
super.onBeforeRender()
}
def populateItem(item: ListItem[Company]) = {
var company = item.getModelObject()
//...
val listClients: java.util.List[Client] = clientControler.listClients
item.add(new DropDownChoice("clientSelection", listClients,new ChoiceRenderer[Client]("name")))
In the Listview with properties of Company Object,
after choose a name property of the DropDownChoice, the model
Company would be updated with the Client Name selected.
How can I achieve this?
Thanks

I think you can override onSelectionChanged. But you also need to override wantOnSelectionChangedNotifications to return true to make it work. Something like this.
DropDownChoice<Client> dropDownChoice = new DropDownChoice("clientSelection", listClients) {
#Override
protected boolean wantOnSelectionChangedNotifications() {
return true;
}
#Override
protected void onSelectionChanged(Object newSelection) {
// Do something here when selection is changed
}
};

you need to add updating behavior:
add(new DropDownChoice<Client>("clientSelection", listClients)
.add(new AjaxFormComponentUpdatingBehavior("onchange") {
private static final long serialVersionUID = 1L;
#Override
protected void onUpdate(AjaxRequestTarget target) {
// update your model here
// then you need to add model to target
target.add();
}
}));

I think you can use an AjaxEventBehavior on your DropDownChoice:
item.add(new DropDownChoice("clientSelection", listClients,new ChoiceRenderer[Client("name")).add(new AjaxEventBehavior("change") {
#Override
protected void onEvent(AjaxRequestTarget target) {
// TODO Auto-generated method stub
}
}))

GWT - Issue with property change member variable being raised while loading the data first time

I have a GWT application that loads a product when the page is loaded. I am using PropertyChangeEvent on the product object (and its sub-objects) to update the values of fields, whenever a change happens.
Of course, I do not want this PropertyChangeEvent to raise when the product is loaded for the first time. For this, I am setting the raisePropertyChange value to false, but it doesn't seem to work. Please find below the code base:
// Class ProductBaseImpl
public abstract class PropChangeImpl {
// The raise property change event, should be turned off conditionally
private boolean raisePropertyChangeEvent = true;
protected boolean getRaisePropertyChangeEvent() {
return this.raisePropertyChangeEvent;
}
protected void setRaisePropertyChangeEvent(final boolean value) {
this.raisePropertyChangeEvent = value;
}
protected void raisePropertyChangeEvent(String fieldName, Object oldValue, Object newValue) {
if (this.raisePropertyChangeEvent ) {
// --> HERE IS THE PROBLEM <--
// This IF loop must not be true when loading the product first time
System.out.println("Property change event raised!");
// the update operations go here
} else {
System.out.println("Property change event not raised!");
}
}
}
// Class ProductBaseImpl
public abstract class ProductBaseImpl extends PropChangeImpl {
private static HandlerRegistration productChangeBeginRegistration;
private static HandlerRegistration productChangeEndRegistration;
protected E instance;
protected ProductBaseImpl(final E instance) {
this.instance = instance;
// Stop updates when a new product loads
if (ProductBaseImpl.productChangeBeginRegistration == null) {
ProductBaseImpl.productChangeBeginRegistration = Core.getEventBus().addHandler(ProductChangeBeginEvent.TYPE, new ProductChangeBeginEventEventHandler() {
#Override
public void onProductChangeBegin(final ProductChangeBeginEvent event) {
ProductBaseImpl.this.raisePropertyChangeEvent(false);
}
});
}
if (ProductBaseImpl.productChangeEndRegistration == null) {
ProductBaseImpl.productChangeEndRegistration = Core.getEventBus().addHandler(ProductChangeEndEvent.TYPE, new ProductChangeEndEventtHandler() {
#Override
public void onProductChangeEnd(final ProductChangeEndEvent event) {
ProductBaseImpl.this.raisePropertyChangeEvent(true);
}
});
}
}
}
// Class ProductSubObj1
public class ProductSubObj1 extends ProductBaseImpl {
public ProductSubObj1 (final E instance) {
super(instance);
// some other operations
}
}
// similar to above, I have classes ProductSubObj1, ProductSubObj2 ...
// Class ProductProvider, that fetches the product from service to UI
public class ProductProvider {
// some properties and members
public void fetchProduct(String productId) {
// Let listeners know the product is about to change
Core.getEventBus().fireEvent(new ProductChangeBeginEvent(productId));
// Call the service to get the product in Json data
// After processing the data to be available for the UI (and scheduleDeferred)
Core.getEventBus().fireEvent(new ProductChangeEndEvent(productId));
}
}
As commented inline in the code, the control always goes within the
if (this.raiseDataChangeEvent)
block which I don't want to happen when the product is loaded for the first time.
Could you please advise what am I doing wrong?
Thanks.

Can you just do this:?
protected void raisePropertyChangeEvent(String fieldName, Object oldValue, Object newValue) {
if (this.raisePropertyChangeEvent && oldValue != null /*Or whatever your default unloaded value is*/) {
// --> HERE IS THE PROBLEM <--
// This IF loop must not be true when loading the product first time
System.out.println("Property change event raised!");
// the update operations go here
} else {
System.out.println("Property change event not raised!");
}
}

Implements an Undo/Redo in MVC

I have a Java application and I want to implement an Undo/Redo option. the value that I want to stock and that I want to be able to recover is an integer.
My Class Model implements the interface StateEditable and I have to redefine the 2 functions restoreState(Hashtable<?, ?> state) and storeState(Hashtable<Object, Object> state) but I don't know what to put on them. It will be really great if somebody can help me to do that.
These are the first lines of my Model class, the value that I want to do an undo/redo on it is value
public class Model extends Observable implements StateEditable
{
private int value = 5;
private UndoManager undoRedo = new UndoManager();
final UndoableEditListener editListener = new UndoableEditListener() {
public void undoableEditHappened(UndoableEditEvent evt) {
undoRedo.addEdit(evt.getEdit());
}
};
#Override
public void restoreState(Hashtable<?, ?> state)
{
}
#Override
public void storeState(Hashtable<Object, Object> state)
{
}
}

From looking through an example of StateEditable, it would appear that in your storeState method, you need to populate the Hashtable that is passed in. Similarly, you assign state in your restoreState from the Hashtable that is passed in. You will need to define a key for the value in the Hashtable. With that in mind, I suggest that you add
private final String KEY = "myKey";
to the top of your file, and then fill out the two methods like so:
#Override
public void restoreState(Hashtable<?, ?> state)
{
Object val = state.get(KEY);
if( val instanceof Integer ) //performs the null test for us.
{
value = val;
}
}
#Override
public void storeState(Hashtable<Object, Object> state)
{
state.put(KEY, value);
}