How to add ValueChangeHandler to the customize DateBox? - gwt

Question

I want to add the functionality of value change handler to my customize class that extends the DateBox. I had already added the key handler but I also want to implement the value change handler to the same class.
I want my DateBox to work properly when I take input from DatePicker or Keyboard.
Any other suggestion will also be helpful.
public class ValidationDateBoxInternal extends DateBox implements KeyUpHandler{
private List<String> regexList;
public ValidationDateBoxInternal(){
super();
this.getTextBox().addKeyUpHandler(this);
regexList = new ArrayList<String>();
}
public void setAsNotEmpty() {
regexList.add(DateValidation.isNotEmpty);
isValid();
}
public void setAsValidDate(){
regexList.add(DateValidation.isValidDate);
isValid();
}
public void onKeyUp(KeyUpEvent event) {
isValid();
}
public void setText(String text) {
super.getTextBox().setText(text);
isValid();
}
public void clearRegexList() {
regexList.clear();
}
public String getText() {
if (regexList.size() == 0) {
return super.getTextBox().getText();
}
if (isValid()) {
for (String regex: regexList) {
if (regex.equals(DateValidation.isValidDate)) {
return super.getTextBox().getText().toLowerCase().trim();
}
}
return super.getTextBox().getText().trim();
}
else {
return null;
}
}
public boolean isValid() {
for (String regex: regexList) {
if (!DateValidation.isValid(super.getTextBox().getText(), regex)) {
this.addStyleName("invalid");
return false;
}
}
this.removeStyleName("invalid");
return true;
}
}

Answer 1

Your class extends DateBox, which implements the HasValueChangeHandlers interface. So you can call:
DateBox.addValueChangeHandler(ValueChangeHandler<java.util.Date> handler)
For example:
public class MyDateBox extends DateBox implements ValueChangeHandler<Date> {
void foo() {
addValueChangeHandler(this);
}
void onValueChange(ValueChangeEvent<Date> event) {
// validate the value of the DateBox
}
}