As a follow-up to Why are there no decent examples of CompositeCell in use within a CellTable?
I am trying to add-on JSR-303 validation support. I have followed Koma's config advice here: How to install gwt-validation with gwt-2.4.0 (Note: I'm using GWT 2.4's built-in validation, not GWT-Validation).
Again, in order to get some re-use I crafted a pair of classes, ValidatableInputCell and AbstractValidatableColumn. I got inspiration for them from:
- http://code.google.com/p/google-web-toolkit/source/browse/trunk/samples/validation/src/main/java/com/google/gwt/sample/validation/client/ValidationView.java?r=10642
- http://gwt.google.com/samples/Showcase/Showcase.html#!CwCellValidation
Let's have a look at 'em...
public class ValidatableInputCell extends AbstractInputCell<String, ValidatableInputCell.ValidationData> {
interface Template extends SafeHtmlTemplates {
@Template("<input type=\"text\" value=\"{0}\" size=\"{1}\" style=\"{2}\" tabindex=\"-1\"></input>")
SafeHtml input(String value, String width, SafeStyles color);
}
private static Template template;
/**
* The error message to be displayed as a pop-up near the field
*/
private String errorMessage;
private static final int DEFAULT_INPUT_SIZE = 15;
/**
* Specifies the width, in characters, of the <input> element contained within this cell
*/
private int inputSize = DEFAULT_INPUT_SIZE;
public ValidatableInputCell() {
super("change", "keyup");
if (template == null) {
template = GWT.create(Template.class);
}
}
public void setInputSize(int inputSize) {
this.inputSize = inputSize;
}
public void setErrorMessage(String errorMessage) {
this.errorMessage = SafeHtmlUtils.htmlEscape(errorMessage);
}
@Override
public void onBrowserEvent(Context context, Element parent, String value,
NativeEvent event, ValueUpdater<String> valueUpdater) {
super.onBrowserEvent(context, parent, value, event, valueUpdater);
// Ignore events that don't target the input.
final InputElement input = (InputElement) getInputElement(parent);
final Element target = event.getEventTarget().cast();
if (!input.isOrHasChild(target)) {
return;
}
final Object key = context.getKey();
final String eventType = event.getType();
if ("change".equals(eventType)) {
finishEditing(parent, value, key, valueUpdater);
} else if ("keyup".equals(eventType)) {
// Mark cell as containing a pending change
input.getStyle().setColor("blue");
ValidationData viewData = getViewData(key);
// Save the new value in the view data.
if (viewData == null) {
viewData = new ValidationData();
setViewData(key, viewData);
}
final String newValue = input.getValue();
viewData.setValue(newValue);
finishEditing(parent, newValue, key, valueUpdater);
// Update the value updater, which updates the field updater.
if (valueUpdater != null) {
valueUpdater.update(newValue);
}
}
}
@Override
public void render(Context context, String value, SafeHtmlBuilder sb) {
// Get the view data.
final Object key = context.getKey();
ValidationData viewData = getViewData(key);
if (viewData != null && viewData.getValue().equals(value)) {
// Clear the view data if the value is the same as the current value.
clearViewData(key);
viewData = null;
}
/*
* If viewData is null, just paint the contents black. If it is non-null,
* show the pending value and paint the contents red if they are known to
* be invalid.
*/
final String pendingValue = viewData == null ? null : viewData.getValue();
final boolean invalid = viewData == null ? false : viewData.isInvalid();
final String color = pendingValue != null ? invalid ? "red" : "blue" : "black";
final SafeStyles safeColor = SafeStylesUtils.fromTrustedString("color: " + color + ";");
sb.append(template.input(pendingValue != null ? pendingValue : value, String.valueOf(inputSize), safeColor));
}
@Override
protected void onEnterKeyDown(Context context, Element parent, String value,
NativeEvent event, ValueUpdater<String> valueUpdater) {
final Element target = event.getEventTarget().cast();
if (getInputElement(parent).isOrHasChild(target)) {
finishEditing(parent, value, context.getKey(), valueUpdater);
} else {
super.onEnterKeyDown(context, parent, value, event, valueUpdater);
}
}
@Override
protected void finishEditing(Element parent, String value, Object key,
ValueUpdater<String> valueUpdater) {
final ValidationData viewData = getViewData(key);
final String pendingValue = viewData == null ? null : viewData.getValue();
final boolean invalid = viewData == null ? false : viewData.isInvalid();
if (invalid) {
final DecoratedPopupPanel errorMessagePopup = new DecoratedPopupPanel(true);
final VerticalPanel messageContainer = new VerticalPanel();
messageContainer.setWidth("200px");
final Label messageTxt = new Label(errorMessage, true);
messageTxt.setStyleName(UiResources.INSTANCE.style().error());
messageContainer.add(messageTxt);
errorMessagePopup.setWidget(messageContainer);
// Reposition the popup relative to input field
final int left = parent.getAbsoluteRight() + 25;
final int top = parent.getAbsoluteTop();
errorMessagePopup.setPopupPositionAndShow(new PopupPanel.PositionCallback() {
@Override
public void setPosition(int offsetWidth, int offsetHeight) {
errorMessagePopup.setPopupPosition(left, top);
}
});
}
// XXX let user continue or force focus until value is valid? for now the former is implemented
super.finishEditing(parent, pendingValue, key, valueUpdater);
}
/**
* The ViewData used by {@link ValidatableInputCell}.
*/
static class ValidationData {
private boolean invalid;
private String value;
public String getValue() {
return value;
}
public boolean isInvalid() {
return invalid;
}
public void setInvalid(boolean invalid) {
this.invalid = invalid;
}
public void setValue(String value) {
this.value = value;
}
}
}
and
public abstract class AbstractValidatableColumn<T> implements HasCell<T, String> {
private ValidatableInputCell cell = new ValidatableInputCell();
private CellTable<T> table;
public AbstractValidatableColumn(int inputSize, CellTable<T> table) {
cell.setInputSize(inputSize);
this.table = table;
}
@Override
public Cell<String> getCell() {
return cell;
}
@Override
public FieldUpdater<T, String> getFieldUpdater() {
return new FieldUpdater<T, String>() {
@Override
public void update(int index, T dto, String value) {
final Set<ConstraintViolation<T>> violations = validate(dto);
final ValidationData viewData = cell.getViewData(dto);
if (!violations.isEmpty()) { // invalid
final StringBuffer errorMessage = new StringBuffer();
for (final ConstraintViolation<T> constraintViolation : violations) {
errorMessage.append(constraintViolation.getMessage());
}
viewData.setInvalid(true);
cell.setErrorMessage(errorMessage.toString());
table.redraw();
} else { // valid
viewData.setInvalid(false);
cell.setErrorMessage(null);
doUpdate(index, dto, value);
}
}
};
}
protected abstract void doUpdate(int index, T dto, String value);
protected Set<ConstraintViolation<T>> validate(T dto) {
final Validator validator = Validation.buildDefaultValidatorFactory().getValidator();
final Set<ConstraintViolation<T>> violations = validator.validate(dto);
return violations;
}
}
I use the AbstractValidatableColumn like so...
protected HasCell<ReserveOfferDTO, String> generatePriceColumn(DisplayMode currentDisplayMode) {
HasCell<ReserveOfferDTO, String> priceColumn;
if (isInEditMode(currentDisplayMode)) {
priceColumn = new AbstractValidatableColumn<ReserveOfferDTO>(5, this) {
@Override
public String getValue(ReserveOfferDTO reserveOffer) {
return obtainPriceValue(reserveOffer);
}
@Override
protected void doUpdate(int index, ReserveOfferDTO reserveOffer, String value) {
// number format exceptions should be caught and handled by event bus's handle method
final double valueAsDouble = NumberFormat.getDecimalFormat().parse(value);
final BigDecimal price = BigDecimal.valueOf(valueAsDouble);
reserveOffer.setPrice(price);
}
};
} else {
priceColumn = new Column<ReserveOfferDTO, String>(new TextCell()) {
@Override
public String getValue(ReserveOfferDTO reserveOffer) {
return obtainPriceValue(reserveOffer);
}
};
}
return priceColumn;
}
Oh! And here's the DTO with JSR-303 annotations...
public class ReserveOfferDTO extends DateComparable implements Serializable {
private static final long serialVersionUID = 1L;
@NotNull @Digits(integer=6, fraction=2)
private BigDecimal price;
@NotNull @Digits(integer=6, fraction=2)
private BigDecimal fixedMW;
private String dispatchStatus;
private String resourceName;
private String dateTime;
private String marketType;
private String productType;
...
}
Dropping a breakpoint in onBrowserEvent I would expect to have the validation trigger on each key stroke and/or after cell loses focus. It never gets invoked. I can enter whatever I like in the cell. Any clues as to an approach to fix?
My early thoughts... a) AbstractValidatableColumn#getFieldUpdater is never getting invoked and b) the logic in either ValidatableInputCell#onBrowserEvent or ValidatableInputCell#render needs an overhaul.
Ultimately, I'd like to see a popup appearing next to each cell that violates a constraint, and of course see that the appropriate coloring is applied.
UiResources.INSTANCE.style().error(), as this won't compile without your own UiResources class. TheDateComparablesuperclass probably ought to go too, andgeneratePriceColumncould probably use some additional simplification, forisInEditModeand theDisplayModeclass. – Dolores