Develop Reference

TableViewer does not update the default value of a cell

I have a UI bug in a legacy code in our Java project. We display a table, with three columns (HumanReadable, name and value) in a window. In that window, users can click on each cell and update the values. Before that, user clicks the "add" button to add a new row (three new cells). Each cell has a default value, until the user decides to update the value. Now, when the users decides to update the value of the cell, he clicks on the cell and types in the value. The bug is that, once done editing, it keeps the default value in the UI. In the backend, the value has changed (if you click the cell again, it will go into editing mode and show you the value).
I uploaded a short GIF that shows the issue and can be found here.
In that GIF you can see that I updated the default value of the first column to be test. Then I click some other place (to exit the edit mode) and it showed the default value instead of test in the first column.
The method that creates the table:
private void createTable(final Composite parent) {
final Table varTable = new Table(parent, SWT.MULTI);
varTable.setHeaderVisible(true);
varTable.setLinesVisible(true);
GridDataFactory.fillDefaults().align(SWT.FILL, SWT.FILL).grab(true, true).applyTo(varTable);
varTableViewer = new TableViewer(varTable);
final DataBindingContext bindingContext = new DataBindingContext();
final TableViewerColumn col1 = GuiUtils.createTableColumn(varTableViewer, "Human Readable");
col1.setEditingSupport(new StringEditingSupport(varTableViewer, bindingContext, dataProperty));
col1.getColumn().setWidth(120);
final TableViewerColumn col2 = GuiUtils.createTableColumn(varTableViewer, "Name");
col2.getColumn().setWidth(120);
col2.setEditingSupport(new StringEditingSupport(varTableViewer, bindingContext, nameProperty));
final TableViewerColumn col3 = GuiUtils.createTableColumn(varTableViewer, "Value");
col3.setEditingSupport(new StringEditingSupport(varTableViewer, bindingContext, valueProperty));
KeyBoardNavigationSupport.createSupport(varTableViewer);
input = new WritableList(globalVars, FlowVar.class);
ViewerSupport.bind(varTableViewer, input, BeanProperties.values(new String[] { dataProperty, nameProperty, valueProperty }));
}
The StringEditingSupport class:
public class StringEditingSupport extends ObservableValueEditingSupport {
private class CellEditorPrintValidatorErrors extends TextCellEditor {
public CellEditorPrintValidatorErrors(Composite control) {
super(control);
}
#Override
protected void focusLost(){
if(this.getErrorMessage() != null) {
MessageDialog.openError(this.getControl().getShell(), "Invalid input", this.getErrorMessage());
}
}
}
private final CellEditor cellEditor;
String propertyName;
public StringEditingSupport(final ColumnViewer viewer, final DataBindingContext dbc, final String propertyName) {
super(viewer, dbc);
cellEditor = new TextCellEditor((Composite) viewer.getControl());
this.propertyName = propertyName;
}
public StringEditingSupport(final ColumnViewer viewer, final DataBindingContext dbc, final String propertyName, final ICellEditorValidator validator) {
super(viewer, dbc);
cellEditor = new CellEditorPrintValidatorErrors((Composite) viewer.getControl());
cellEditor.setValidator(validator);
this.propertyName = propertyName;
}
#Override
protected IObservableValue doCreateCellEditorObservable(final CellEditor cellEditor) {
return SWTObservables.observeText(cellEditor.getControl(), SWT.Modify);
}
#Override
protected IObservableValue doCreateElementObservable(final Object element, final ViewerCell cell) {
return BeansObservables.observeValue(element, propertyName);
}
#Override
protected CellEditor getCellEditor(final Object element) {
return cellEditor;
}
public String getErrorMessage(){
return cellEditor.getErrorMessage();
}
}
I believe it has something to do with the StringEditingSupport class. This class allows to edit the value in each cell of table. But I couldn't figure out a way to "update" the value shown in the GUI. As I understand input (of type WritableList) contains all the information. Here is the add button listener method:
private class AddButtonSelectionListener extends SelectionAdapter {
#Override
public void widgetSelected(final SelectionEvent e) {
String name = nameProperty;
String meaning = dataProperty;
final List<String> names = new ArrayList<String>();
final List<String> meanings = new ArrayList<String>();
for (final Object var : input) {
names.add(((FlowVar) var).getName());
meanings.add(((FlowVar) var).getData());
}
int index = 0;
while (names.contains(name)) {
name = nameProperty + ++index;
}
index = 0;
while (meanings.contains(meaning)) {
meaning = dataProperty + ++index;
}
input.add(new FlowVar(name, valueProperty, meaning));
}
}
So, as I understand, I need to somehow bind the input to the UI (the content of each cell). I did try many attempts like trying to set a listener to the whole table (varTableViewer.addSelectionChangedListener) but none of them worked. Is it possible to suggest a way to solve this kind of issue?
If anything is missing, please let me know and I'll add it.

Adding a note to InputDialog

I am working on eclipse JFace GUI stuff.
I am reading some input from the user and able to validate using the validator as below.
// creating input prompt
InputDialog inputDialog = new InputDialog(parentShell, dialogTitle, dialogMessage, initialValue, validator);
// Validator
IInputValidator validator = new IInputValidator()
{
#Override
public String isValid(String newName)
{
if (newName.isBlank())
{
return "Warning: Input is empty";
}
return null;
}
};
What I want to implement is to add a note to the user which is not related to validation.
Basically the note is about describing what happens if the button OK is pressed (As shown in image).
Any help/idea will be much appreciated.

You would have to create a new dialog class extending InputDialog to do this overriding createDialog to add extra controls. Something like:
public class InputDialogWithNote extends InputDialog
{
private Label noteLabel;
public InputDialogWithNote(final Shell parentShell, final String dialogTitle, final String dialogMessage, final String initialValue, final IInputValidator validator)
{
super(parentShell, dialogTitle, dialogMessage, initialValue, validator);
}
#Override
protected Control createDialogArea(final Composite parent)
{
Composite body = (Composite)super.createDialogArea(parent);
noteLabel = new Label(body, SWT.LEAD);
noteLabel.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
return body;
}
}
You will have to arrange some way to set the noteLabel field.

Comparing a String to an Object's toString() method dynamically

I'm reading from a text file, like so:
while ((line = br.readLine()) != null) {
String[] a = line.split("\\: ");
key = a[0];
action = a[1];
gameKeys.add(key, action);
}
where the file would be something like
SPACE: FIRE_ACTION
E: USE_ACTION
This part works, key and action are both what I want.
gameKeys is a Map declared like so:
private static Map<Keyboard.Key, Action> gameKeys = new HashMap<>();
Keyboard.Key has fields such as SPACE, A, RETURN, etc.
Action is an interface, that holds other actions; those actions have a toString() method that returns the action, e.g. new FireAction.toString() returns FIRE_ACTION.
Example of an Action:
public class FireAction implements Action {
#Override
public void execute() {
System.out.println("Fire key pressed!");
}
#Override
public String toString() {
return "FIRE_ACTION";
}
}
So, I'm trying to turn the file's components into objects, like if key was "SPACE" and action was "FIRE_ACTION", then, after the add method is performed, gameKeys would have <Keyboard.Key.SPACE, new FireAction()>
Is there anyway I can do this?

You could try this:
Save your Action classes in a Map<String, Class<? extends Action>>
Read the Key -> Action bindings from the file
Resolve the string action to an actual Action object via the map
Example:
public class Main {
private static final Map<Keyboard.Key, Action> gameKeys = new HashMap<>();
private static final Map<String, Class<? extends Action>> actions = new HashMap<>();
static {
actions.put(FireAction.NAME, FireAction.class);
actions.put(WalkAction.NAME, WalkAction.class);
}
public static void main(String[] args) {
// read from file etc.
try {
// e.g. found SPACE : FIRE_ACTION
gameKeys.put(Keyboard.Key.SPACE, actions.get("FIRE_ACTION").newInstance());
// e.g. found A : WALK_ACTION
gameKeys.put(Keyboard.Key.A, actions.get("WALK_ACTION").newInstance());
} catch (IllegalAccessException | InstantiationException ex) {
ex.printStackTrace();
}
}
}
public class FireAction implements Action {
public static final String NAME = "FIRE_ACTION";
#Override
public void execute() {
System.out.println("Fire key pressed!");
}
#Override
public String toString() {
return NAME;
}
}

Sure
Object keyObj = key, actionObj;
if (key.equals("SPACE")) keyObj = Keyboard.Key.SPACE;
if (action.equals("FIRE_ACTION")) actionObj = new FireAction());
You can use a Map<String, ...> as an alternative to using 'if's if you have a lot of cases

You can't achieve what you have asked directly - because then Java would have to create ALL the classes it can create(some have non-default constructors or even private), and call their toString() method (which may have side-effects in general case).
So anyway you'll have to create registry with all actions(preferrable way), or you can try to use reflection to create Actions in runtime.

how do I create a textfield which supports numbers only in vaadin

I am using a Vaadin text field and I want to restrict it to support numbers only in it. I tried to override setValue() and return without calling super. setValue() if text is not a number. But it doesn't seems to be working. How can I correct this?
I am using Vaadin 7. And I think it doesn't support NumberField as well.

If I understand you question correct, you want to have a field that ignores all inputs that are not a number and not only mark the field as invalid. Vaadins architecture is designed that every field in the browser has its representation on the server. In my opinion the cleanest way to achieve this would be to have a browser field, that permits input of letters and other wrong characters. I couldn't find such a field in Vaadin 7. There seems to be an add-on for vaadin 6 called Number Field for that, but I didn't test it.
You have multiple options:
Port this add-on to vaadin 7 or ask the author to do it
Write your own field. Maybe extending VTextField and TextFieldConnector
Do everything on the server side and accept the delays and the traffic (IMHO ugly)
Since I think option 3 is not the way to go, I probably shouldn't show this code, but it's the quickest way to implement this.
public class IntegerField extends TextField implements TextChangeListener {
String lastValue;
public IntegerField() {
setImmediate(true);
setTextChangeEventMode(TextChangeEventMode.EAGER);
addTextChangeListener(this);
}
#Override
public void textChange(TextChangeEvent event) {
String text = event.getText();
try {
new Integer(text);
lastValue = text;
} catch (NumberFormatException e) {
setValue(lastValue);
}
}
}

Vaadin 7 allows to extend their built in widgets (if you want to have more knowledge on this I really recommend this post) here is a solution which uses that mechanism.
It is composed of two classes:
Connector and the Extension
The Extension
package com.infosystem.widgets.vaadin;
import com.vaadin.server.AbstractClientConnector;
import com.vaadin.server.AbstractExtension;
import com.vaadin.ui.TextField;
public class NumberField extends AbstractExtension {
public static void extend(TextField field) {
new NumberField().extend((AbstractClientConnector) field);
}
}
Connector:
package com.infosystem.widgets.vaadin.client.numberField;
import com.google.gwt.event.dom.client.KeyCodes;
import com.google.gwt.event.dom.client.KeyPressEvent;
import com.google.gwt.event.dom.client.KeyPressHandler;
import com.infosystem.widgets.vaadin.NumberField;
import com.vaadin.client.ComponentConnector;
import com.vaadin.client.ServerConnector;
import com.vaadin.client.extensions.AbstractExtensionConnector;
import com.vaadin.client.ui.VTextField;
import com.vaadin.shared.ui.Connect;
#Connect(NumberField.class)
public class NumberFieldConnector extends AbstractExtensionConnector {
private static final long serialVersionUID = -737765038361894693L;
private VTextField textField;
private KeyPressHandler keyPressHandler = new KeyPressHandler() {
#Override
public void onKeyPress(KeyPressEvent event) {
if (textField.isReadOnly() || !textField.isEnabled()) {
return;
}
int keyCode = event.getNativeEvent().getKeyCode();
switch (keyCode) {
case KeyCodes.KEY_LEFT:
case KeyCodes.KEY_RIGHT:
case KeyCodes.KEY_BACKSPACE:
case KeyCodes.KEY_DELETE:
case KeyCodes.KEY_TAB:
case KeyCodes.KEY_UP:
case KeyCodes.KEY_DOWN:
case KeyCodes.KEY_SHIFT:
return;
}
if (!isValueValid(event)) {
textField.cancelKey();
}
}
};
#Override
protected void extend(ServerConnector target) {
textField = (VTextField) ((ComponentConnector) target).getWidget();
textField.addKeyPressHandler(keyPressHandler);
}
private boolean isValueValid(KeyPressEvent event) {
String newText = getFieldValueAsItWouldBeAfterKeyPress(event.getCharCode());
try {
parseValue(newText);
return true;
} catch (Exception e) {
return false;
}
}
protected long parseValue(String value) {
return Long.valueOf(value);
}
private String getFieldValueAsItWouldBeAfterKeyPress(char charCode) {
int index = textField.getCursorPos();
String previousText = textField.getText();
StringBuffer buffer = new StringBuffer();
buffer.append(previousText.substring(0, index));
buffer.append(charCode);
if (textField.getSelectionLength() > 0) {
buffer.append(previousText.substring(index + textField.getSelectionLength(),
previousText.length()));
} else {
buffer.append(previousText.substring(index, previousText.length()));
}
return buffer.toString();
}
}
To use the code above you need to add it to your current widget set.
Afterwards the use of this is as follows:
TextField field = new TextField();
NumberField.extend(field);

In Vaadin 7, you can use a TextField and set a validator to allow only numbers:
TextField textField;
textField.addValidator(new RegexpValidator("[-]?[0-9]*\\.?,?[0-9]+"), "This is not a number!");
Change the regex to fit your needs.
Remember that still is handling Strings and therefore you still need to convert the returning value of the TextField:
Long.parseLong(textField.getValue())

With Vaadin 8, you can use Binder:
Binder<YouBean> binder = new Binder<>();
binder.forField(textField)
.withConverter(new StringToIntegerConverter("Must be Integer"))
.bind(YouBean::getter, YouBean::setter);
binder.setBean(bean); //optional

A TextField is a component that always has a value of type String. When binding a property of another type to a text field, the value is automatically converted if the conversion between the two types is supported.
public class MyBean {
private int value;
public int getValue() {
return value;
}
public void setValue(int integer) {
value = integer;
}
}
The property named "value" from a BeanItem constructed from MyBean will be of type Integer. Binding the property to a TextField will automatically make validation fail for texts that can not be converted to an Integer.
final MyBean myBean = new MyBean();
BeanItem<MyBean> beanItem = new BeanItem<MyBean>(myBean);
final Property<Integer> integerProperty = (Property<Integer>) beanItem
.getItemProperty("value");
final TextField textField = new TextField("Text field", integerProperty);
Button submitButton = new Button("Submit value", new ClickListener() {
public void buttonClick(ClickEvent event) {
String uiValue = textField.getValue();
Integer propertyValue = integerProperty.getValue();
int dataModelValue = myBean.getValue();
Notification.show("UI value (String): " + uiValue
+ "\nProperty value (Integer): " + propertyValue
+ "\nData model value (int): " + dataModelValue);
}
});
addComponent(new Label("Text field type: " + textField.getType()));
addComponent(new Label("Text field type: " + integerProperty.getType()));
addComponent(textField);
addComponent(submitButton);
With this example, entering a number and pressing the button causes the value of the TextField to be a String, the property value will be an Integer representing the same value and the value in the bean will be the same int. If e.g. a letter is entered to the field and the button is pressed, the validation will fail. This causes a notice to be displayed for the field. The field value is still updated, but the property value and the bean value are kept at their previous values.

This is an update (2017 with vaadin 8) for #raffael answer:
public class DoubleField extends TextField implements ValueChangeListener<String> {
public String lastValue;
public DoubleField() {
setValueChangeMode(ValueChangeMode.EAGER);
addValueChangeListener(this);
lastValue="";
}
#Override
public void valueChange(ValueChangeEvent<String> event) {
String text = (String) event.getValue();
try {
new Double(text);
lastValue = text;
} catch (NumberFormatException e) {
setValue(lastValue);
}
}

NumberField is available for Vaadin 7 and 8 by now.

GWT: handling event in composite cell

CompositeCell let us customize the content of a table cell's in GWT using Java. We can put almost any other group of widget within the table's cell and layout them as we want. Problem is that if we used the html tags to define the layout of the CompositeCell as yet another table (see CompositeCell anonymous class implementation bellow) we loose the event handling for the components of the cell :(.
Running the following code, when we click in the buttons of the cell will realize the popup in response of the event handling IF WE COMMENT the CompositeCell anonymous implementation.
I've been debugging CompositeCell.onBrowserEvent(Context, Element, C, NativeEvent, ValueUpdater) because i think that the definition of the cell layout using HTML table tags breaks the event chain within GWT widgets hierarchy but haven't been successful so far.
Remark: both commented and uncommented versions of the code realize the same GUI layout. This example just intent to show that we loose event handling when customizing cell's content.
public class ActionCellTest implements EntryPoint {
private static final String SERVER_ERROR = "An error occurred while " + "attempting to contact the server. Please check your network "
+ "connection and try again.";
private final GreetingServiceAsync greetingService = GWT.create(GreetingService.class);
public void onModuleLoad() {
CellTable<Person> table = new CellTable<ActionCellTest.Person>();
final List<HasCell<Person, ?>> cells = new LinkedList<HasCell<Person, ?>>();
cells.add(new HasCellImpl("first name", new ActionCell.Delegate<Person>() {
#Override
public void execute(Person object) {
Window.alert(object.getFirstName());
}
}));
cells.add(new HasCellImpl("last name", new ActionCell.Delegate<ActionCellTest.Person>() {
#Override
public void execute(Person object) {
Window.alert(object.getLastName());
}
}));
CompositeCell<Person> cell = new CompositeCell<Person>(cells) {
#Override
public void render(Context context, Person value, SafeHtmlBuilder sb) {
sb.appendHtmlConstant("<table><tbody><tr>");
for (HasCell<Person, ?> hasCell : cells) {
render(context, value, sb, hasCell);
}
sb.appendHtmlConstant("</tr></tbody></table>");
}
#Override
protected <X> void render(Context context, Person value, SafeHtmlBuilder sb, HasCell<Person, X> hasCell) {
Cell<X> cell = hasCell.getCell();
sb.appendHtmlConstant("<td>");
cell.render(context, hasCell.getValue(value), sb);
sb.appendHtmlConstant("</td>");
}
#Override
protected Element getContainerElement(Element parent) {
return parent.getFirstChildElement().getFirstChildElement().getFirstChildElement();
}
};
table.addColumn(new TextColumn<ActionCellTest.Person>() {
#Override
public String getValue(ActionCellTest.Person object) {
return object.getFirstName() + " " + object.getLastName();
}
}, "name");
table.addColumn(new Column<Person, Person>(cell) {
#Override
public Person getValue(ActionCellTest.Person object) {
return object;
}
}, "composite");
LinkedList<Person> data = new LinkedList<ActionCellTest.Person>();
data.add(new Person("Amy", "Reed"));
data.add(new Person("Tim", "Gardner"));
table.setRowData(data);
RootPanel.get().add(table);
}
private class HasCellImpl implements HasCell<Person, Person> {
private ActionCell<Person> fCell;
public HasCellImpl(String text, Delegate<Person> delegate) {
fCell = new ActionCell<Person>(text, delegate);
}
#Override
public Cell<Person> getCell() {
return fCell;
}
#Override
public FieldUpdater<Person, Person> getFieldUpdater() {
return null;
}
#Override
public Person getValue(Person object) {
return object;
}
}
private class Person {
private String fFirstName;
private String fLastName;
public Person(String first, String last) {
fFirstName = first;
fLastName = last;
}
public String getFirstName() {
return fFirstName;
}
public String getLastName() {
return fLastName;
}
}
}

This is a known issue which will be fixed in the upcoming GWT 2.5 (a matter of weeks): http://code.google.com/p/google-web-toolkit/issues/detail?id=5714
(in the mean time, you can run off trunk or try backporting the change)