Question

I have implemented my own form field as IsEditor<LeafValueEditor<String>> that I’d like to use in the forms of my application.

public class FormField extends Composite implements IsEditor<LeafValueEditor<String>> {

    interface FormFieldUiBinder extends UiBinder<Widget, FormField> {
    }

    private static FormFieldUiBinder uiBinder = GWT.create(FormFieldUiBinder.class);

    interface FormFieldStyle extends CssResource {
        String error();
    }

    @UiField
    TextBox wrapped;

    private String placeholder;

    public FormField() {
        initWidget(uiBinder.createAndBindUi(this));
        wrapped.setTitle("");
    }

    @UiHandler("wrapped")
    public void onFocus(FocusEvent event) {
        Scheduler.get().scheduleDeferred(new ScheduledCommand() {
            @Override
            public void execute() {
                wrapped.selectAll();
            }
        });
    }

    public String getText() {
        return wrapped.getText();
    }

    public void setText(String text) {
            wrapped.setText(text);
    }

    /**
     * Gets the current placeholder text for the text box.
     * 
     * @return the current placeholder text
     */
    public String getPlaceholder() {
        return placeholder;
    }

    /**
     * Sets the placeholder text displayed in the text box.
     * 
     * @param placeholder
     *            the placeholder text
     */
    public void setPlaceholder(String text) {
        placeholder = (text != null ? text : "");
        wrapped.getElement().setPropertyString("placeholder", placeholder);
    }

    public String getTitle() {
        return wrapped.getTitle();
    }

    public void setTitle(String title) {
        wrapped.setTitle(title);
    }

    @Override
    public LeafValueEditor<String> asEditor() {
        return wrapped.asEditor();
    }

    public int getVisibleLength() {
        return wrapped.getVisibleLength();
    }

    public void setVisibleLength(int length) {
        wrapped.setVisibleLength(length);
    }

    public boolean isReadOnly() {
        return wrapped.isReadOnly();
    }

    public void setReadOnly(boolean readOnly) {
        wrapped.setReadOnly(readOnly);
    }

    public boolean isEnabled() {
        return wrapped.isEnabled();
    }

    public void setEnabled(boolean enabled) {
        wrapped.setEnabled(enabled);
    }

    public void setWidth(String width) {
        wrapped.setWidth(width);
    }

}

The corresponding UIBinder file is plain simple :

<ui:UiBinder xmlns:ui='urn:ui:com.google.gwt.uibinder'
    xmlns:g='urn:import:com.google.gwt.user.client.ui'>

    <g:HTMLPanel>
        <g:TextBox ui:field="wrapped" />
    </g:HTMLPanel>
</ui:UiBinder>

This works smoothly in the forms I create like this :

<g:AbsolutePanel width="350px" height="225px"
    styleName="{res.css.inputArea}">
    <g:at left='10' top='0'>
        <g:HTMLPanel width="350px">
            <h1>Personalia</h1>
        </g:HTMLPanel>
    </g:at>
    <g:at left='10' top='65'>
        <f:FormLabel text="voornaam" />
    </g:at>
    <g:at left='10' top='80'>
        <f:FormField ui:field="firstName" placeholder="voornaam" />
    </g:at>
    <g:at left='10' top='115'>
        <f:FormLabel text="achternaam" />
    </g:at>
    <g:at left='10' top='130'>
        <f:FormField ui:field="lastName" placeholder="achternaam"/>
    </g:at>
</g:AbsolutePanel>

In my views, I can then use the EditorDriver like this :

interface EditorDriver extends SimpleBeanEditorDriver<Account, AccountPersonaliaEditor> {
}
private final EditorDriver editorDriver = GWT.create(EditorDriver.class);

And populating the form works fine too

    editorDriver.initialize(editor);
    editorDriver.edit(presenter.getAccount());

As well as getting the values after editing :

Account account = editorDriver.flush();

Now I would like to implement feedback on the errors. I have the GWT Bean validation framework working fine too. I just need to show the errors.

So, what I am trying next, is to have the FormField implement HasEditorErrors. Here is my problem/question.

public class FormField extends Composite implements IsEditor<LeafValueEditor<String>>, HasEditorErrors<String> 

As soon as I implement this interface (even with a empty implementation), I run into the following compile time error :

[DEBUG] [klawtapp] - Rebinding com.example.screen.ui.center.AccountPersonaliaImpl.EditorDriver
    [DEBUG] [klawtapp] - Invoking generator com.google.gwt.editor.rebind.SimpleBeanEditorDriverGenerator
        [DEBUG] [klawtapp] - Creating Editor model for com.example.screen.ui.center.AccountPersonaliaImpl.EditorDriver
            [DEBUG] [klawtapp] - Descending into firstName
                [ERROR] [klawtapp] - Could not find a getter for path wrapped in proxy type java.lang.String
            [DEBUG] [klawtapp] - Descending into lastName
                [ERROR] [klawtapp] - Could not find a getter for path wrapped in proxy type java.lang.String
            [ERROR] [klawtapp] - Unable to create Editor model due to previous errors
[ERROR] [klawtapp] - Deferred binding failed for 'com.example.screen.ui.center.AccountPersonaliaImpl.EditorDriver'; expect subsequent failures

This seemed so trivial. I have tried adding getter/setter for wrapped but that does not really help.

EDIT: for a moment, I thought the solution would be to implement HasEditorErrors<LeafValueEditor<String>> instead of HasEditorErrors<String> to prevent descending the hierarchy to the wrapped TextBox, but the results are similar :

            [ERROR] [klawtapp] - Could not find a getter for path wrapped in proxy type com.google.gwt.editor.client.LeafValueEditor

Answer 1

Simply annotate your wrapped text box with @Editor.Ignore.

Alternatively, you could remove the implements IsEditor<LeafValueEditor<String>> and instead annotate the wrapped field with @Path("") (you’ll have to test with null values though if you might face them, as I’m not sure it’ll work well as-is).

Or you could choose to implement your own LeafValueEditor<String> instead of relying on the one from the TextBox.