Hints and Tips

This chapter provides some solutions for problems we’ve encountered ourselves or have been raised on the mailing lists/Slack channel.

Per-user Themes

From this thread on the Apache Isis users mailing list:

Is it possible to have each of our resellers (using our Apache Isis application) use their own theme/branding with their own logo and colors? Would this also be possible for the login page, possibly depending on the used host name?

Yes, you can do this, by installing a custom implementation of the Wicket Bootstrap’s ActiveThemeProvider:

IActiveThemeProvider implementation

public class UserSettingsThemeProvider implements ActiveThemeProvider {
    ...
    @Override
    public ITheme getActiveTheme() {
        if(IsisContext.getSpecificationLoader().isInitialized()) {
            final String themeName = IsisContext.doInSession(new Callable<String>() {
                @Override
                public String call() throws Exception {
                    final UserSettingsService userSettingsService =
                        lookupService(UserSettingsService.class);
                    final UserSetting activeTheme = userSettingsService.find(
                            IsisContext.getAuthenticationSession().getUserName(),
                            ACTIVE_THEME);
                    return activeTheme != null ? activeTheme.valueAsString() : null;
                }
            });
            return themeFor(themeName);
        }
        return new SessionThemeProvider().getActiveTheme();
    }
    @Override
    public void setActiveTheme(final String themeName) {
        IsisContext.doInSession(new Runnable() {
            @Override
            public void run() {
                final String currentUsrName =
                    IsisContext.getAuthenticationSession().getUserName();
                final UserSettingsServiceRW userSettingsService =
                        lookupService(UserSettingsServiceRW.class);
                final UserSettingJdo activeTheme =
                        (UserSettingJdo) userSettingsService.find(
                                                currentUsrName, ACTIVE_THEME);
                if(activeTheme != null) {
                    activeTheme.updateAsString(themeName);
                } else {
                    userSettingsService.newString(
                        currentUsrName, ACTIVE_THEME, "Active Bootstrap theme for user", themeName);
                }
            }
        });
    }
    private ITheme themeFor(final String themeName) {
        final ThemeProvider themeProvider = settings.getThemeProvider();
        if(themeName != null) {
            for (final ITheme theme : themeProvider.available()) {
                if (themeName.equals(theme.name()))
                    return theme;
            }
        }
        return themeProvider.defaultTheme();
    }
    ...
}

and

Using the ActiveThemeProvider

@Override
protected void init() {
    super.init();

    final IBootstrapSettings settings = Bootstrap.getSettings();
    settings.setThemeProvider(new BootswatchThemeProvider(BootswatchTheme.Flatly));

    settings.setActiveThemeProvider(new UserSettingsThemeProvider(settings));
}

How i18n the Wicket viewer?

From this thread on the Apache Isis users mailing list:

I am trying to internationalize the label descriptions of form actions, eg those in ActionParametersFormPanel. Referencing those via their message id inside a .po file didn’t work either. Can this be done?

Yes, it is possible to internationalize both the Wicket viewer’s labels as well as the regular translations of the domain object metadata using the .po translation files as supported by the TranslationService.

Full details of the msgIds that must be added to the translations.po file can be found in i18n section of the beyond the basics guide.

Auto-refresh page

This requirement from the users mailing list:

"Suppose you want to build a monitoring application, eg for an electricity grid. Data is updated in the background (eg via the Restful Objects REST API). What is needed is the ability to show an entity that includes a map, and have it auto-refresh every 5 seconds or so."

Here’s one (somewhat crude, but workable) way to accomplish this.

First, update the domain object to return custom CSS:

public class MyDomainObject {
    ...
    public String cssClass() { return "my-special-auto-updating-entity"; }
    ...
}

Then, use custom JavaScript to reload:

scripts/application.js

$(function() {
    if ($(".my-special-auto-updating-entity").length) {
        setTimeout(function() {document.location.reload();}, 5000); // 1000 is 5 sec
    }
});

SVG Support

(As per ISIS-1604), SVG images can be used:

as Logo in the upper left corner (Wicket Menubar)
on the Login Page (login.html)
as favicon (image/svg+xml, cf. ISIS-1115)

However, SVGs are not, by default, displayed on the welcome page. SVGs can be attached as Blobs, but they are displayed as bitmaps (by means of the Batik rasterizer) and do not scale. The rasterizer (of course) can not deal with animations (cf. attachment).

To fix this, you can add the following dependencies:

<dependency>
    <groupId>com.twelvemonkeys.imageio</groupId>
    <artifactId>imageio-batik</artifactId> <!-- svg -->
    <version>3.3.2</version>
</dependency>
<dependency>
    <groupId>com.twelvemonkeys.imageio</groupId>
    <artifactId>imageio-batik</artifactId> <!-- svg -->
    <version>3.3.2</version>
    <type>test-jar</type>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.apache.xmlgraphics</groupId>
    <artifactId>batik-transcoder</artifactId>
    <version>1.8</version>
</dependency>

However, please note that these dependencies have high CVE values, and so may constitute a security risk.

Further discussion on this mailing list thread.