GUI Design Meeting

Last modified 12 Mar 2021 10:22 +01:00
  • Use model where possible - do not do complex loading outside the model when possible. Think about Hollywood principle: "Don’t Call Us, We’ll Call You". But be careful, using Model.of(someLoadingFromModel) is not the model we are talking about.

  • Use compiled GUI profile where possible - there is a system config, credentials config, etc. We don’t need to load them again when they were loaded before.

    • Compiled GUI profile may need improvement and cleanup. E.g. unify with "getAssignableRoles".

  • Create DTO or other GUI related object when needed - e.g. don’t try to make complex transformation and acrobatics when it’s simpler to create custom DTO object.

  • Think about model resolution - how many times getObject() is called?

  • Use visible enable behavior and not do any if-else statements. Especially if there is a need to call model/repo/provisioning.

  • When there is a need to set CSS or styles in Java code, think if there isn’t native way of using CSS instead. Every component.add() method costs something.

  • Read wicket documentation, especially the part about anti-patterns.

  • When you change, refactor panel, method, anything. If there is a parameter in the method which is not used in the method body, remove it from method signature. It doesn’t have any meaning to keep it there!

  • Improve error handling little by little, e.g. if there is something like this:

    try {
        allowAddNew = parentPage.isAuthorized(ModelAuthorizationAction.ADD.getUrl(),
        AuthorizationPhaseType.REQUEST, (new OrgType(parentPage.getPrismContext())).asPrismObject(),
        null, null, null);
    } catch (SchemaException | ExpressionEvaluationException | ObjectNotFoundException
    | CommunicationException | ConfigurationException | SecurityViolationException ex) {
        LoggingUtils.logUnexpectedException(LOGGER, "Failed to check menu items authorizations", ex);
    }

    change it to:

    try {
        allowAddNew = parentPage.isAuthorized(ModelAuthorizationAction.ADD.getUrl(),
        AuthorizationPhaseType.REQUEST, (new OrgType(parentPage.getPrismContext())).asPrismObject(),
        null, null, null);
    } catch (Throwable ex) {
        LoggingUtils.logUnexpectedException(LOGGER, "Failed to check menu items authorizations", ex);
    }

    It might seem as an anti-pattern, but we have to think that we are in GUI, the most upper layer in the system. So if we don’t have any reasonable way how to handle exceptions, it’s safer and better to catch them all, log them, add to the result and show the error message to the user and so prevent GUI crashes

Known Issues

  • toolbarButtons on the main table component - buttons descriptions are loaded out of the model scope. It leads to more calls then needed. Use model instead. Review and fix MultifunctionalButton.

  • left menu panel - everything is loaded every time the page is loaded. When there is a lot of dashboards or collections defined, it might slow the entire GUI. Questions

    • do we need to load everything every time? Even when it’s not display? Can’t we use models somehow?

    • What about dashboards? They are displayed automatically when new dashboard is created? Don’t we want similar mechanism as with collections which have to be explicitly enabled in adminGuiConfig?

  • There is a problem with wrappers and generated forms - the model object has to be loaded before the createPanel is called. It’s because the panels are registered while creating wrapper and wrapper is created only if the model.getObject() is called. Could this be a memory problem with many simultaneous sessions? We need probably different mechanism, e.g. what about having generic panels for PrismProperty, PrismReference, PrismContainer and all compile-time know panels? And then, using system configuration or some override mechanism, other then implemented now (directly while creating wrapper) could be those panels overridden and custom panels used instead?

  • Page org tree (TreeTablePanel):

    • a lot of components with bad handling, e.g. there is a member panel and manager panels. Both makes call to load members/managers. As there is misuse of models, these calls are repeated several times.

    • member panel use MainObjectListPanel which has the perf. issues itself (toolbarButtons).

    • manager panel - why to create objectWrapper which isn’t event used?

    • loading of the children of org.

    • setParent (as well as in AbstractOrgTabPanel)

  • AbstractRoleMemberPanel:

    • initSearch - use models!

    • initDefaultSearchParameters - use models! what is this acrobatics about?

  • AssignmentPanel

    • newButtonDescription

  • Search panel - support for "static" filters, e.g. on member table, there is "static" filer for type, indirect, scope (org), relation. On repository objects, when searching shadows, there is resource, objectClass, for all objects, there is oid.