| <!DOCTYPE html> |
| <html lang="en"> |
| <head> |
| <meta charset="utf-8"> |
| <meta name="viewport" content="width=device-width,initial-scale=1"> |
| <title>@Nullable (javax) :: Apache Isis</title> |
| <link rel="canonical" href="https://isis.apache.org/refguide/2.0.0-M3/applib-ant/Nullable.html"> |
| <meta name="generator" content="Antora 2.2.0"> |
| <link rel="stylesheet" href="../../../_/css/site.css"> |
| <link rel="stylesheet" href="../../../_/css/site-custom.css"> |
| <link href="https://fonts.googleapis.com/css?family=Open+Sans:300,300i,400,400i,700,700i|Raleway:300,400,500,700,800|Montserrat:300,400,700" rel="stylesheet"> |
| <link rel="home" href="https://isis.apache.org" title="Apache Isis"> |
| <link rel="next" href="MinLength.html" title="MinLength"> |
| <link rel="prev" href="NotPersistent.html" title="NotPersistent."> |
| </head> |
| <body class="article"> |
| <header class="header"> |
| <nav class="navbar"> |
| <div class="navbar-brand"> |
| <a class="navbar-item" href="https://isis.apache.org"> |
| <span class="icon"> |
| <img src="../../../_/img/isis-logo-48x48.png"></img> |
| </span> |
| <span>Apache Isis</span> |
| </a> |
| <button class="navbar-burger" data-target="topbar-nav"> |
| <span></span> |
| <span></span> |
| <span></span> |
| </button> |
| </div> |
| <div id="topbar-nav" class="navbar-menu"> |
| <a class="navbar-end"> |
| <div class="navbar-item has-dropdown is-hoverable"> |
| <a class="navbar-link" href="#">Quick Start</a> |
| <div class="navbar-dropdown"> |
| <span class="navbar-item navbar-heading">Starter Apps</span> |
| <a class="navbar-item" href="../../../docs/latest/starters/helloworld.html">Hello World</a> |
| <a class="navbar-item" href="../../../docs/latest/starters/simpleapp.html">Simple App</a> |
| <hr class="navbar-divider"/> |
| <span class="navbar-item navbar-heading">Demos & Tutorials</span> |
| <a class="navbar-item" href="../../../docs/latest/demo/about.html">Demo App</a> |
| <a class="navbar-item" href="https://danhaywood.gitlab.io/isis-petclinic-tutorial-docs/petclinic/1.16.2/intro.html">Petclinic (tutorial)</a> |
| <hr class="navbar-divider"/> |
| <span class="navbar-item navbar-heading">Resources</span> |
| <a class="navbar-item" href="../../../docs/latest/resources/cheatsheet.html">Cheatsheet</a> |
| <a class="navbar-item" href="../../../docs/latest/resources/icons.html">Icons</a> |
| </div> |
| </div> |
| <div class="navbar-item has-dropdown is-hoverable"> |
| <a class="navbar-link" href="#">Guides</a> |
| <div class="navbar-dropdown"> |
| <span class="navbar-item navbar-heading">Development</span> |
| <a class="navbar-item" href="../../../setupguide/latest/about.html">Setup Guide</a> |
| <hr class="navbar-divider"/> |
| <span class="navbar-item navbar-heading">Core</span> |
| <a class="navbar-item" href="../../../userguide/latest/about.html">User Guide</a> |
| <a class="navbar-item" href="../../../refguide/latest/about.html">Reference Guide</a> |
| <a class="navbar-item" href="../../../testing/latest/about.html">Testing Guide</a> |
| </div> |
| </div> |
| <div class="navbar-item has-dropdown is-hoverable"> |
| <a class="navbar-link" href="#">Libraries</a> |
| <div class="navbar-dropdown"> |
| <span class="navbar-item navbar-heading">For Use in Apps</span> |
| <a class="navbar-item" href="../../../subdomains/latest/about.html">Subdomain Libraries</a> |
| <a class="navbar-item" href="../../../valuetypes/latest/about.html">Value Types</a> |
| <hr class="navbar-divider"/> |
| <span class="navbar-item navbar-heading">Integrate between Apps</span> |
| <a class="navbar-item" href="../../../mappings/latest/about.html">Bounded Context Mapping Libraries</a> |
| <hr class="navbar-divider"/> |
| <span class="navbar-item navbar-heading">Other</span> |
| <a class="navbar-item" href="../../../incubator/latest/about.html">Incubator</a> |
| <a class="navbar-item" href="../../../legacy/latest/about.html">Legacy</a> |
| </div> |
| </div> |
| <div class="navbar-item has-dropdown is-hoverable"> |
| <a class="navbar-link" href="#">Components</a> |
| <div class="navbar-dropdown"> |
| <span class="navbar-item navbar-heading">Viewers</span> |
| <a class="navbar-item" href="../../../vw/latest/about.html">Wicket UI</a> |
| <a class="navbar-item" href="../../../vro/latest/about.html">Restful Objects (REST)</a> |
| <hr class="navbar-divider"/> |
| <span class="navbar-item navbar-heading">Security</span> |
| <a class="navbar-item" href="../../../security/latest/about.html">Security Guide</a> |
| <hr class="navbar-divider"/> |
| <span class="navbar-item navbar-heading">Persistence</span> |
| <a class="navbar-item" href="../../../pjdo/latest/about.html">DataNucleus (JDO)</a> |
| <hr class="navbar-divider"/> |
| <span class="navbar-item navbar-heading">Extensions</span> |
| <a class="navbar-item" href="../../../extensions/latest/about.html">Extensions Catalog</a> |
| </div> |
| </div> |
| <div class="navbar-item has-dropdown is-hoverable"> |
| <a class="navbar-link" href="#">Support</a> |
| <div class="navbar-dropdown"> |
| <span class="navbar-item navbar-heading">Contact</span> |
| <a class="navbar-item" href="../../../docs/latest/support/slack-channel.html">Slack</a> |
| <a class="navbar-item" href="../../../docs/latest/support/mailing-list.html">Mailing Lists</a> |
| <a class="navbar-item" href="https://issues.apache.org/jira/browse/ISIS">JIRA</a> |
| <a class="navbar-item" href="https://stackoverflow.com/questions/tagged/isis">Stack Overflow</a> |
| <hr class="navbar-divider"/> |
| <span class="navbar-item navbar-heading">Releases</span> |
| <a class="navbar-item" href="../../../docs/latest/downloads/how-to.html">Downloads</a> |
| <a class="navbar-item" href="../../../relnotes/latest/about.html">Release Notes</a> |
| <a class="navbar-item" href="../../../docs/latest/archive/1-x.html">Archive (1.x)</a> |
| <hr class="navbar-divider"/> |
| <span class="navbar-item navbar-heading">Framework</span> |
| <a class="navbar-item" href="../../../conguide/latest/about.html">Contributors' Guide</a> |
| <a class="navbar-item" href="../../../comguide/latest/about.html">Committers' Guide</a> |
| <a class="navbar-item" href="../../../core/latest/about.html">Core Design</a> |
| </div> |
| </div> |
| <div class="navbar-item has-dropdown is-hoverable"> |
| <a class="navbar-link" href="#">ASF</a> |
| <div class="navbar-dropdown"> |
| <a class="navbar-item" href="http://www.apache.org/">Apache Homepage</a> |
| <a class="navbar-item" href="https://www.apache.org/events/current-event">Events</a> |
| <a class="navbar-item" href="https://www.apache.org/licenses/">Licenses</a> |
| <a class="navbar-item" href="https://www.apache.org/security/">Security</a> |
| <a class="navbar-item" href="https://www.apache.org/foundation/sponsorship.html">Sponsorship</a> |
| <a class="navbar-item" href="https://www.apache.org/foundation/thanks.html">Thanks</a> |
| <hr class="navbar-divider"/> |
| <a class="navbar-item" href="https://whimsy.apache.org/board/minutes/Isis.html">PMC board minutes</a> |
| </div> |
| </div> |
| <a class="navbar-item" href="../../../docs/latest/about.html"> |
| <span class="icon"> |
| <img src="../../../_/img/home.png"></img> |
| </span> |
| </a> |
| </div> |
| </div> |
| </nav> |
| </header> |
| <div class="body "> |
| <div class="nav-container" data-component="refguide" data-version="2.0.0-M3"> |
| <aside class="nav"> |
| <div class="panels"> |
| <div class="nav-panel-pagination"> |
| <a class="page-previous" rel="prev" href="NotPersistent.html" title="NotPersistent."><span></span></a> |
| <a class="page-next" rel="next" |
| href="MinLength.html" title="MinLength"><span></span></a> |
| <!-- |
| page.parent doesn't seem to be set... |
| <a class="page-parent" rel="prev" href="about.html" title="NotPersistent."><span></span></a> |
| --> |
| </div> |
| <div class="nav-panel-menu is-active" data-panel="menu"> |
| <nav class="nav-menu"> |
| <h3 class="title"><a href="../about.html">Reference Guide</a></h3> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="0"> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="1"> |
| <button class="nav-item-toggle"></button> |
| <a class="nav-link" href="about.html">Annotations</a> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="Action.html">Action</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="ActionLayout.html">ActionLayout</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="Collection.html">Collection</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="CollectionLayout.html">CollectionLayout</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="Column.html">Column</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="Digits.html">Digits</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="Discriminator.html">Discriminator</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="DomainObject.html">DomainObject</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="DomainObjectLayout.html">DomainObjectLayout</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="DomainService.html">DomainService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="DomainServiceLayout.html">DomainServiceLayout</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="Facets.html">Facets</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="HomePage.html">HomePage</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="MemberOrder.html">MemberOrder</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="Mixin.html">Mixin</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="NotPersistent.html">NotPersistent.</a> |
| </li> |
| <li class="nav-item is-current-page" data-depth="2"> |
| <a class="nav-link" href="Nullable.html">Nullable</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="MinLength.html">MinLength</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="Parameter.html">Parameter</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="ParameterLayout.html">ParameterLayout</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="Pattern.html">Pattern</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="PersistenceCapable.html">PersistenceCapable</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="PrimaryKey.html">PrimaryKey</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="Programmatic.html">Programmatic</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="Property.html">Property</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="PropertyLayout.html">PropertyLayout</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="IsisSessionScope.html">RequestScoped</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="Title.html">Title</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="ViewModel.html">ViewModel</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="XmlJavaTypeAdapter.html">XmlJavaTypeAdapter</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="XmlRootElement.html">XmlRootElement</a> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="1"> |
| <button class="nav-item-toggle"></button> |
| <a class="nav-link" href="../applib-methods/about.html">Methods</a> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-methods/prefixes.html">Supporting Method Prefixes</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-methods/reserved.html">Reserved Methods</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-methods/lifecycle.html">Lifecycle Methods</a> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="1"> |
| <button class="nav-item-toggle"></button> |
| <a class="nav-link" href="../applib-classes/about.html">Classes</a> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-classes/events.html">Events</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-classes/ViewModel.html"><code>ViewModel</code></a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-classes/value-types.html">Value Types</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-classes/spec.html">Specification pattern</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-classes/i18n.html">i18n support</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-classes/roles-mixins-contributees.html">Roles, Mixins and Contributees</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-classes/utility.html">Utility Classes</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-classes/layout.html">Layout</a> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="1"> |
| <button class="nav-item-toggle"></button> |
| <a class="nav-link" href="../applib-svc/about.html">Domain Services</a> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/AcceptHeaderService.html">AcceptHeaderService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/ApplicationFeatureRepository.html">ApplicationFeatureRepository</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/AuditerService.html">AuditerService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/BookmarkService.html">BookmarkService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/BookmarkUiService.html">BookmarkUiService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/ClockService.html">ClockService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/CommandContext.html">CommandContext</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/CommandDtoProcessorService.html">CommandDtoProcessorService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/CommandExecutorService.html">CommandExecutorService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/CommandService.html">CommandService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/ConfigurationMenu.html">ConfigurationMenu</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/ConfigurationViewService.html">ConfigurationViewService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/ContentMappingService.html">ContentMappingService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/DeepLinkService.html">DeepLinkService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/EmailNotificationService.html">EmailNotificationService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/EmailService.html">EmailService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/ErrorReportingService.html">ErrorReportingService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/EventBusService.html">EventBusService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/ExceptionRecognizerService.html">ExceptionRecognizerService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/FactoryService.html">FactoryService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/GridLoaderService.html">GridLoaderService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/GridService.html">GridService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/GridSystemService.html">GridSystemService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/HealthCheckService.html">HealthCheckService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/HintStore.html">HintStore</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/HomePageResolverService.html">HomePageResolverService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/InteractionContext.html">InteractionContext</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/JaxbService.html">JaxbService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/LayoutService.html">LayoutService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/LayoutServiceMenu.html">LayoutServiceMenu</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/LocaleProvider.html">LocaleProvider</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/MenuBarsLoaderService.html">MenuBarsLoaderService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/MenuBarsService.html">MenuBarsService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/MessageService.html">MessageService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/MetaModelService.html">MetamodelService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/MetaModelServiceMenu.html">MetamodelServiceMenu</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/MetricsService.html">MetricsService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/PublisherService.html">PublisherService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/QueryResultsCache.html">QueryResultsCache</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/RepositoryService.html">RepositoryService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/RoutingService.html">RoutingService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/Scratchpad.html">Scratchpad</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/ServiceInjector.html">ServiceInjector</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/ServiceRegistry.html">ServiceRegistry</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/SessionLoggingService.html">SessionLoggingService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/SudoService.html">SudoService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/SwaggerService.html">SwaggerService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/TableColumnOrderService.html">TableColumnOrderService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/TitleService.html">TitleService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/TranslationService.html">TranslationService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/TranslationsResolver.html">TranslationsResolver</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/TransactionService.html">TransactionService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/UrlEncodingService.html">UrlEncodingService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/UserProfileService.html">UserProfileService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/UserRegistrationService.html">UserRegistrationService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/UserService.html">UserService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/WrapperFactory.html">WrapperFactory</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/XmlService.html">XmlService</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../applib-svc/XmlSnapshotService.html">XmlSnapshotService</a> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="1"> |
| <button class="nav-item-toggle"></button> |
| <a class="nav-link" href="../config/about.html">Configuration</a> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.applib.html">Applib</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.core.meta-model.html">Core MetaModel</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.core.meta-model.introspector.html">Core MetaModel Introspection</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.core.meta-model.validator.html">MetaModel Validator</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.core.runtime.html">Core Runtime Services configurations</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.core.runtime-services.html">Core Runtime Services configurations</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.security.shiro.html">Shiro Security Implementation</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.persistence.jdo-datanucleus.html">JDO DataNucleus</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.persistence.jdo-datanucleus.impl.html">DataNucleus Configuration</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.viewer.restfulobjects.html">Restful Objects Viewer</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.viewer.wicket.html">Wicket Viewer</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.extensions.html">Extensions</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.value-types.html">Value types</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.testing.html">Testing</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/isis.legacy.html">Legacy</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/resteasy.html">RestEasy Configuration</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../config/sections/Other.html">Other</a> |
| </li> |
| </ul> |
| </li> |
| <li class="nav-item" data-depth="1"> |
| <button class="nav-item-toggle"></button> |
| <a class="nav-link" href="../schema/about.html">Schema</a> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../schema/mml.html">MetaModel</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../schema/cmd.html">Command</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../schema/ixn.html">Interaction</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../schema/chg.html">Changes</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../schema/common.html">Common</a> |
| </li> |
| </ul> |
| </li> |
| </ul> |
| </li> |
| </ul> |
| </nav> |
| </div> |
| <div class="nav-panel-explore" data-panel="explore"> |
| <div class="context"> |
| <span class="title">Reference Guide</span> |
| <span class="version">2.0.0-M3</span> |
| </div> |
| <ul class="components"> |
| <li class="component"> |
| <span class="title"> </span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../docs/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">BC Mappings Catalog</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../mappings/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">Committers' Guide</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../comguide/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">Contributors' Guide</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../conguide/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">Design Docs</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../core/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">Extensions Catalog</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../extensions/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">Incubator Catalog</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../incubator/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">JDO/DataNucleus</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../pjdo/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">Legacy Catalog</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../legacy/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component is-current"> |
| <span class="title">Reference Guide</span> |
| <ul class="versions"> |
| <li class="version is-current is-latest"> |
| <a href="../about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">Release Notes</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../relnotes/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">Restful Objects Viewer</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../vro/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">Security Guide</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../security/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">Setup Guide</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../setupguide/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">Subdomains Catalog</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../subdomains/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">Testing Guide</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../testing/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">User Guide</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../userguide/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">Value Types Catalog</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../valuetypes/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| <li class="component"> |
| <span class="title">Wicket Viewer</span> |
| <ul class="versions"> |
| <li class="version is-latest"> |
| <a href="../../../vw/2.0.0-M3/about.html">2.0.0-M3</a> |
| </li> |
| </ul> |
| </li> |
| </ul> |
| </div> |
| </div> |
| </aside> |
| </div> |
| <main role="main"> |
| <div class="toolbar" role="navigation"> |
| <button class="nav-toggle"></button> |
| <a href="../../../docs/2.0.0-M3/about.html" class="home-link"></a> |
| <nav class="breadcrumbs" aria-label="breadcrumbs"> |
| <ul> |
| <li><a href="../about.html">Reference Guide</a></li> |
| <li><a href="about.html">Annotations</a></li> |
| <li><a href="Nullable.html">Nullable</a></li> |
| </ul> |
| </nav> |
| <div class="edit-this-page"><a href="https://github.com/apache/isis/edit/2.0.0-M3/api/applib/src/main/adoc/modules/applib-ant/pages/Nullable.adoc">Edit</a></div> |
| </div> |
| <article class="doc"> |
| <a name="section-top"></a> |
| <h1 class="page"><code>@Nullable</code> (<code>javax</code>)</h1> |
| <div class="paragraph"> |
| <p>Apache Isis' defaults for properties and parameters is that they are mandatory unless otherwise stated. |
| The <code>@javax.annotation.Nullable</code> annotation is recognized by Apache Isis for both properties and parameters as means to indicate that the property/parameter is not mandatory.</p> |
| </div> |
| <div class="paragraph"> |
| <p>For example:</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="highlightjs highlight"><code class="language-java hljs" data-lang="java">@javax.annotation.Nullable |
| public String getName() { |
| return name; |
| } |
| public void setName(final String name) { |
| this.name = name; |
| }</code></pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>or:</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre class="highlightjs highlight"><code class="language-java hljs" data-lang="java">public Customer updateName(@javax.annotation.Nullable final String name) { |
| setName(name); |
| return this; |
| }</code></pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>Apache Isis does provide several other ways to specify optionality: using the |
| <a href="Property.html#optionality" class="page"><code>@Property#optionality()</code></a> / |
| <a href="Parameter.html#optionality" class="page"><code>@Parameter#optionality()</code></a> annotation. |
| For properties, the optionality can also be inferred from the <a href="Column.html#allowsNull.adoc" class="page"><code>@Column#allowsNull()</code></a> attribute.</p> |
| </div> |
| <div class="admonitionblock tip"> |
| <table> |
| <tr> |
| <td class="icon"> |
| <i class="fa icon-tip" title="Tip"></i> |
| </td> |
| <td class="content"> |
| <div class="paragraph"> |
| <p>See the |
| <a href="Property.html#optionality" class="page"><code>@Property#optionality()</code></a> documentation for a much fuller discussion on the relationship between using the Apache Isis annotations vs |
| <a href="Column.html#allowsNull.adoc" class="page"><code>@Column#allowsNull()</code></a>.</p> |
| </div> |
| </td> |
| </tr> |
| </table> |
| </div> |
| <div class="paragraph"> |
| <p>If more than one method is specified then the framework will validate that there are no incompatibilities (and fail to boot otherwise). |
| This can also be verified using the <a href="#refguide:mvn:validate.adoc" class="page unresolved">validate goal</a> of the Apache Isis Maven plugin.</p> |
| </div> |
| </article> |
| <aside class="article-aside toc" role="navigation"> |
| <p class="toc-title">On this page</p> |
| <div id="article-toc"></div> |
| </aside> |
| </main> |
| </div> |
| <footer class="footer"> |
| <div class="content"> |
| <div class="copyright"> |
| <p> |
| Copyright © 2010~2020 The Apache Software Foundation, licensed under the Apache License, v2.0. |
| <br/> |
| Apache, the Apache feather logo, Apache Isis, and the Apache Isis project logo are all trademarks of The Apache Software Foundation. |
| </p> |
| </div> |
| <div class="revision"> |
| <p>Revision: SNAPSHOT</p> |
| </div> |
| </div> |
| </footer> |
| <script src="../../../_/js/site.js"></script> |
| <script async src="../../../_/js/vendor/highlight.js"></script> |
| <script src="../../../_/js/vendor/jquery-3.4.1.min.js"></script> |
| <script src="../../../_/js/vendor/jquery-ui-1.12.1.custom.widget-only.min.js"></script> |
| <script src="../../../_/js/vendor/jquery.tocify.min.js"></script> |
| |
| <script> |
| $(function() { |
| $("#article-toc").tocify( { |
| showEffect: "slideDown", |
| hashGenerator: "pretty", |
| hideEffect: "slideUp", |
| selectors: "h2, h3", |
| scrollTo: 120, |
| smoothScroll: true, |
| theme: "jqueryui", |
| highlightOnScroll: true |
| } ); |
| }); |
| </script> |
| </body> |
| </html> |
