documentation/subprojects/apache-felix-metatype-service.html - felix-site-pub - Git at Google

 <!DOCTYPE html>
 <html lang="en">
   <head>
     <meta charset="utf-8">
     <meta name="viewport" content="width=device-width,initial-scale=1">
     <title>Apache Felix Metatype Service :: Apache Felix</title>
     <link rel="canonical" href="https://felix.apache.org/documentation/subprojects/apache-felix-metatype-service.html">
     <meta name="generator" content="Antora 2.3.4">
     <link rel="stylesheet" href="../../_/css/site.css">
     <link rel="icon" href="../../_/img/favicon.png" type="image/x-icon">
   </head>
   <body class="article">
 <header class="header">
   <nav class="navbar">
     <div class="navbar-brand">
       <a class="navbar-item" href="https://felix.apache.org/index.html">
         <span>
           <img src="../../_/img/logo.png">
         </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">
       <div class="navbar-end">
         <a class="navbar-item" href="https://felix.apache.org/index.html">Home</a>
         <div class="navbar-item has-dropdown is-hoverable">
           <a class="navbar-link" href="#">Subprojects</a>
           <div class="navbar-dropdown">
             <a class="navbar-item" href="apache-felix-dependency-manager.html">Dependency Manager</a>
             <a class="navbar-item" href="apache-felix-event-admin.html">Event Admin</a>
             <a class="navbar-item" href="apache-felix-file-install.html">File Install</a>
             <a class="navbar-item" href="apache-felix-framework.html">Framework</a>
             <a class="navbar-item" href="apache-felix-gogo.html">Gogo Shell</a>
             <a class="navbar-item" href="apache-felix-healthchecks.html">Health Checks</a>
             <a class="navbar-item" href="apache-felix-inventory.html">Inventory</a>
             <a class="navbar-item" href="apache-felix-log.html">Log</a>
             <a class="navbar-item" href="apache-felix-logback.html">Logback</a>
             <a class="navbar-item" href="apache-felix-maven-bundle-plugin.html">Maven bundle plugin</a>
             <a class="navbar-item" href="apache-felix-maven-scr-plugin.html">Maven SCR plugin</a>
             <a class="navbar-item" href="apache-felix-metatype-service.html">Metatype Service</a>
             <a class="navbar-item" href="apache-felix-preferences-service.html">Preferences Service</a>
             <a class="navbar-item" href="apache-felix-remote-shell.html">Remote Shell</a>
             <a class="navbar-item" href="apache-felix-script-console-plugin.html">Script console plugin</a>
             <a class="navbar-item" href="apache-felix-shell.html">Lightweight shell</a>
             <a class="navbar-item" href="apache-felix-shell-tui.html">Shell TUI</a>
             <a class="navbar-item" href="apache-felix-web-console.html">Web Console</a>
           </div>
         </div>
         <div class="navbar-item">
           <span class="control">
             <a class="button is-primary" href="../downloads.html">Downloads</a>
           </span>
         </div>
       </div>
     </div>
   </nav>
 </header>
 <div class="body">
 <div class="nav-container" data-component="documentation" data-version="master">
   <aside class="nav">
     <div class="panels">
 <div class="nav-panel-menu is-active" data-panel="menu">
   <nav class="nav-menu">
     <h3 class="title"><a href="../index.html">Documentation</a></h3>
 <ul class="nav-list">
   <li class="nav-item" data-depth="0">
 <ul class="nav-list">
   <li class="nav-item" data-depth="1">
     <a class="nav-link" href="../documentation.html">Documentation</a>
   </li>
   <li class="nav-item" data-depth="1">
     <a class="nav-link" href="../downloads.html">Downloads</a>
   </li>
   <li class="nav-item" data-depth="1">
     <a class="nav-link" href="../getting-started.html">Getting Started</a>
   </li>
   <li class="nav-item" data-depth="1">
     <a class="nav-link" href="../news.html">News</a>
   </li>
   <li class="nav-item" data-depth="1">
     <button class="nav-item-toggle"></button>
     <span class="nav-text">Community</span>
 <ul class="nav-list">
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="../community/project-info.html">Apache Felix Project Info</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="../community/contributing.html">Contributing</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="../community/projects-using-felix.html">Projects Using Felix</a>
   </li>
 </ul>
   </li>
   <li class="nav-item" data-depth="1">
     <button class="nav-item-toggle"></button>
     <span class="nav-text">Development</span>
 <ul class="nav-list">
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="../development/coding-standards.html">Coding Standards</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="../development/dependencies-file-template.html">DEPENDENCIES file template</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="../development/provisional-osgi-api-policy.html">Provisional OSGi API Policy</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="../development/release-management-nexus.html">Release Management</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="../development/site-how-to.html">Site How To</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="../development/using-the-osgi-compliance-tests.html">Using the OSGi Compliance Tests</a>
   </li>
 </ul>
   </li>
   <li class="nav-item" data-depth="1">
     <button class="nav-item-toggle"></button>
     <a class="nav-link" href="../faqs.html">FAQS</a>
 <ul class="nav-list">
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="../faqs/apache-felix-bundle-plugin-faq.html">Apache Felix Bundle Plugin Frequently Asked Questions</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="../faqs/apache-felix-scr-plugin-faq.html">Apache Felix SCR Plugin Frequently Asked Questions</a>
   </li>
 </ul>
   </li>
   <li class="nav-item" data-depth="1">
     <button class="nav-item-toggle"></button>
     <a class="nav-link" href="../subprojects.html">Subprojects</a>
 <ul class="nav-list">
   <li class="nav-item" data-depth="2">
     <button class="nav-item-toggle"></button>
     <a class="nav-link" href="apache-felix-dependency-manager.html">Apache Felix Dependency Manager</a>
 <ul class="nav-list">
   <li class="nav-item" data-depth="3">
     <button class="nav-item-toggle"></button>
     <span class="nav-text">Guides</span>
 <ul class="nav-list">
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/guides/migrating-from-earlier-versions.html">Apache Felix Dependency Manager - Migrating from earlier versions</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/guides/annotations.html">Dependency Manager - Annotations</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/guides/background.html">Dependency Manager - Background</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/guides/bundles-and-dependencies.html">Dependency Manager - Bundles and Dependencies</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/guides/design-patterns.html">Dependency Manager - Design Patterns</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/guides/development.html">Dependency Manager - Development</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/guides/history.html">Dependency Manager - History</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/guides/javadocs.html">Dependency Manager - JavaDocs</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/guides/migrating-from-other-solutions.html">Dependency Manager - Migrating from other solutions.</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/guides/performance-tuning.html">Dependency Manager - Performance Tuning</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/guides/resources.html">Dependency Manager - Resource adapters</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/guides/whatsnew.html">Dependency Manager - What&#8217;s new in version 4?</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/guides/dm-lambda.html">Dependency Manager Lambda</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/guides/whatsnew-r15.html">What&#8217;s New in R15</a>
   </li>
 </ul>
   </li>
   <li class="nav-item" data-depth="3">
     <button class="nav-item-toggle"></button>
     <span class="nav-text">Reference</span>
 <ul class="nav-list">
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/component-adapter.html">Dependency Manager - Adapter</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/component-aspect.html">Dependency Manager - Aspect</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/component-bundle-adapter.html">Dependency Manager - Bundle Adapter</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/dependency-bundle.html">Dependency Manager - Bundle Dependency</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/components.html">Dependency Manager - Components</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/dependency-configuration.html">Dependency Manager - Configuration Dependency</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/dependencies.html">Dependency Manager - Dependencies</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/external-links.html">Dependency Manager - External Links</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/component-factory-configuration-adapter.html">Dependency Manager - Factory Configuration Adapter Service</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/component-resource-adapter.html">Dependency Manager - Resource Adapter</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/dependency-resource.html">Dependency Manager - Resource Dependency</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/dependency-service.html">Dependency Manager - Service Dependency</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/service-scopes.html">Dependency Manager - Service Scopes</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/component-singleton.html">Dependency Manager - Singleton Component</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/thread-model.html">Dependency Manager - Thread Model</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/reference/dm-annotations.html">Dependency Manager Annotations</a>
   </li>
 </ul>
   </li>
   <li class="nav-item" data-depth="3">
     <button class="nav-item-toggle"></button>
     <span class="nav-text">Tutorials</span>
 <ul class="nav-list">
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/tutorials/working-with-annotations.html">Dependency Manager - Annotations</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/tutorials/getting-started.html">Dependency Manager - Getting Started</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/tutorials/leveraging-the-shell.html">Dependency Manager - Leveraging the shell</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-dependency-manager/tutorials/sample-code.html">Dependency Manager sample projects</a>
   </li>
 </ul>
   </li>
 </ul>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="apache-felix-event-admin.html">Apache Felix Event Admin</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="apache-felix-file-install.html">Apache Felix File Install</a>
   </li>
   <li class="nav-item" data-depth="2">
     <button class="nav-item-toggle"></button>
     <a class="nav-link" href="apache-felix-framework.html">Apache Felix Framework</a>
 <ul class="nav-list">
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-framework/apache-felix-framework-bundle-cache.html">Apache Felix Framework Bundle Cache</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-framework/apache-felix-framework-configuration-properties.html">Apache Felix Framework Configuration Properties</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-framework/apache-felix-framework-faq.html">Apache Felix Framework Frequently Asked Questions</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-framework/apache-felix-framework-launching-and-embedding.html">Apache Felix Framework Launching and Embedding</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-framework/apache-felix-framework-usage-documentation.html">Apache Felix Framework Usage Documentation</a>
   </li>
 </ul>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="apache-felix-framework-security.html">Apache Felix Framework Security</a>
   </li>
   <li class="nav-item" data-depth="2">
     <button class="nav-item-toggle"></button>
     <a class="nav-link" href="apache-felix-gogo.html">Apache Felix Gogo</a>
 <ul class="nav-list">
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-gogo/rfc-147-overview.html">RFC 147 Overview</a>
   </li>
 </ul>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="apache-felix-healthchecks.html">Apache Felix Health Checks</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="apache-felix-inventory.html">Apache Felix Inventory Printer</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="apache-felix-log.html">Apache Felix Log</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="apache-felix-logback.html">Apache Felix Logback</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="apache-felix-maven-bundle-plugin-bnd.html">Apache Felix Maven Bundle Plugin (BND)</a>
   </li>
   <li class="nav-item is-current-page" data-depth="2">
     <a class="nav-link" href="apache-felix-metatype-service.html">Apache Felix Metatype Service</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="apache-felix-osgi-bundle-repository.html">Apache Felix OSGi Bundle Repository (OBR)</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="apache-felix-preferences-service.html">Apache Felix Preferences Service</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="apache-felix-remote-shell.html">Apache Felix Remote Shell</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="apache-felix-shell.html">Apache Felix Shell</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="apache-felix-shell-tui.html">Apache Felix Shell TUI</a>
   </li>
   <li class="nav-item" data-depth="2">
     <button class="nav-item-toggle"></button>
     <a class="nav-link" href="apache-felix-web-console.html">Apache Felix Web Console</a>
 <ul class="nav-list">
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-web-console/extending-the-apache-felix-web-console.html">Extending the Apache Felix Web Console</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-web-console/web-console-restful-api.html">Web Console RESTful API</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-web-console/web-console-security-provider.html">Web Console Security Provider</a>
   </li>
   <li class="nav-item" data-depth="3">
     <button class="nav-item-toggle"></button>
     <span class="nav-text">Extensions</span>
 <ul class="nav-list">
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-web-console/extending-the-apache-felix-web-console/branding-the-web-console.html">Branding the Web Console</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-web-console/extending-the-apache-felix-web-console/providing-resources.html">Providing Resources</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-web-console/extending-the-apache-felix-web-console/providing-web-console-plugins.html">Providing Web Console Plugins</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-web-console/extending-the-apache-felix-web-console/web-console-logging.html">Web Console Logging</a>
   </li>
   <li class="nav-item" data-depth="4">
     <a class="nav-link" href="apache-felix-web-console/extending-the-apache-felix-web-console/web-console-output-templating.html">Web Console Output Templating</a>
   </li>
 </ul>
   </li>
 </ul>
   </li>
   <li class="nav-item" data-depth="2">
     <button class="nav-item-toggle"></button>
     <span class="nav-text">Maven SCR plugin</span>
 <ul class="nav-list">
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-maven-scr-plugin/apache-felix-maven-scr-plugin-use.html">Apache Felix Maven SCR Plugin Use</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-maven-scr-plugin/apache-felix-scr-bndtools-use.html">Apache Felix SCR Annotations BndTools Use</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-maven-scr-plugin/apache-felix-scr-ant-task-use.html">Apache Felix SCR Ant Task Use</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-maven-scr-plugin/extending-scr-annotations.html">Extending SCR Annotations Excerpt: How add new Annotations extending the base Annotations</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-maven-scr-plugin/scr-annotations.html">SCR Annotations Excerpt: Using Java 5 Annotations to describe the component or service.</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="apache-felix-maven-scr-plugin/scr-javadoc-tags.html">SCR JavaDoc Tags Excerpt: Using JavaDoc Tags to describe the component or service.</a>
   </li>
 </ul>
   </li>
 </ul>
   </li>
   <li class="nav-item" data-depth="1">
     <button class="nav-item-toggle"></button>
     <a class="nav-link" href="../tutorials-examples-and-presentations.html">Tutorials</a>
 <ul class="nav-list">
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="../tutorials-examples-and-presentations/apache-felix-application-demonstration.html">Apache Felix Application Demonstration</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="../tutorials-examples-and-presentations/apache-felix-osgi-tutorial.html">Apache Felix OSGi Tutorial</a>
   </li>
   <li class="nav-item" data-depth="2">
     <a class="nav-link" href="../tutorials-examples-and-presentations/apache-felix-osgi-faq.html">OSGi Frequently Asked Questions</a>
   </li>
   <li class="nav-item" data-depth="2">
     <button class="nav-item-toggle"></button>
     <span class="nav-text">OSGI Tutorial</span>
 <ul class="nav-list">
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="../tutorials-examples-and-presentations/apache-felix-osgi-tutorial/apache-felix-tutorial-example-1.html">Apache Felix Tutorial Example 1 - Service Event Listener Bundle</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="../tutorials-examples-and-presentations/apache-felix-osgi-tutorial/apache-felix-tutorial-example-2.html">Apache Felix Tutorial Example 2</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="../tutorials-examples-and-presentations/apache-felix-osgi-tutorial/apache-felix-tutorial-example-2b.html">Apache Felix Tutorial Example 2b</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="../tutorials-examples-and-presentations/apache-felix-osgi-tutorial/apache-felix-tutorial-example-3.html">Apache Felix Tutorial Example 3</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="../tutorials-examples-and-presentations/apache-felix-osgi-tutorial/apache-felix-tutorial-example-4.html">Apache Felix Tutorial Example 4</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="../tutorials-examples-and-presentations/apache-felix-osgi-tutorial/apache-felix-tutorial-example-5.html">Apache Felix Tutorial Example 5</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="../tutorials-examples-and-presentations/apache-felix-osgi-tutorial/apache-felix-tutorial-example-6.html">Example 6 - Spell Checker Service Bundle</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="../tutorials-examples-and-presentations/apache-felix-osgi-tutorial/apache-felix-tutorial-example-7.html">Example 7 - Spell Checker Client Bundle</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="../tutorials-examples-and-presentations/apache-felix-osgi-tutorial/apache-felix-tutorial-example-8.html">Example 8 - Spell Checker Service using Service Binder</a>
   </li>
   <li class="nav-item" data-depth="3">
     <a class="nav-link" href="../tutorials-examples-and-presentations/apache-felix-osgi-tutorial/apache-felix-tutorial-example-9.html">Example 9 - Spell Checker Service using Declarative Services</a>
   </li>
 </ul>
   </li>
 </ul>
   </li>
   <li class="nav-item" data-depth="1">
     <a class="nav-link" href="../license.html">Apache License 2.0</a>
   </li>
   <li class="nav-item" data-depth="1">
     <a class="nav-link" href="../site-map.html">Site map</a>
   </li>
 </ul>
   </li>
 </ul>
   </nav>
 </div>
 <div class="nav-panel-explore" data-panel="explore">
   <div class="context">
     <span class="title">Documentation</span>
     <span class="version">master</span>
   </div>
   <ul class="components">
     <li class="component is-current">
       <span class="title">Documentation</span>
       <ul class="versions">
         <li class="version is-current is-latest">
           <a href="../index.html">master</a>
         </li>
       </ul>
     </li>
   </ul>
 </div>
     </div>
   </aside>
 </div>
 <main class="article">
 <div class="toolbar" role="navigation">
 <button class="nav-toggle"></button>
   <a href="../index.html" class="home-link"></a>
 <nav class="breadcrumbs" aria-label="breadcrumbs">
   <ul>
     <li><a href="../index.html">Documentation</a></li>
     <li><a href="../subprojects.html">Subprojects</a></li>
     <li><a href="apache-felix-metatype-service.html">Apache Felix Metatype Service</a></li>
   </ul>
 </nav>
   <div class="edit-this-page"><a href="https://github.com/apache/felix-antora-site/edit/main/modules/ROOT/pages/subprojects/apache-felix-metatype-service.adoc">Edit this Page</a></div>
   </div>
   <div class="content">
 <article class="doc">
 <h1 class="page">Apache Felix Metatype Service</h1>
 <div id="preamble">
 <div class="sectionbody">
 <div class="paragraph">
 <p>The OSGi Metatype specification provides a unified way to describe metadata about services and a Java interface to retrieve and manipulate such information.
 This information can optionally be localized, thus allowing the developer to provide human-readable metadata descriptions in multiple languages.
 The specification defines a rich dynamic typing system to describe service attributes in a precise way, which makes it possible to dynamically create user interfaces to configure services.</p>
 </div>
 <div class="paragraph">
 <p>The simplest way to specify service metatype information is to add one or more XML files in the <code>OSGI-INF/metatype</code> folder.
 For example, the <code>OSGI-INF/metatype/metatype.xml</code> file included in the <a href="apache-felix-file-install.html" class="page">Apache Felix File Install</a> subproject is as follows:</p>
 </div>
 <div class="listingblock">
 <div class="content">
 <pre>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
 &lt;metatype:MetaData xmlns:metatype="http://www.osgi.org/xmlns/metatype/v1.0.0"&gt;

   &lt;OCD description="FileInstaller" name="org.apache.felix.fileinstall" id="org.apache.felix.fileinstall"&gt;

     &lt;AD name="Poll directory"  id="felix.fileinstall.dir" required="true" type="String" default="load"/&gt;
     &lt;AD name="Poll interval"  id="felix.fileinstall.poll" required="false" type="String" default="5000"/&gt;
     &lt;AD name="Debug"  id="felix.fileinstall.debug" required="false" type="String" default="-1"/&gt;
     &lt;AD name="Start new bundles?"  id="felix.fileinstall.bundles.new.start" required="false" type="String" default="true"/&gt;

   &lt;/OCD&gt;

     &lt;Designate pid="org.apache.felix.fileinstall"&gt;
         &lt;Object ocdref="org.apache.felix.fileinstall"/&gt;
     &lt;/Designate&gt;

 &lt;/metatype:MetaData&gt;</pre>
 </div>
 </div>
 <div class="paragraph">
 <p>The main elements of this simple example are:</p>
 </div>
 <div class="ulist">
 <ul>
 <li>
 <p><em>OCD</em>, Object Class Definition;
 contains the information about a set of attributes.</p>
 </li>
 <li>
 <p><em>AD</em>, Attribute Definition;
 describes an attribute (name, description, unique id, type, cardinality, default value, &#8230;&#8203;).</p>
 </li>
 <li>
 <p><em>Designate</em>, defines the association between an Object Class Definition and a pid;
 the pid can be a reference to a factory or a singleton configuration object.</p>
 </li>
 </ul>
 </div>
 <div class="paragraph">
 <p>The following types are supported by the specification:</p>
 </div>
 <div class="ulist">
 <ul>
 <li>
 <p>String</p>
 </li>
 <li>
 <p>Long</p>
 </li>
 <li>
 <p>Double</p>
 </li>
 <li>
 <p>Float</p>
 </li>
 <li>
 <p>Integer</p>
 </li>
 <li>
 <p>Byte</p>
 </li>
 <li>
 <p>Char</p>
 </li>
 <li>
 <p>Boolean</p>
 </li>
 <li>
 <p>Short</p>
 </li>
 </ul>
 </div>
 </div>
 </div>
 <div class="sect1">
 <h2 id="_localization"><a class="anchor" href="#_localization"></a>Localization</h2>
 <div class="sectionbody">
 <div class="paragraph">
 <p>As mentioned before, it is possible to localize metatype information.
 A good example is the <a href="apache-felix-web-console.html" class="page">Apache Felix Web Console</a> subproject, which includes the following metatype information:</p>
 </div>
 <div class="listingblock">
 <div class="content">
 <pre>&lt;?xml version="1.0" encoding="UTF-8"?&gt;

 &lt;metatype:MetaData xmlns:metatype="http://www.osgi.org/xmlns/metatype/v1.0.0" localization="OSGI-INF/metatype/metatype"&gt;

     &lt;OCD id="org.apache.felix.webconsole.internal.servlet.OsgiManager" name="%manager.name" description="%manager.description"&gt;
         &lt;AD id="manager.root" type="String" default="/system/console" name="%manager.root.name" description="%manager.root.description"/&gt;
         &lt;AD id="default.render" type="String" default="bundles" name="%default.render.name" description="%default.render.description"/&gt;
         &lt;AD id="realm" type="String" default="OSGi Management Console" name="%realm.name" description="%realm.description"/&gt;
         &lt;AD id="username" type="String" default="admin" name="%username.name" description="%username.description"/&gt;
         &lt;AD id="password" type="String" default="admin" name="%password.name" description="%password.description"/&gt;
     &lt;/OCD&gt;

     &lt;Designate pid="org.apache.felix.webconsole.internal.servlet.OsgiManager"&gt;
         &lt;Object ocdref="org.apache.felix.webconsole.internal.servlet.OsgiManager"/&gt;
     &lt;/Designate&gt;

 &lt;/metatype:MetaData&gt;</pre>
 </div>
 </div>
 <div class="paragraph">
 <p>The key elements to write a localized metatype definition are</p>
 </div>
 <div class="ulist">
 <ul>
 <li>
 <p>The <em>localization</em> attribute, that points to the property file that localize this XML.</p>
 </li>
 <li>
 <p>The <em>%</em> notation that specifies a localizable string name.</p>
 </li>
 <li>
 <p>One or more property files defining localized strings.</p>
 </li>
 </ul>
 </div>
 <div class="paragraph">
 <p>The following example shows the localization property file of the Web Console:</p>
 </div>
 <div class="listingblock">
 <div class="content">
 <pre>manager.name = Apache Felix OSGi Management Console
 manager.description = Configuration of the Apache Felix OSGi Management Console.

 manager.root.name = Root URI
 manager.root.description = The root path to the OSGi Management Console.

 realm.name = Realm
 realm.description = The name of the HTTP Authentication Realm.

 username.name = User Name
 username.description = The name of the user allowed to access the OSGi \
  Management Console. To disable authentication clear this value.

 password.name = Password
 password.description = The password for the user allowed to access the OSGi \
  Management Console.

 default.render.name = Default Page
 default.render.description = The name of the default configuration page \
  when invoking the OSGi Management console.</pre>
 </div>
 </div>
 </div>
 </div>
 <div class="sect1">
 <h2 id="_metatype_service_api"><a class="anchor" href="#_metatype_service_api"></a>Metatype Service API</h2>
 <div class="sectionbody">
 <div class="paragraph">
 <p>Before using the Metatype Service API, it&#8217;s worth noting that this specification is not part of the OSGi core specification, so it&#8217;s not included in the standard Felix distribution.
 It is therefore necessary to download and install the additional Metatype bundle.</p>
 </div>
 <div class="paragraph">
 <p>Accessing the Metatype service is as simple as performing a lookup in the service registry:</p>
 </div>
 <div class="literalblock">
 <div class="content">
 <pre>ServiceReference metatypeRef = bundleContext.getServiceReference(MetaTypeService.class.getName());
 MetaTypeService service = (MetaTypeService) bundleContext.getService(metatypeRef);</pre>
 </div>
 </div>
 <div class="literalblock">
 <div class="content">
 <pre>MetaTypeInformation information = service.getMetaTypeInformation(myBundle);</pre>
 </div>
 </div>
 <div class="paragraph">
 <p>After retrieving the <code>MetaTypeInformation</code> object for the required bundle, we have access to all the information contained in the metatype XML definition.
 In particular, it is possible to access the ObjectClassDefinition (optionally specifying a locale):</p>
 </div>
 <div class="literalblock">
 <div class="content">
 <pre>ObjectClassDefinition ocd = information.getObjectClassDefinition(pid, locale);</pre>
 </div>
 </div>
 <div class="paragraph">
 <p>With the <code>ObjectClassDefinition</code>, it is possible to retrieve all the attribute definitions:</p>
 </div>
 <div class="literalblock">
 <div class="content">
 <pre>AttributeDefinition[] attributes = ocd.getAttributeDefinitions(ObjectClassDefinition.ALL);</pre>
 </div>
 </div>
 </div>
 </div>
 </article>
 <aside class="toc sidebar" data-title="Contents" data-levels="2">
   <div class="toc-menu"></div>
 </aside>
   </div>
 </main>
 </div>
 <footer class="footer">
   <p>Content licensed under AL2. UI licensed under MPL-2.0 with extensions licensed under AL2</p>
 </footer>
 <script src="../../_/js/site.js"></script>
 <script async src="../../_/js/vendor/highlight.js"></script>
   </body>
 </html>