| <!DOCTYPE html> |
| <html lang="en"> |
| <head> |
| <meta charset="utf-8"> |
| <meta name="viewport" content="width=device-width,initial-scale=1"> |
| <title>Example 9 - Spell Checker Service using Declarative Services :: Apache Felix</title> |
| <link rel="canonical" href="https://felix.apache.org/documentation/tutorials-examples-and-presentations/apache-felix-osgi-tutorial/apache-felix-tutorial-example-9.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="../../subprojects/apache-felix-dependency-manager.html">Dependency Manager</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-event-admin.html">Event Admin</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-file-install.html">File Install</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-framework.html">Framework</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-gogo.html">Gogo Shell</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-healthchecks.html">Health Checks</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-inventory.html">Inventory</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-log.html">Log</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-logback.html">Logback</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-maven-bundle-plugin.html">Maven bundle plugin</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-maven-scr-plugin.html">Maven SCR plugin</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-metatype-service.html">Metatype Service</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-preferences-service.html">Preferences Service</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-remote-shell.html">Remote Shell</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-script-console-plugin.html">Script console plugin</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-shell.html">Lightweight shell</a> |
| <a class="navbar-item" href="../../subprojects/apache-felix-shell-tui.html">Shell TUI</a> |
| <a class="navbar-item" href="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/apache-felix-dependency-manager/guides/annotations.html">Dependency Manager - Annotations</a> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <a class="nav-link" href="../../subprojects/apache-felix-dependency-manager/guides/background.html">Dependency Manager - Background</a> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <a class="nav-link" href="../../subprojects/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="../../subprojects/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="../../subprojects/apache-felix-dependency-manager/guides/development.html">Dependency Manager - Development</a> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <a class="nav-link" href="../../subprojects/apache-felix-dependency-manager/guides/history.html">Dependency Manager - History</a> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <a class="nav-link" href="../../subprojects/apache-felix-dependency-manager/guides/javadocs.html">Dependency Manager - JavaDocs</a> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <a class="nav-link" href="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/apache-felix-dependency-manager/guides/whatsnew.html">Dependency Manager - What’s new in version 4?</a> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <a class="nav-link" href="../../subprojects/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="../../subprojects/apache-felix-dependency-manager/guides/whatsnew-r15.html">What’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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/apache-felix-dependency-manager/reference/components.html">Dependency Manager - Components</a> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <a class="nav-link" href="../../subprojects/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="../../subprojects/apache-felix-dependency-manager/reference/dependencies.html">Dependency Manager - Dependencies</a> |
| </li> |
| <li class="nav-item" data-depth="4"> |
| <a class="nav-link" href="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/apache-felix-event-admin.html">Apache Felix Event Admin</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../../subprojects/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="../../subprojects/apache-felix-framework.html">Apache Felix Framework</a> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="3"> |
| <a class="nav-link" href="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/apache-felix-gogo.html">Apache Felix Gogo</a> |
| <ul class="nav-list"> |
| <li class="nav-item" data-depth="3"> |
| <a class="nav-link" href="../../subprojects/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="../../subprojects/apache-felix-healthchecks.html">Apache Felix Health Checks</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../../subprojects/apache-felix-inventory.html">Apache Felix Inventory Printer</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../../subprojects/apache-felix-log.html">Apache Felix Log</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../../subprojects/apache-felix-logback.html">Apache Felix Logback</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../../subprojects/apache-felix-maven-bundle-plugin-bnd.html">Apache Felix Maven Bundle Plugin (BND)</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../../subprojects/apache-felix-metatype-service.html">Apache Felix Metatype Service</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../../subprojects/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="../../subprojects/apache-felix-preferences-service.html">Apache Felix Preferences Service</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../../subprojects/apache-felix-remote-shell.html">Apache Felix Remote Shell</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../../subprojects/apache-felix-shell.html">Apache Felix Shell</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../../subprojects/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="../apache-felix-application-demonstration.html">Apache Felix Application Demonstration</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../apache-felix-osgi-tutorial.html">Apache Felix OSGi Tutorial</a> |
| </li> |
| <li class="nav-item" data-depth="2"> |
| <a class="nav-link" href="../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="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="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="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="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="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="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="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="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="apache-felix-tutorial-example-8.html">Example 8 - Spell Checker Service using Service Binder</a> |
| </li> |
| <li class="nav-item is-current-page" data-depth="3"> |
| <a class="nav-link" href="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="../../tutorials-examples-and-presentations.html">Tutorials</a></li> |
| <li>OSGI Tutorial</li> |
| <li><a href="apache-felix-tutorial-example-9.html">Example 9 - Spell Checker Service using Declarative Services</a></li> |
| </ul> |
| </nav> |
| <div class="edit-this-page"><a href="https://github.com/apache/felix-antora-site/edit/main/modules/ROOT/pages/tutorials-examples-and-presentations/apache-felix-osgi-tutorial/apache-felix-tutorial-example-9.adoc">Edit this Page</a></div> |
| </div> |
| <div class="content"> |
| <article class="doc"> |
| <h1 class="page">Example 9 - Spell Checker Service using Declarative Services</h1> |
| <div class="paragraph"> |
| <p>The purpose of this example is to re-implement the spell checker service in Example 6, but to do so using Declarative Service. |
| Therefore you need to install the Declarative Services implementation into your OSGi framework.</p> |
| </div> |
| <div class="paragraph"> |
| <p>The spell checker service of Example 6 was complex because it needed to aggregate all available dictionary services and monitor their dynamic availability. |
| In addition, the spell checker service’s own availability was dependent upon the availability of dictionary services; |
| in other words, the spell checker service had a dynamic, one-to-many dependency on dictionary services. |
| As it turns out, service dependencies are not managed at all by the OSGi framework and end up being the responsibility of the application developer. |
| Declarative Services tries to eliminate complex and error-prone service dependency handling by automating it. |
| To do this, Declarative Services parses XML files in a bundle that describes the components we want to create and their service dependencies. |
| Instead of writing a lot of complex code, we simply use annotations. |
| At build time the tooling creates a declarative XML file which is included in the bundle. |
| There is no need to write an Activator.</p> |
| </div> |
| <div class="paragraph"> |
| <p>We define the new spell checker service in a file called <code>SpellCheckerImpl.java</code> as follows:</p> |
| </div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre>/* |
| * Apache Felix OSGi tutorial. |
| **/ |
| |
| package tutorial.example9; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.StringTokenizer; |
| |
| import org.apache.felix.examples.dictionaryservice.DictionaryService; |
| import org.apache.felix.examples.spellcheckservice.SpellCheckService; |
| import org.osgi.service.component.annotations.Component; |
| import org.osgi.service.component.annotations.Reference; |
| import org.osgi.service.component.annotations.ReferenceCardinality; |
| import org.osgi.service.component.annotations.ReferencePolicy; |
| |
| |
| /** |
| * This class re-implements the spell check service of Example 6. This service |
| * implementation behaves exactly like the one in Example 6, specifically, it |
| * aggregates all available dictionary services, monitors their dynamic |
| * availability, and only offers the spell check service if there are dictionary |
| * services available. The service implementation is greatly simplified, though, |
| * by using the Service Component Runtime. Notice that there is no OSGi references in the |
| * application code; instead, the annotations describe the service |
| * dependencies to the Service Component Runtime, which automatically manages them and it |
| * also automatically registers the spell check services as appropriate. |
| */ |
| @Component |
| public class SpellCheckServiceImpl implements SpellCheckService |
| { |
| /** |
| * List of service objects. |
| * |
| * This field is managed by the Service Component Runtime and updated |
| * with the current set of available dictionary services. |
| * At least one dictionary service is required. |
| */ |
| @Reference(policy=ReferencePolicy.DYNAMIC, cardinality=ReferenceCardinality.AT_LEAST_ONE) |
| private volatile List<DictionaryService> m_svcObjList; |
| |
| /** |
| * Checks a given passage for spelling errors. A passage is any number of |
| * words separated by a space and any of the following punctuation marks: |
| * comma (,), period (.), exclamation mark (!), question mark (?), |
| * semi-colon (;), and colon(:). |
| * |
| * @param passage |
| * the passage to spell check. |
| * @return An array of misspelled words or null if no words are misspelled. |
| */ |
| public String[] check( String passage ) |
| { |
| // No misspelled words for an empty string. |
| if ( ( passage == null ) || ( passage.length() == 0 ) ) |
| { |
| return null; |
| } |
| |
| List<String> errorList = new ArrayList<String>(); |
| |
| // Tokenize the passage using spaces and punctionation. |
| StringTokenizer st = new StringTokenizer( passage, " ,.!?;:" ); |
| |
| // Put the current set of services in a local field |
| // the field m_svcObjList might be modified concurrently |
| final List<DictionaryService> localServices = m_svcObjList; |
| |
| // Loop through each word in the passage. |
| while ( st.hasMoreTokens() ) |
| { |
| String word = st.nextToken(); |
| boolean correct = false; |
| |
| // Check each available dictionary for the current word. |
| for(final DictionaryService dictionary : localServices) { |
| if ( dictionary.checkWord( word ) ) |
| { |
| correct = true; |
| } |
| } |
| |
| // If the word is not correct, then add it |
| // to the incorrect word list. |
| if ( !correct ) |
| { |
| errorList.add( word ); |
| } |
| } |
| |
| // Return null if no words are incorrect. |
| if ( errorList.size() == 0 ) |
| { |
| return null; |
| } |
| |
| // Return the array of incorrect words. |
| return errorList.toArray( new String[errorList.size()] ); |
| } |
| }</pre> |
| </div> |
| </div> |
| <div class="paragraph"> |
| <p>Notice how much simpler this service implementation is when compared to the same service implemented in Example 6. |
| There are no references to OSGi interfaces in our application code and all tricky and complex code dealing with monitoring of services is handled for us.</p> |
| </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> |
