ConfigurationAdmin – Access OSGi configuration of other services

In this article we will explore ConfigurationAdmin interface. Service for administering configuration data.

ConfigurationAdmin is a dictionary of properties. To identify a target service’s dictionary use its PID.

Sharing as code snippet that reads “rootmapping.target” configuration of the OOTB “Day CQ Root Mapping” service.

      
        package com.techrevel.dam.core.servlets;
      
        import java.io.IOException;
      
        import java.util.Dictionary;
      
        import javax.servlet.Servlet;
      
        import org.apache.sling.api.SlingHttpServletRequest;
      
        import org.apache.sling.api.SlingHttpServletResponse;
      
        import org.apache.sling.api.servlets.HttpConstants;
      
        import org.apache.sling.api.servlets.SlingAllMethodsServlet;
      
        import org.apache.sling.commons.osgi.PropertiesUtil;
      
        import org.osgi.service.cm.Configuration;
      
        import org.osgi.service.cm.ConfigurationAdmin;
      
        import org.osgi.service.component.annotations.Component;
      
        import org.osgi.service.component.annotations.Reference;
      
        import org.slf4j.Logger;
      
        import org.slf4j.LoggerFactory;
      
        @Component(service = Servlet.class, property = { "sling.servlet.methods=" + HttpConstants.METHOD_GET,
      
                "sling.servlet.paths=" + "/apps/techrevel/accessserviceconfig" })
      
        public class AccessServiceConfig extends SlingAllMethodsServlet {
      
            private final Logger LOGGER = LoggerFactory.getLogger(getClass());
      
            @Reference
      
            private ConfigurationAdmin configAdmin;
      
            /**
      
             * The method fetches the Post Process Observation configuration
      
             * 
      
             * @throws IOException
      
             */
      
            private void getConfigs() throws IOException {
      
                Configuration taxonomyFeedConfig = configAdmin
      
                        .getConfiguration("com.day.cq.commons.servlets.RootMappingServlet");
      
                Dictionary<String, Object> properties = taxonomyFeedConfig.getProperties();
      
                LOGGER.debug("[getConfigs] – Root Mapping Target: {}",
      
                        PropertiesUtil.toString(properties.get("rootmapping.target"), ""));
      
            }
      
            @Override
      
            protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response) throws IOException {
      
                getConfigs();
      
            }
      
        }

view raw AccessServiceConfig.java hosted with ❤ by GitHub

When a target service’s configuration is updated, config details would also refresh in ConfigurationAdmin API. Thus, if you read configuration once updates are persisted, you would get the updated values. Example: if we access above servlet after updating the “rootmapping.target”, we would receive the updated value in logs.

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