Dynamic Server Configuration Service

Description

The Dynamic Server Configuration Service (DSCS) is built around the Basic Configuration Service. The DSCS provides the environment to change specific Sakai properties during run-time using JMX.

Usage

Simple Case 1: Configure a String object

• First we configure the DSCS so that it knows about the property. Define your property as a static string in:
  • org.sakaiproject.component.configuration.properties.api.ConfigurationProperties
  • e.g.

    package org.sakaiproject.component.configuration.properties.api;
    
    	public interface ConfigurationProperties {
    
    		// Person's First Name
    		public static final String PERSON_FIRST_NAME = "org.sakaiproject.example.Person.FirstName";
    
    		// ...
    	}
    	
    

• Now, modify the component-impl's components.xml file.
• Find the following bean: "<bean id="org.sakaiproject.component.configuration.service.api.DynamicServerConfigurationService" and locate the "dynamicSakaiProperties" bean property. Then add your configurable property to the map and assign it an initial value:
  • e.g.

    <property name="dynamicSakaiProperties">
    	<map>
    		<entry key="org.sakaiproject.example.Person.FirstName">
    			<value>Thomas</value>
    		</entry>
    	</map>
    </property>
    

• The target class that wants to add a dynamically configurable property needs to implement "ConfigurationNotificationListener" and "ConfigurationProperties"
  • e.g.

    public class PersonImpl implements ConfigurationNotificationListener, ConfigurationProperties { ... }
    

• The class needs to get the initial property value either at construction time or during a Spring init() method invocation
  • e.g.

    
    package org.sakaiproject.example.Person;
    
    public class PersonImpl implements ConfigurationNotificationListener, ConfigurationProperties {
    
    	// ...
    
    	private String firstName;
    	private DynamicServerConfigurationService dynamicServerConfigurationService;
    	
    	// ...
    
    	// Spring DSCS injection
    	public void setDynamicServerConfigurationService(DynamicServerConfigurationService dynamicServerConfigurationService) {
    		this.dynamicServerConfigurationService = dynamicServerConfigurationService;
    	}
    
    	// Spring init method
    	public void init() {
    		
    		// Configuration Service
    		dynamicServerConfigurationService.addNotificationListener(this, PERSON_FIRST_NAME);
    		
    		try {
    			
    			firstName = dynamicServerConfigurationService.getDynamicString(PERSON_FIRST_NAME);
    			
    		} catch (ConfigurationObjectNotFound e) {
    			LOG.error("Was not able to find configuration property");
    		} catch (InvalidConfigurationKey e) {
    			LOG.error("Provided invalid configuration key");
    		}
    	}
    	
    	// Implementing ConfigurationNotificationListener API: handleNotification
    	public void handleNotification(String configurationItemKey) {
    		
    		try {
    
    			if(PERSON_FIRST_NAME.equals(configurationItemKey)) {
    				firstName = dynamicServerConfigurationService.getDynamicString(PERSON_FIRST_NAME);
    			}
    
    		} catch (ConfigurationObjectNotFound e) {
    			LOG.error("Was not able to find configuration property for key = " + configurationItemKey);
    		} catch (InvalidConfigurationKey e) {
    			LOG.error("Provided invalid configuration key = " + configurationItemKey);
    		}
    	}