Added uxloader into default build. Solved issues with services not being

available. Will refactor these out into a common module some time soon
(at least before I write another component, ;)).

slingtests/osgikernel/app-bundles/pom.xml

@@ -81,6 +81,11 @@
       <artifactId>org.sakaiproject.kernel2.osgi.db</artifactId>
       <version>0.1-SNAPSHOT</version>
     </dependency>
+    <dependency>
+      <groupId>org.sakaiproject.kernel2.osgi</groupId>
+      <artifactId>org.sakaiproject.kernel2.osgi.uxloader</artifactId>
+      <version>0.1-SNAPSHOT</version>
+    </dependency>
     <dependency>
       <groupId>org.sakaiproject.kernel2.osgi</groupId>
       <artifactId>org.sakaiproject.kernel2.osgi.utils</artifactId>

slingtests/osgikernel/bundles/kernel/src/main/java/org/sakaiproject/kernel/api/configuration/StubConfigurationServiceImpl.java

@@ -40,6 +40,13 @@
 import java.util.Map;
 import java.util.Properties;
 
+/* XXX PROBLEM. I've renamed this the StubConfigurationServiceImpl from KernelConstants. It does contain
+ * some kernel constants, but also is a stub configuration service. Really, the kernel constants should
+ * be moved into a separate file, for things like annotations, etc, to use. However, I'm not sure I
+ * understand what the scr plugin is doing here enough, yet, to do that refactor. This is something which
+ * is high on my todo-list. -- dan
+ */
+
 /**
  * Holds the configuration properties that are used in the kernel. This is an OSGi Managed
  * service that collects together all the configuation properties.

slingtests/osgikernel/bundles/uxloader/pom.xml

@@ -35,11 +35,8 @@
           <instructions>
             <Bundle-Category> sakaiux </Bundle-Category>
             <Bundle-Activator> org.sakaiproject.kernel2.uxloader.Activator </Bundle-Activator>
-            <Export-Package>
-                            <!-- Nothing to Export -->
-            </Export-Package>
+            <Export-Package>org.sakaiproject.kernel2.uxloader</Export-Package>
             <Import-Package> * </Import-Package>
-            <Private-Package>org.sakaiproject.kernel2.uxloader</Private-Package>
             <Embed-Transitive>true</Embed-Transitive>
             <Embed-Dependency>
             </Embed-Dependency>

slingtests/osgikernel/bundles/uxloader/src/main/java/org/sakaiproject/kernel2/uxloader/ActivationProcess.java

@@ -18,12 +18,12 @@ public class ActivationProcess {
 
 	private HttpService http;
 	private HttpContext context;
-	private CacheManagerService cache;
+	private ServiceResolver resolver;
 
-	public ActivationProcess(HttpService http,CacheManagerService cache) {
+	public ActivationProcess(ServiceResolver resolver,HttpService http) {
 		this.http=http;
 		this.context=http.createDefaultHttpContext();
-		this.cache=cache;
+		this.resolver=resolver;
 	}
 
 	public void map(String url,String filesystem) throws ServletException, NamespaceException {
@@ -32,6 +32,6 @@ public void map(String url,String filesystem) throws ServletException, Namespace
         uxLoaderParams.put(FileServlet.BASE_FILE,filesystem);
         uxLoaderParams.put(FileServlet.MAX_CACHE_SIZE, "102400");
         uxLoaderParams.put(FileServlet.WELCOME_FILE, "index.html");
-        http.registerServlet(url, new FileServlet(cache),uxLoaderParams,context);
+        http.registerServlet(url,new FileServlet(resolver),uxLoaderParams,context);
 	}
 }

slingtests/osgikernel/bundles/uxloader/src/main/java/org/sakaiproject/kernel2/uxloader/Activator.java

@@ -42,6 +42,12 @@
  */
 
 public class Activator extends SimpleBaseActivator implements BundleActivator {	
+
+	public Activator() {
+		registerStartupService(ConfigurationService.class);
+		registerStartupService(HttpService.class);
+	}
+
 	private URLFileMapping[] createMapping(String raw) {
 		logger.info("raw ux config is "+raw);
 		List<URLFileMapping> out=new ArrayList<URLFileMapping>();
@@ -65,9 +71,8 @@ private List<URLFileMapping> loadMappings(BundleContext bc,ConfigurationService
 
 	public void go(BundleContext bc) throws Exception {
 		HttpService http=(HttpService)getService(bc,HttpService.class);
-		CacheManagerService cache=(CacheManagerService)getService(bc,CacheManagerService.class);
 		ConfigurationService config=(ConfigurationService)getService(bc,ConfigurationService.class);
-		ActivationProcess activation=new ActivationProcess(http,cache);
+		ActivationProcess activation=new ActivationProcess(new ServiceResolver(bc),http);
 		for(URLFileMapping m : loadMappings(bc,config))
 			activation.map(m.getURL(),m.getFileSystem());
 	}

slingtests/osgikernel/bundles/uxloader/src/main/java/org/sakaiproject/kernel2/uxloader/FileServlet.java

@@ -62,15 +62,14 @@ public class FileServlet extends HttpServlet {
   private File baseFile;
   private Map<String, String> mimeTypes;
   private String welcomeFile;
-  private Cache<FileCache> cache;
   private long maxCacheSize;
-
+  private ServiceResolver resolver;
 
   /**
    * @param cacheManagerService
    */
-  public FileServlet(CacheManagerService cacheManagerService) {
-    cache = cacheManagerService.getCache("file-servlet-cache", CacheScope.INSTANCE);
+  public FileServlet(ServiceResolver resolver) {
+    this.resolver=resolver;
   }
 
   private void loadMIMETypesFromFile() throws IOException {
@@ -157,10 +156,14 @@ protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws Se
 		  return;
 	  }
 	  logger.debug("Sending "+to_send.getAbsolutePath());
+	  try {
 	  if(to_send.isDirectory())
 		  sendDirectory(to_send,resp);
 	  else
 		  sendFile(to_send,resp);
+	  } catch(ServiceDisappearedException x) {
+		  throw new ServletException("No service available",x);
+	  }
   }
 
   private void sendDirectory(File f, HttpServletResponse resp) throws IOException {
@@ -184,7 +187,7 @@ private boolean candidateForCache(File file) {
 	  return file.length() < maxCacheSize;
   } 
 
-  private FileCache getNonExpiredFileCache(File file) {
+  private FileCache getNonExpiredFileCache(Cache<FileCache> cache,File file) {
 	  if(!candidateForCache(file))
 		  return null;
 	  String path = file.getAbsolutePath();
@@ -196,14 +199,16 @@ private FileCache getNonExpiredFileCache(File file) {
 	  return fc;
   }
 
-  private void sendFile(File file, HttpServletResponse resp) throws IOException {
+  private void sendFile(File file, HttpServletResponse resp) throws IOException, ServiceDisappearedException {
+	  CacheManagerService cache_service=(CacheManagerService)resolver.getService(CacheManagerService.class);
+	  Cache<FileCache> cache=cache_service.getCache("file-servlet-cache", CacheScope.INSTANCE);
 	  if(!file.exists()) {
 		  resp.sendError(HttpServletResponse.SC_NOT_FOUND);
 		  return;
 	  }	  
 	  if(candidateForCache(file)) {
 		  // Cacheable
-		  FileCache cache_entry=getNonExpiredFileCache(file);
+		  FileCache cache_entry=getNonExpiredFileCache(cache,file);
 		  if(cache_entry==null) {
 			  cache_entry = new FileCache(file,getContentTypeFromExtension(file));
 			  cache.put(file.getAbsolutePath(),cache_entry);

slingtests/osgikernel/bundles/uxloader/src/main/java/org/sakaiproject/kernel2/uxloader/ServiceDisappearedException.java

@@ -0,0 +1,19 @@
+package org.sakaiproject.kernel2.uxloader;
+
+public class ServiceDisappearedException extends Exception {
+	public ServiceDisappearedException() {
+		super();
+	}
+
+	public ServiceDisappearedException(String message, Throwable cause) {
+		super(message, cause);
+	}
+
+	public ServiceDisappearedException(String message) {
+		super(message);
+	}
+
+	public ServiceDisappearedException(Throwable cause) {
+		super(cause);
+	}
+}

slingtests/osgikernel/bundles/uxloader/src/main/java/org/sakaiproject/kernel2/uxloader/ServiceResolver.java

@@ -0,0 +1,26 @@
+package org.sakaiproject.kernel2.uxloader;
+
+import org.osgi.framework.BundleContext;
+import org.osgi.framework.ServiceReference;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class ServiceResolver {
+	protected static final Logger logger = LoggerFactory.getLogger(ServiceResolver.class);
+
+	private BundleContext bc;
+
+	public ServiceResolver(BundleContext bc) { this.bc=bc; }
+
+	public Object getService(Class klass) throws ServiceDisappearedException {
+		ServiceReference ref=bc.getServiceReference(klass.getName());
+	    if(ref==null) {
+	    	logger.warn("Service disappeared: "+klass.getCanonicalName());
+	    	throw new ServiceDisappearedException("Service disappeared: "+klass.getCanonicalName());
+	    }
+	    Object out=bc.getService(ref);
+	    logger.info("Got "+out);
+	    return out;
+
+	}
+}

slingtests/osgikernel/bundles/uxloader/src/main/java/org/sakaiproject/kernel2/uxloader/SimpleBaseActivator.java

@@ -1,6 +1,8 @@
 package org.sakaiproject.kernel2.uxloader;
 
+import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import org.osgi.framework.BundleActivator;
@@ -11,10 +13,55 @@
 import org.slf4j.LoggerFactory;
 
 public abstract class SimpleBaseActivator implements BundleActivator {
+	protected static final Logger logger = LoggerFactory.getLogger(Activator.class);	
+
+	private class GoInvoker implements Runnable {
+		private BundleContext bc;
+		private Class<?> outer;
+
+		private GoInvoker(Class<?> outer,BundleContext bc) {
+			this.bc=bc;
+			this.outer=outer;
+		}
+
+		private boolean is_good() {
+			for(Class<?> svc : startup_services) {
+				Object out=getService(bc,svc);
+				if(out==null) {
+					logger.info("Cannot start yet : "+svc.getCanonicalName());
+					return false;
+				}
+			}
+			logger.info("All services ready");
+			return true;
+		}
+
+		public synchronized void run() {
+			int f1=1000,f2=1000;
+
+			try {
+				while(!is_good()) {
+					Thread.sleep(f1);
+					// Fibionacci backoff: exponential with base of golden-mean: slower than 2.
+					int t=f1+f2;
+					f1=f2;
+					f2=t;
+				}
+				go(bc);
+			} catch (Exception x) {
+				logger.error("Could not start service ",x);
+			}
+		}
+
+	}
+
 	private Map<Class<?>,ServiceReference> services=new HashMap<Class<?>,ServiceReference>();
 	private Map<Class<?>,ServiceReference[]> mservices=new HashMap<Class<?>,ServiceReference[]>();
-	protected static final Logger logger = LoggerFactory.getLogger(Activator.class);
-
+	private List<Class<?>> startup_services=new ArrayList<Class<?>>();
+
+	protected void registerStartupService(Class svc) {
+		startup_services.add(svc);
+	}
 
 	public abstract void go(BundleContext bc) throws Exception;
 
@@ -25,11 +72,15 @@ protected Object getService(BundleContext bc,Class<?> klass) {
 	    	ref=bc.getServiceReference(klass.getName());
 	    	services.put(klass,ref);
 	    }
+	    if(ref==null) {
+	    	logger.error("Cannot find service for "+klass.getName());
+	    	return null;
+	    }
 	    Object out=bc.getService(ref);
 	    logger.info("Got "+out);
 	    return out;
 	}
-
+	
 	protected Object[] getServices(BundleContext bc,Class<?> klass) throws InvalidSyntaxException {
 	    ServiceReference[] refs=mservices.get(klass);
 	    if(refs==null) {
@@ -45,7 +96,8 @@ protected Object[] getServices(BundleContext bc,Class<?> klass) throws InvalidSy
 	}
 
 	public void start(BundleContext bc) throws Exception {
-		go(bc);
+		Thread t=new Thread(new GoInvoker(this.getClass(),bc));
+		t.start();
 	}
 
 	public void stop(BundleContext bc) throws Exception {

slingtests/osgikernel/pom.xml

@@ -40,6 +40,7 @@
         <module>bundles/db</module>
         <module>bundles/kernel</module>
         <module>bundles/memory</module>
+        <module>bundles/uxloader</module>
         <module>libraries/utils</module>
       </modules>
     </profile>