add file storage management service

java/com.sap.sse.filestorage/META-INF/MANIFEST.MF

@@ -8,7 +8,8 @@ Bundle-RequiredExecutionEnvironment: JavaSE-1.8
 Export-Package: com.sap.sse.filestorage,
  com.sap.sse.filestorage.impl,
  com.sap.sse.filestorage.testsupport
-Import-Package: org.osgi.framework;version="1.8.0"
+Import-Package: com.sap.sse.osgi,
+ org.osgi.framework;version="1.8.0"
 Bundle-Activator: com.sap.sse.filestorage.impl.Activator
 Require-Bundle: org.apache.servicemix.bundles.aws-java-sdk;bundle-version="1.9.8",
  com.fasterxml.jackson.core.jackson-databind,

java/com.sap.sse.filestorage/src/com/sap/sse/filestorage/FileStorageManagementService.java

@@ -0,0 +1,36 @@
+package com.sap.sse.filestorage;
+
+import com.sap.sse.common.NoCorrespondingServiceRegisteredException;
+
+/**
+ * OSGi service for managing {@link FileStorageService FileStorageServices}.
+ * 
+ * @author Fredrik Teschke
+ *
+ */
+public interface FileStorageManagementService {
+    FileStorageService[] getAvailableFileStorageServices();
+    
+    FileStorageService getFileStorageService(String name);
+
+    /**
+     * Sets the property of the service, and also stores the property value so that it can be restored
+     * after a server restart.
+     * @throws NoCorrespondingServiceRegisteredException service may have disappeared from registry in the meantime
+     * @throws IllegalArgumentException if the property with name {@code propertyName} doesn't exist for the service
+     */
+    void setFileStorageServiceProperty(String serviceName, String propertyName, String propertyValue)
+            throws NoCorrespondingServiceRegisteredException, IllegalArgumentException;
+    
+    /**
+     * @return may be {@code null} if no service has been selected so far.
+     */
+    FileStorageService getActiveFileStorageService();
+
+    /**
+     * @throws InvalidPropertiesException
+     *             if the service properties are {@link FileStorageService#testProperties() invalid}. Then the old
+     *             active service (if any) remains active.
+     */
+    void setActiveFileStorageService(FileStorageService service) throws InvalidPropertiesException;
+}

java/com.sap.sse.filestorage/src/com/sap/sse/filestorage/FileStorageService.java

@@ -4,11 +4,13 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.net.URI;
 
+import com.sap.sse.common.TypeBasedServiceFinder;
+
 /**
  * Service for storing files. The interface is intentionally agnostic of the underlying implementation, which may be
  * provided e.g. by using Amazon's S3 or simply saving the files to a statically reachable directory on one of our
  * servers. Implementations of this service are announced via the OSGi service registry. They should provide their name
- * as the OSGi property "name";
+ * as the OSGi property {@link TypeBasedServiceFinder#TYPE type};
  * 
  * TODO The storage service to use should be configured via the AdminConsole. Upon auto-discovering the available
  * services, the AdminConsole should allow to edit properties for each service (e.g. access credentials for AWS S3). We
@@ -34,6 +36,8 @@ public interface FileStorageService {
     Property[] getProperties();
 
     /**
+     * Should not be called directly, but through {@link FileStorageManagementService#setFileStorageServiceProperty}
+     * as this deals with storing the new values.
      * @throws IllegalArgumentException
      *             if {@code name} is not a valid property name
      */

java/com.sap.sse.filestorage/src/com/sap/sse/filestorage/impl/Activator.java

@@ -1,15 +1,30 @@
 package com.sap.sse.filestorage.impl;
 
+import java.util.Dictionary;
+import java.util.Hashtable;
+
 import org.osgi.framework.BundleActivator;
 import org.osgi.framework.BundleContext;
 
+import com.sap.sse.common.TypeBasedServiceFinder;
+import com.sap.sse.filestorage.FileStorageManagementService;
 import com.sap.sse.filestorage.FileStorageService;
 
 public class Activator implements BundleActivator {
 
     @Override
     public void start(BundleContext context) throws Exception {
-        context.registerService(FileStorageService.class, new AmazonS3FileStorageServiceImpl(), null);        
+        Dictionary<String, String> dict = new Hashtable<>();
+        dict.put(TypeBasedServiceFinder.TYPE, AmazonS3FileStorageServiceImpl.NAME);
+        context.registerService(FileStorageService.class, new AmazonS3FileStorageServiceImpl(), dict);
+
+        TransientFileStorageManagementServiceImpl mgmtService = new TransientFileStorageManagementServiceImpl();
+        context.registerService(FileStorageManagementService.class, mgmtService,
+                null);
+        mgmtService.setContext(context);
+        
+
+        //TODO load service properties from DB on startup
     }
 
     @Override

java/com.sap.sse.filestorage/src/com/sap/sse/filestorage/impl/AmazonS3FileStorageServiceImpl.java

@@ -35,6 +35,7 @@ import com.sap.sse.filestorage.Property;
  *
  */
 public class AmazonS3FileStorageServiceImpl implements FileStorageService {
+    public static final String NAME = "Amazon S3";
     private static final Logger logger = Logger.getLogger(AmazonS3FileStorageServiceImpl.class.getName());
 
     private static final String baseUrl = "s3.amazonaws.com";
@@ -144,7 +145,7 @@ public class AmazonS3FileStorageServiceImpl implements FileStorageService {
 
     @Override
     public String getName() {
-        return "Amazon S3";
+        return NAME;
     }
 
     @Override

java/com.sap.sse.filestorage/src/com/sap/sse/filestorage/impl/TransientFileStorageManagementServiceImpl.java

@@ -0,0 +1,48 @@
+package com.sap.sse.filestorage.impl;
+
+import org.osgi.framework.BundleContext;
+
+import com.sap.sse.common.NoCorrespondingServiceRegisteredException;
+import com.sap.sse.common.TypeBasedServiceFinder;
+import com.sap.sse.filestorage.FileStorageManagementService;
+import com.sap.sse.filestorage.FileStorageService;
+import com.sap.sse.filestorage.InvalidPropertiesException;
+import com.sap.sse.osgi.CachedOsgiTypeBasedServiceFinderFactory;
+
+public class TransientFileStorageManagementServiceImpl implements FileStorageManagementService {
+    private FileStorageService active;
+
+    private TypeBasedServiceFinder<FileStorageService> serviceFinder;
+
+    public void setContext(BundleContext context) {
+        serviceFinder = new CachedOsgiTypeBasedServiceFinderFactory(context)
+                .createServiceFinder(FileStorageService.class);
+    }
+
+    @Override
+    public FileStorageService getActiveFileStorageService() {
+        return active;
+    }
+
+    @Override
+    public void setActiveFileStorageService(FileStorageService service) throws InvalidPropertiesException {
+        active = service;
+    }
+
+    @Override
+    public FileStorageService[] getAvailableFileStorageServices() {
+        return serviceFinder.findAllServices().toArray(new FileStorageService[0]);
+    }
+
+    @Override
+    public FileStorageService getFileStorageService(String name) {
+        return serviceFinder.findService(name);
+    }
+
+    @Override
+    public void setFileStorageServiceProperty(String serviceName, String propertyName, String propertyValue)
+            throws NoCorrespondingServiceRegisteredException, IllegalArgumentException {
+        //TODO mgmt service that persists properties on master
+        serviceFinder.findService(serviceName).setProperty(propertyName, propertyValue);
+    }
+}