X-Git-Url: http://wamblee.org/gitweb/?a=blobdiff_plain;f=system%2Fgeneral%2Fsrc%2Fmain%2Fjava%2Forg%2Fwamblee%2Fsystem%2FSystemAssembler.java;h=80bab167fa1de1bf7c7c071d14f6ad60e93b627a;hb=b6364aebdb15bb0648e8db2030d8ad793e209af6;hp=9e38a3e1a0a332cf5c47c9433f53ac018b058873;hpb=16504cb35c59542f7817abfe3c852e9fedd870a3;p=utils

diff --git a/system/general/src/main/java/org/wamblee/system/SystemAssembler.java b/system/general/src/main/java/org/wamblee/system/SystemAssembler.java
index 9e38a3e1..80bab167 100644
--- a/system/general/src/main/java/org/wamblee/system/SystemAssembler.java
+++ b/system/general/src/main/java/org/wamblee/system/SystemAssembler.java
@@ -1,6 +1,8 @@
 package org.wamblee.system;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -9,9 +11,8 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 /**
- * Assembler to control multiple subsystems. It makes sure that
- * all dependencies are met and controls the order in which systems
- * are initialized. 
+ * Assembler to control multiple subsystems. It makes sure that all dependencies
+ * are met and controls the order in which systems are initialized.
  */
 public class SystemAssembler {
 
@@ -21,25 +22,57 @@ public class SystemAssembler {
 	private String _context;
 	private SubSystem[] _systems;
 
+	public static RequiredServiceDescriptor[] filterRequiredServices(
+			ProvidedServiceDescriptor aProvided,
+			Collection<RequiredServiceDescriptor> aDescriptors) {
+		List<RequiredServiceDescriptor> required = new ArrayList<RequiredServiceDescriptor>();
+		for (RequiredServiceDescriptor descriptor : aDescriptors) {
+			if (descriptor.implementedBy(aProvided)) {
+				required.add(descriptor);
+			}
+		}
+		return required.toArray(new RequiredServiceDescriptor[0]);
+	}
+
+	public static ProvidedServiceDescriptor[] filterProvidedServices(
+			RequiredServiceDescriptor aRequired,
+			Collection<ProvidedServiceDescriptor> aProvided) {
+		List<ProvidedServiceDescriptor> provided = new ArrayList<ProvidedServiceDescriptor>();
+		for (ProvidedServiceDescriptor descriptor : aProvided) {
+			if (aRequired.implementedBy(descriptor)) {
+				provided.add(descriptor);
+			}
+		}
+		return provided.toArray(new ProvidedServiceDescriptor[0]);
+	}
+
 	/**
-	 * Constructs the assembler. 
-	 * @param aSystems Systems that must be assembled.
-	 * @param aAvailableServices Available services from other systems
-	 *  outside of the systems that this assembler manages.
+	 * Constructs the assembler.
+	 * 
+	 * @param aSystems
+	 *            Systems that must be assembled.
+	 * @param aAvailableServices
+	 *            Available services from other systems outside of the systems
+	 *            that this assembler manages.
 	 */
-	public SystemAssembler(SubSystem[] aSystems, ServiceDescriptor[] aAvailableServices) {
+	public SystemAssembler(SubSystem[] aSystems,
+			ProvidedServiceDescriptor[] aAvailableServices) {
 		this(ROOT_CONTEXT_NAME, aSystems, aAvailableServices);
 	}
 
 	/**
-	 * Constructs the assembler. 
-	 * @param aContext Context (unique name) of the assembler. 
-	 * @param aSystems Systems that must be assembled. 
-	 * @param aAvailableServices Available services from other systems
-	 *  outside of the systems that this assembler manages.
+	 * Constructs the assembler.
+	 * 
+	 * @param aContext
+	 *            Context (unique name) of the assembler.
+	 * @param aSystems
+	 *            Systems that must be assembled.
+	 * @param aAvailableServices
+	 *            Available services from other systems outside of the systems
+	 *            that this assembler manages.
 	 */
-	public SystemAssembler(String aContext, SubSystem[] aSystems, 
-			ServiceDescriptor[] aAvailableServices) {
+	public SystemAssembler(String aContext, SubSystem[] aSystems,
+			ProvidedServiceDescriptor[] aAvailableServices) {
 		_context = aContext;
 		_systems = aSystems;
 		validate(aAvailableServices);
@@ -49,18 +82,23 @@ public class SystemAssembler {
 	 * Determines if the systems are ordered appropriately so that all
 	 * dependencies are met.
 	 */
-	private void validate(ServiceDescriptor[] aDescriptors) throws SystemAssemblyException {
+	private void validate(ProvidedServiceDescriptor[] aDescriptors)
+			throws SystemAssemblyException {
 
-		List<ServiceDescriptor> allProvided = new ArrayList<ServiceDescriptor>();
-		for (ServiceDescriptor descriptor: aDescriptors) { 
+		List<ProvidedServiceDescriptor> allProvided = new ArrayList<ProvidedServiceDescriptor>();
+		for (ProvidedServiceDescriptor descriptor : aDescriptors) {
 			allProvided.add(descriptor);
 		}
 		for (SubSystem system : _systems) {
 			// Check if all required services are already provided by earlier
 			// systems.
-			ServiceDescriptor[] required = system.getRequiredServices();
-			for (ServiceDescriptor descriptor : required) {
-				if (!(allProvided.contains(descriptor))) {
+			RequiredServiceDescriptor[] required = system.getRequiredServices();
+
+			for (RequiredServiceDescriptor descriptor : required) {
+				ProvidedServiceDescriptor[] filtered = filterProvidedServices(
+						descriptor, allProvided);
+
+				if (filtered.length == 0) {
 					throw new SystemAssemblyException(
 							"Service '"
 									+ descriptor
@@ -68,42 +106,57 @@ public class SystemAssembler {
 									+ system
 									+ "' is not provided by systems that are started earlier");
 				}
+				if (filtered.length > 1) {
+					throw new SystemAssemblyException(
+							"Service '"
+									+ descriptor
+									+ "' required by system '"
+									+ system
+									+ "' matches multiple services provided by other systems: " + 
+									Arrays.asList(filtered));
+				}
 			}
 
 			// add all provided services
-			ServiceDescriptor[] provided = system.getProvidedServices();
-			for (ServiceDescriptor descriptor : provided) {
-				allProvided.add(descriptor);
-			}
+			ProvidedServiceDescriptor[] provided = system.getProvidedServices();
+			allProvided.addAll(Arrays.asList(provided));
 		}
 	}
 
 	/**
 	 * Starts the subsystems.
-	 * @param aRegistry Service registry to which created services must be registered. 
-	 * @param aRequiredServices Services that are available from
-	 *  other systems that have been started before. 
+	 * 
+	 * @param aRegistry
+	 *            Service registry to which created services must be registered.
+	 * @param aRequiredServices
+	 *            Services that are available from other systems that have been
+	 *            started before.
 	 */
 	public void start(ServiceRegistry aRegistry, Service[] aRequiredServices) {
 		LOG.info("Starting '" + _context + "'");
-		Map<ServiceDescriptor, Service> allProvided = new HashMap<ServiceDescriptor, Service>();
+		Map<ProvidedServiceDescriptor, Service> allProvided = new HashMap<ProvidedServiceDescriptor, Service>();
 
 		for (Service service : aRequiredServices) {
 			allProvided.put(service.getDescriptor(), service);
 		}
 		for (SubSystem system : _systems) {
-			ServiceDescriptor[] descriptors = system.getRequiredServices();
+			
+			// Compose a list of the required services required for the subsystem.
+			
+			RequiredServiceDescriptor[] descriptors = system
+					.getRequiredServices();
 			List<Service> services = new ArrayList<Service>();
-			for (ServiceDescriptor descriptor : descriptors) {
-				Service required = allProvided.get(descriptor);
-				if (required == null) {
-					throw new SystemAssemblyException("Service '" + descriptor
-							+ "' required by '" + system + "' is null.");
-				}
-				services.add(required);
+			for (RequiredServiceDescriptor descriptor : descriptors) {
+				ProvidedServiceDescriptor[] provided = filterProvidedServices(
+						descriptor, allProvided.keySet());
+				services.add(allProvided.get(provided[0]));
 			}
+			
+			// Start the service. 
 			Service[] provided = system.start(_context, services
 					.toArray(new Service[0]));
+			
+			// Add started services to the map of started services.
 			for (Service service : provided) {
 				allProvided.put(service.getDescriptor(), service);
 			}