1 files changed, 170 insertions, 0 deletions
diff --git a/tags/java/sca/1.5.1/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ServiceDiscovery.java b/tags/java/sca/1.5.1/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ServiceDiscovery.java
new file mode 100644
index 0000000000..a95ab253ae
--- /dev/null
+++ b/tags/java/sca/1.5.1/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ServiceDiscovery.java
@@ -0,0 +1,170 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.    
+ */
+
+package org.apache.tuscany.sca.extensibility;
+
+import java.io.IOException;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * Service discovery for Tuscany based on J2SE Jar service provider spec.
+ * Services are described using configuration files in META-INF/services.
+ * Service description specifies a class name followed by optional properties.
+ * 
+ *
+ * @version $Rev$ $Date$
+ */
+public class ServiceDiscovery {
+    private static final Logger logger = Logger.getLogger(ServiceDiscovery.class.getName());
+
+    private final static ServiceDiscovery INSTANCE = new ServiceDiscovery();
+
+    private ServiceDiscoverer discoverer;
+    private Set<ClassLoader> registeredClassLoaders = new HashSet<ClassLoader>();
+
+    /**
+     * Get an instance of Service discovery, one instance is created per
+     * ClassLoader that this class is loaded from
+     * 
+     * @return
+     */
+    public static ServiceDiscovery getInstance() {
+        return INSTANCE;
+    }
+
+    public ServiceDiscoverer getServiceDiscoverer() {
+        if (discoverer == null) {
+            discoverer = new ClassLoaderServiceDiscoverer();
+        }
+        return discoverer;
+    }
+
+    public void setServiceDiscoverer(ServiceDiscoverer sd) {
+        if (discoverer != null) {
+            throw new IllegalStateException("The ServiceDiscoverer cannot be reset");
+        }
+        discoverer = sd;
+    }
+
+    /**
+     * @deprecated
+     * Register a ClassLoader with this discovery mechanism. Tuscany extension
+     * ClassLoaders are registered here.
+     * 
+     * @param classLoader
+     */
+    @Deprecated
+    public synchronized void registerClassLoader(ClassLoader classLoader) {
+        registeredClassLoaders.add(classLoader);
+    }
+
+    /**
+     * @deprecated
+     * Unregister a ClassLoader with this discovery mechanism. 
+     * 
+     * @param classLoader
+     */
+    @Deprecated
+    public synchronized void unregisterClassLoader(ClassLoader classLoader) {
+        registeredClassLoaders.remove(classLoader);
+    }
+
+    /**
+     * Get all service declarations for this name
+     * 
+     * @param name
+     * @return set of service declarations
+     * @throws IOException
+     */
+    public Set<ServiceDeclaration> getServiceDeclarations(String name) throws IOException {
+        Set<ServiceDeclaration> services = getServiceDiscoverer().discover(name, false);
+        return services;
+    }
+
+    /**
+     * Get all service declarations for this interface
+     * 
+     * @param serviceInterface
+     * @return set of service declarations
+     * @throws IOException
+     */
+    public Set<ServiceDeclaration> getServiceDeclarations(Class<?> serviceInterface) throws IOException {
+
+        return getServiceDeclarations(serviceInterface.getName());
+    }
+
+    /**
+     * Load one service implementation class for this interface
+     * 
+     * @param serviceInterface
+     * @return service implementation class
+     * @throws IOException
+     * @throws ClassNotFoundException
+     */
+    public Class<?> loadFirstServiceClass(final Class<?> serviceInterface) throws IOException, ClassNotFoundException {
+        // Try System property first
+        String className = AccessController.doPrivileged(new PrivilegedAction<String>() {
+            public String run() {
+                return System.getProperty(serviceInterface.getName());
+            }
+        });
+        if (className != null) {
+            try {
+                // Try the classloader for the service interface first 
+                return Class.forName(className, false, serviceInterface.getClassLoader());
+            } catch (ClassNotFoundException e) {
+                try {
+                    // Try the thread context classloader
+                    return Class.forName(className, false, Thread.currentThread().getContextClassLoader());
+                } catch (ClassNotFoundException ex) {
+                    logger.log(Level.WARNING, ex.getMessage(), ex);
+                }
+            }
+        }
+        Set<ServiceDeclaration> services = getServiceDiscoverer().discover(serviceInterface.getName(), true);
+        if (services.isEmpty()) {
+            return null;
+        }
+        return services.iterator().next().loadClass();
+    }
+    
+    /**
+     * Create a new instance of a factory service class.
+     * 
+     * @param serviceInterface
+     * @return service implementation class
+     * @throws SecurityException
+     * @throws NoSuchMethodException
+     * @throws InvocationTargetException
+     * @throws IllegalAccessException
+     */
+    public Object newFactoryClassInstance(final Class<?> serviceInterface) throws SecurityException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {
+        Method newInstanceMethod = serviceInterface.getMethod("newInstance");
+        Object factory = newInstanceMethod.invoke(null);
+        return factory;
+    }
+
+}