1 files changed, 98 insertions, 0 deletions
diff --git a/sandbox/SPI/implementation-spi-impl/src/main/java/org/apache/tuscany/spi/implementation/impl/Discovery.java b/sandbox/SPI/implementation-spi-impl/src/main/java/org/apache/tuscany/spi/implementation/impl/Discovery.java
new file mode 100644
index 0000000000..ba3392795a
--- /dev/null
+++ b/sandbox/SPI/implementation-spi-impl/src/main/java/org/apache/tuscany/spi/implementation/impl/Discovery.java
@@ -0,0 +1,98 @@
+/*
+ * 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.spi.implementation.impl;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Enumeration;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import org.apache.tuscany.core.util.IOHelper;
+
+public class Discovery {
+
+    /**
+     * Read the service name from a configuration file
+     * 
+     * @param classLoader
+     * @param name The name of the service class
+     * @return A class name which extends/implements the service class
+     * @throws IOException
+     */
+    private static Set<String> getServiceNames(ClassLoader classLoader, String name) throws IOException {
+        Set<String> set = new HashSet<String>();
+        Enumeration<URL> urls = classLoader.getResources("META-INF/services/" + name);
+        while (urls.hasMoreElements()) {
+            URL url = urls.nextElement();
+            Set<String> service = getServiceNames(url);
+            if (service != null) {
+                set.addAll(service);
+
+            }
+        }
+        return set;
+    }
+
+    private static Set<String> getServiceNames(URL url) throws IOException {
+        Set<String> names = new HashSet<String>();
+        InputStream is = IOHelper.getInputStream(url);
+        BufferedReader reader = null;
+        try {
+            reader = new BufferedReader(new InputStreamReader(is));
+            while (true) {
+                String line = reader.readLine();
+                if (line == null) {
+                    break;
+                }
+                line = line.trim();
+                if (!line.startsWith("#") && !"".equals(line)) {
+                    names.add(line.trim());
+                }
+            }
+        } finally {
+            if (reader != null) {
+                reader.close();
+            }
+        }
+        return names;
+    }
+
+    public static <T> Collection<T> getInstances(final ClassLoader classLoader, Class<T> serviceClass) {
+        List<T> instances = new ArrayList<T>();
+        try {
+            Set<String> services = getServiceNames(classLoader, serviceClass.getName());
+            for (String className : services) {
+                Class cls = Class.forName(className, true, classLoader);
+                instances.add(serviceClass.cast(cls.newInstance())); // NOPMD
+            }
+        } catch (Exception e) {
+            throw new IllegalStateException(e);
+        }
+        return instances;
+    }
+
+}