1 files changed, 184 insertions, 0 deletions
diff --git a/tags/java/sca/1.5.1-RC4/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java b/tags/java/sca/1.5.1-RC4/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java
new file mode 100644
index 0000000000..6f7c83c8d9
--- /dev/null
+++ b/tags/java/sca/1.5.1-RC4/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java
@@ -0,0 +1,184 @@
+/*
+ * 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.core;
+
+import java.io.IOException;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Modifier;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.tuscany.sca.extensibility.ServiceDiscovery;
+
+/**
+ * Default implementation of an extension point to hold Tuscany utility utilities.
+ *
+ * @version $Rev$ $Date$
+ */
+public class DefaultUtilityExtensionPoint implements UtilityExtensionPoint {
+    private Map<Class<?>, Object> utilities = new HashMap<Class<?>, Object>();
+    
+    private ExtensionPointRegistry extensionPoints;
+    
+    /**
+     * Constructs a new extension point. 
+     */
+    public DefaultUtilityExtensionPoint(ExtensionPointRegistry extensionPoints) {
+        this.extensionPoints = extensionPoints;
+    }
+
+    /**
+     * Add a utility to the extension point. This default implementation
+     * stores utilities against the interfaces that they implement.
+     *
+     * @param utility The instance of the utility
+     *
+     * @throws IllegalArgumentException if utility is null
+     */
+    public void addUtility(Object utility) {
+        if (utility == null) {
+            throw new IllegalArgumentException("Cannot register null as a Service");
+        }
+
+        Set<Class<?>> interfaces = getAllInterfaces(utility.getClass());
+        for (Class<?> i : interfaces) {
+            utilities.put(i, utility);
+        }
+    }
+    
+    private Constructor<?> getConstructor(Constructor<?>[] constructors, Class<?>[] paramTypes) {
+        for (Constructor<?> c : constructors) {
+            Class<?>[] types = c.getParameterTypes();
+            if (c.getParameterTypes().length == paramTypes.length) {
+                boolean found = true;
+                for (int i = 0; i < types.length; i++) {
+                    if (types[i] != paramTypes[i]) {
+                        found = false;
+                        break;
+                    }
+                }
+                if (found) {
+                    return c;
+                }
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Get the utility by the interface that it implements
+     *
+     * @param utilityType The lookup key (utility interface)
+     * @return The instance of the utility
+     *
+     * @throws IllegalArgumentException if utilityType is null
+     */
+    public <T> T getUtility(Class<T> utilityType) {
+        if (utilityType == null) {
+            throw new IllegalArgumentException("Cannot lookup Service of type null");
+        }
+
+        Object utility = utilities.get(utilityType);
+        if (utility == null) {
+            
+            // Dynamically load a utility class declared under META-INF/utilities           
+            try {
+                Class<?> utilityClass = 
+                	ServiceDiscovery.getInstance().loadFirstServiceClass(utilityType);
+                if (utilityClass != null) {
+                    // Construct the utility
+                    Constructor<?>[] constructors = utilityClass.getConstructors();
+                    Constructor<?> constructor = getConstructor(constructors, new Class<?>[] {ExtensionPointRegistry.class});
+                    if (constructor != null) {
+                        utility = constructor.newInstance(extensionPoints);
+                    } else {
+                        constructor = getConstructor(constructors, new Class<?>[] {});
+                        if (constructor != null) {
+                            utility = constructor.newInstance();
+                        } else {
+                            throw new IllegalArgumentException(
+                                                               "No valid constructor is found for " + utilityClass);
+                        }
+                    }
+                   
+                    // Cache the loaded utility
+                    addUtility(utility);
+                }
+            } catch (InvocationTargetException e) {
+                throw new IllegalArgumentException(e);
+            } catch (IOException e) {
+                throw new IllegalArgumentException(e);
+            } catch (ClassNotFoundException e) {
+                throw new IllegalArgumentException(e);
+            } catch (InstantiationException e) {
+                throw new IllegalArgumentException(e);
+            } catch (IllegalAccessException e) {
+                throw new IllegalArgumentException(e);
+            }
+        }
+        return utilityType.cast(utility);
+    }
+
+    /**
+     * Remove a utility based on the interface that it implements
+     *
+     * @param utility The utility to remove
+     *
+     * @throws IllegalArgumentException if utility is null
+     */
+    public void removeUtility(Object utility) {
+        if (utility == null) {
+            throw new IllegalArgumentException("Cannot remove null as a Service");
+        }
+
+        Set<Class<?>> interfaces = getAllInterfaces(utility.getClass());
+        for (Class<?> i : interfaces) {
+            utilities.remove(i);
+        }
+    }
+
+    /**
+     * Returns the set of interfaces implemented by the given class and its
+     * ancestors or a blank set if none
+     */
+    private static Set<Class<?>> getAllInterfaces(Class<?> clazz) {
+        Set<Class<?>> implemented = new HashSet<Class<?>>();
+        getAllInterfaces(clazz, implemented);
+        return implemented;
+    }
+
+    private static void getAllInterfaces(Class<?> clazz, Set<Class<?>> implemented) {
+        Class<?>[] interfaces = clazz.getInterfaces();
+        for (Class<?> interfaze : interfaces) {
+            if (Modifier.isPublic(interfaze.getModifiers())) {
+                implemented.add(interfaze);
+            }
+        }
+        Class<?> superClass = clazz.getSuperclass();
+        // Object has no superclass so check for null
+        if (superClass != null && !superClass.equals(Object.class)) {
+            getAllInterfaces(superClass, implemented);
+        }
+    }
+
+}