1 files changed, 251 insertions, 0 deletions
diff --git a/tags/java/sca/2.0-M4-RC3/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ContextClassLoaderServiceDiscoverer.java b/tags/java/sca/2.0-M4-RC3/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ContextClassLoaderServiceDiscoverer.java
new file mode 100644
index 0000000000..08b2ac2c3f
--- /dev/null
+++ b/tags/java/sca/2.0-M4-RC3/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ContextClassLoaderServiceDiscoverer.java
@@ -0,0 +1,251 @@
+/*
+ * 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 static org.apache.tuscany.sca.extensibility.ServiceDeclarationParser.parseDeclaration;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.lang.ref.WeakReference;
+import java.net.URL;
+import java.net.URLConnection;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.security.PrivilegedActionException;
+import java.security.PrivilegedExceptionAction;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * A ServiceDiscoverer that find META-INF/services/... using the Context ClassLoader.
+ *
+ * @version $Rev$ $Date$
+ */
+public class ContextClassLoaderServiceDiscoverer implements ServiceDiscoverer {
+    private static final Logger logger = Logger.getLogger(ContextClassLoaderServiceDiscoverer.class.getName());
+
+    public class ServiceDeclarationImpl implements ServiceDeclaration {
+        private URL url;
+        private String className;
+        private Class<?> javaClass;
+        private Map<String, String> attributes;
+
+        public ServiceDeclarationImpl(URL url, String className, Map<String, String> attributes) {
+            super();
+            this.url = url;
+            this.className = className;
+            this.attributes = attributes;
+        }
+
+        public Map<String, String> getAttributes() {
+            return attributes;
+        }
+
+        public String getClassName() {
+            return className;
+        }
+
+        public URL getLocation() {
+            return url;
+        }
+
+        public Class<?> loadClass() throws ClassNotFoundException {
+            if (className == null) {
+                return null;
+            }
+            if (javaClass == null) {
+                javaClass = loadClass(className);
+            }
+            return javaClass;
+        }
+
+        public Class<?> loadClass(String className) throws ClassNotFoundException {
+            return Class.forName(className, false, classLoaderReference.get());
+        }
+
+        @Override
+        public String toString() {
+            StringBuffer sb = new StringBuffer();
+            sb.append("Location: ").append(url);
+            sb.append(" ClassLoader: ").append(classLoaderReference.get());
+            sb.append(" Attributes: ").append(attributes);
+            return sb.toString();
+        }
+
+        public URL getResource(final String name) {
+            return AccessController.doPrivileged(new PrivilegedAction<URL>() {
+                public URL run() {
+                    return classLoaderReference.get().getResource(name);
+                }
+            });
+        }
+
+        public boolean isAssignableTo(Class<?> serviceType) {
+            try {
+                loadClass();
+            } catch (ClassNotFoundException e) {
+                // Ignore 
+            }
+            return (javaClass != null && serviceType.isAssignableFrom(javaClass));
+        }
+    }
+
+    private WeakReference<ClassLoader> classLoaderReference;
+
+    public ContextClassLoaderServiceDiscoverer() {
+        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
+        this.classLoaderReference = new WeakReference<ClassLoader>(classLoader);
+    }
+    
+    public ClassLoader getContextClassLoader() {
+        return classLoaderReference.get();
+    }
+
+    private List<URL> getResources(final String name) throws IOException {
+        try {
+            return AccessController.doPrivileged(new PrivilegedExceptionAction<List<URL>>() {
+                public List<URL> run() throws IOException {
+                    List<URL> urls = Collections.list(classLoaderReference.get().getResources(name));
+                    return urls;
+                }
+            });
+        } catch (PrivilegedActionException e) {
+            throw (IOException)e.getException();
+        }
+    }
+
+    public ServiceDeclaration getServiceDeclaration(String name) throws IOException {
+        Collection<ServiceDeclaration> declarations = getServiceDeclarations(name);
+        if (declarations.isEmpty()) {
+            return null;
+        } else {
+            return declarations.iterator().next();
+        }
+    }
+
+    public Collection<ServiceDeclaration> getServiceDeclarations(String serviceName) {
+        Collection<ServiceDeclaration> descriptors = new HashSet<ServiceDeclaration>();
+
+        // http://java.sun.com/j2se/1.5.0/docs/api/javax/xml/xpath/XPathFactory.html
+        boolean isPropertyFile = "javax.xml.xpath.XPathFactory".equals(serviceName);
+        String name = "META-INF/services/" + serviceName;
+        boolean debug = logger.isLoggable(Level.FINE);
+        try {
+            for (final URL url : getResources(name)) {
+                if (debug) {
+                    logger.fine("Reading service provider file: " + url.toExternalForm());
+                }
+
+                // Allow privileged access to open URL stream. Add FilePermission to added to security
+                // policy file.
+                InputStream is;
+                try {
+                    is = AccessController.doPrivileged(new PrivilegedExceptionAction<InputStream>() {
+                        public InputStream run() throws IOException {
+                            URLConnection connection = url.openConnection();
+                            // TUSCANY-2539
+                            // Don't cache connections by default to stop Tuscany locking contribution jar files
+                            // done here as this is one of the first places we open a stream and the only way to
+                            // set the default is to set it on an instance of URLConnection
+                            connection.setDefaultUseCaches(false);
+                            connection.setUseCaches(false);
+                            return url.openStream();
+                        }
+                    });
+                } catch (PrivilegedActionException e) {
+                    throw (IOException)e.getException();
+                }
+                if (isPropertyFile) {
+                    // Load as a property file
+                    Properties props = new Properties();
+                    props.load(is);
+                    is.close();
+                    for (Map.Entry<Object, Object> e : props.entrySet()) {
+                        Map<String, String> attributes = new HashMap<String, String>();
+                        String key = (String)e.getKey();
+                        String value = (String)e.getValue();
+                        // Unfortunately, the xalan file only has the classname
+                        if (value == null || "".equals(value)) {
+                            value = key;
+                            key = "";
+                        }
+                        if (!"".equals(key)) {
+                            attributes.put(key, value);
+                            attributes.put("uri", key);
+                        }
+                        attributes.putAll(parseDeclaration(value));
+                        ServiceDeclarationImpl descriptor = new ServiceDeclarationImpl(url, value, attributes);
+                        descriptors.add(descriptor);
+                    }
+                    continue;
+                }
+                BufferedReader reader = null;
+                try {
+                    reader = new BufferedReader(new InputStreamReader(is));
+                    int count = 0;
+                    while (true) {
+                        String line = reader.readLine();
+                        if (line == null)
+                            break;
+                        line = line.trim();
+                        if (!line.startsWith("#") && !"".equals(line)) {
+                            String reg = line.trim();
+                            if (debug) {
+                                logger.fine("Registering service provider: " + reg);
+                            }
+
+                            Map<String, String> attributes = parseDeclaration(reg);
+                            String className = attributes.get("class");
+                            if (className == null) {
+                                // Add a unique class name to prevent equals() from returning true
+                                className = "_class_" + count;
+                                count++;
+                            }
+                            ServiceDeclarationImpl descriptor = new ServiceDeclarationImpl(url, className, attributes);
+                            descriptors.add(descriptor);
+                        }
+                    }
+                } finally {
+                    if (reader != null) {
+                        try {
+                            reader.close();
+                        } catch (IOException e) {
+                            // Ignore
+                        }
+                    }
+                }
+            }
+        } catch (IOException e) {
+            logger.log(Level.SEVERE, e.getMessage(), e);
+        }
+        return descriptors;
+
+    }
+
+}