diff options
Diffstat (limited to 'sca-java-1.x/branches/sca-java-0.91/modules/extension-helper/src/main/java/org/apache/tuscany/sca/spi/impl/DiscoveryUtils.java')
-rw-r--r-- | sca-java-1.x/branches/sca-java-0.91/modules/extension-helper/src/main/java/org/apache/tuscany/sca/spi/impl/DiscoveryUtils.java | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/sca-java-1.x/branches/sca-java-0.91/modules/extension-helper/src/main/java/org/apache/tuscany/sca/spi/impl/DiscoveryUtils.java b/sca-java-1.x/branches/sca-java-0.91/modules/extension-helper/src/main/java/org/apache/tuscany/sca/spi/impl/DiscoveryUtils.java new file mode 100644 index 0000000000..adf69caf59 --- /dev/null +++ b/sca-java-1.x/branches/sca-java-0.91/modules/extension-helper/src/main/java/org/apache/tuscany/sca/spi/impl/DiscoveryUtils.java @@ -0,0 +1,134 @@ +/* + * 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.spi.impl; + +import java.io.BufferedReader; +import java.io.IOException; +import java.io.InputStream; +import java.io.InputStreamReader; +import java.lang.reflect.Constructor; +import java.net.URL; +import java.util.ArrayList; +import java.util.Enumeration; +import java.util.HashSet; +import java.util.List; +import java.util.Set; + +import org.apache.tuscany.sca.core.ExtensionPointRegistry; + +/** + * Discovers Activators in the classpath using the J2SE + * jar file extensions for Service Provider discovery + */ +public class DiscoveryUtils { + + public static <T> List<T> discoverActivators(Class<T> activatorClass, ClassLoader classLoader, ExtensionPointRegistry registry) { + Set<Class> activatorClasses = getServiceClasses(classLoader, activatorClass); + List<T> activators = new ArrayList<T>(); + for (Class<T> c : activatorClasses) { + try { + activators.add(c.cast(instantiateActivator(c, registry))); + } catch (Throwable e) { + e.printStackTrace(); // TODO: log + } + } + return activators; + } + + static Object instantiateActivator(Class activator, ExtensionPointRegistry registry) { + Constructor[] cs = activator.getConstructors(); + if (cs.length != 1) { + throw new RuntimeException("Activator must have only one constructors"); + } + + Class<?>[] paramTypes = cs[0].getParameterTypes(); + Object[] extensions = new Object[paramTypes.length]; + + for (int i=0; i< paramTypes.length; i++) { + extensions[i] = registry.getExtensionPoint(paramTypes[i]); + } + + try { + + return cs[0].newInstance(extensions); + + } catch (Exception e) { + throw new RuntimeException(e); + } + } + + static Set<Class> getServiceClasses(ClassLoader classLoader, Class name) { + try { + + Set<Class> set = new HashSet<Class>(); + Enumeration<URL> urls = classLoader.getResources("META-INF/services/" + name.getName()); + while (urls.hasMoreElements()) { + URL url = urls.nextElement(); + Set<String> services = getServiceClassNames(url); + if (services != null) { + for (String className : services) { + try { + set.add(Class.forName(className, true, classLoader)); + } catch (Throwable e) { + // TODO: log + } + } + } + } + return set; + + } catch (IOException e) { + throw new RuntimeException(e); + } + } + + static Set<String> getServiceClassNames(URL url) throws IOException { + Set<String> names = new HashSet<String>(); + InputStream is = url.openStream(); + 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(); + } + + if (is != null){ + try { + is.close(); + } catch( IOException ioe) { + //ignore + } + } + } + return names; + } + +} |