[SMX4-1475]add javax.ws.rs.client.FactoryFinder which can load ClientBuilder in OSGi container
git-svn-id: https://svn.apache.org/repos/asf/servicemix/smx4/specs/trunk@1504349 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/jsr339-api-2.0/src/main/java/javax/ws/rs/client/FactoryFinder.java b/jsr339-api-2.0/src/main/java/javax/ws/rs/client/FactoryFinder.java
new file mode 100644
index 0000000..400592b
--- /dev/null
+++ b/jsr339-api-2.0/src/main/java/javax/ws/rs/client/FactoryFinder.java
@@ -0,0 +1,219 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright (c) 2010-2013 Oracle and/or its affiliates. All rights reserved.
+ *
+ * The contents of this file are subject to the terms of either the GNU
+ * General Public License Version 2 only ("GPL") or the Common Development
+ * and Distribution License("CDDL") (collectively, the "License"). You
+ * may not use this file except in compliance with the License. You can
+ * obtain a copy of the License at
+ * http://glassfish.java.net/public/CDDL+GPL_1_1.html
+ * or packager/legal/LICENSE.txt. See the License for the specific
+ * language governing permissions and limitations under the License.
+ *
+ * When distributing the software, include this License Header Notice in each
+ * file and include the License file at packager/legal/LICENSE.txt.
+ *
+ * GPL Classpath Exception:
+ * Oracle designates this particular file as subject to the "Classpath"
+ * exception as provided by Oracle in the GPL Version 2 section of the License
+ * file that accompanied this code.
+ *
+ * Modifications:
+ * If applicable, add the following below the License Header, with the fields
+ * enclosed by brackets [] replaced by your own identifying information:
+ * "Portions Copyright [year] [name of copyright owner]"
+ *
+ * Contributor(s):
+ * If you wish your version of this file to be governed by only the CDDL or
+ * only the GPL Version 2, indicate your decision by adding "[Contributor]
+ * elects to include this software in this distribution under the [CDDL or GPL
+ * Version 2] license." If you don't indicate a single choice of license, a
+ * recipient has the option to distribute your version of this file under
+ * either the CDDL, the GPL Version 2 or to extend the choice of license to
+ * its licensees as provided above. However, if you add GPL Version 2 code
+ * and therefore, elected the GPL Version 2 license, then the option applies
+ * only if the new code is made subject to such option by the copyright
+ * holder.
+ */
+package javax.ws.rs.client;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.Properties;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * Factory finder utility class.
+ *
+ * @author Paul Sandoz
+ * @author Marc Hadley
+ * @since 1.0
+ */
+final class FactoryFinder {
+
+ private static final Logger LOGGER = Logger.getLogger(FactoryFinder.class.getName());
+
+ private FactoryFinder() {
+ // prevents instantiation
+ }
+
+ static ClassLoader getContextClassLoader() {
+ return AccessController.doPrivileged(
+ new PrivilegedAction<ClassLoader>() {
+
+ @Override
+ public ClassLoader run() {
+ ClassLoader cl = null;
+ try {
+ cl = Thread.currentThread().getContextClassLoader();
+ } catch (SecurityException ex) {
+ LOGGER.log(
+ Level.WARNING,
+ "Unable to get context classloader instance.",
+ ex);
+ }
+ return cl;
+ }
+ });
+ }
+
+ /**
+ * Creates an instance of the specified class using the specified
+ * <code>ClassLoader</code> object.
+ *
+ * @param className name of the class to be instantiated.
+ * @param classLoader class loader to be used.
+ * @return instance of the specified class.
+ * @throws ClassNotFoundException if the given class could not be found
+ * or could not be instantiated
+ */
+ private static Object newInstance(final String className, final ClassLoader classLoader) throws ClassNotFoundException {
+ try {
+ Class spiClass;
+ if (classLoader == null) {
+ spiClass = Class.forName(className);
+ } else {
+ try {
+ spiClass = Class.forName(className, false, classLoader);
+ } catch (ClassNotFoundException ex) {
+ LOGGER.log(
+ Level.FINE,
+ "Unable to load provider class " + className
+ + " using custom classloader " + classLoader.getClass().getName()
+ + " trying again with current classloader.",
+ ex);
+ spiClass = Class.forName(className);
+ }
+ }
+ return spiClass.newInstance();
+ } catch (ClassNotFoundException x) {
+ throw x;
+ } catch (Exception x) {
+ throw new ClassNotFoundException("Provider " + className + " could not be instantiated: " + x, x);
+ }
+ }
+
+ /**
+ * Finds the implementation <code>Class</code> object for the given
+ * factory name, or if that fails, finds the <code>Class</code> object
+ * for the given fallback class name. The arguments supplied MUST be
+ * used in order. If using the first argument is successful, the second
+ * one will not be used.
+ * <P>
+ * This method is package private so that this code can be shared.
+ *
+ * @param factoryId the name of the factory to find, which is
+ * a system property
+ * @param fallbackClassName the implementation class name, which is
+ * to be used only if nothing else
+ * is found; <code>null</code> to indicate that
+ * there is no fallback class name
+ * @return the <code>Class</code> object of the specified message factory;
+ * may not be <code>null</code>
+ * @throws ClassNotFoundException if the given class could not be found
+ * or could not be instantiated
+ */
+ static Object find(final String factoryId, final String fallbackClassName) throws ClassNotFoundException {
+
+ try {
+ // If we are deployed into an OSGi environment, leverage it
+ Class factoryClass = FactoryFinder.class.getClassLoader().loadClass(factoryId);
+ Class spiClass = org.apache.servicemix.specs.locator.OsgiLocator.locate(factoryClass, factoryId);
+ if (spiClass != null) {
+ return spiClass.newInstance();
+ }
+ } catch (Throwable e) {
+ }
+
+ ClassLoader classLoader = getContextClassLoader();
+
+ String serviceId = "META-INF/services/" + factoryId;
+ // try to find services in CLASSPATH
+ try {
+ InputStream is;
+ if (classLoader == null) {
+ is = ClassLoader.getSystemResourceAsStream(serviceId);
+ } else {
+ is = classLoader.getResourceAsStream(serviceId);
+ }
+
+ if (is != null) {
+ BufferedReader rd = new BufferedReader(new InputStreamReader(is, "UTF-8"));
+
+ String factoryClassName = rd.readLine();
+ rd.close();
+
+ if (factoryClassName != null && !"".equals(factoryClassName)) {
+ return newInstance(factoryClassName, classLoader);
+ }
+ }
+ } catch (Exception ex) {
+ LOGGER.log(Level.FINER, "Failed to load service " + factoryId + " from " + serviceId, ex);
+ }
+
+
+ // try to read from $java.home/lib/jaxrs.properties
+ try {
+ String javah = System.getProperty("java.home");
+ String configFile = javah + File.separator
+ + "lib" + File.separator + "jaxrs.properties";
+ File f = new File(configFile);
+ if (f.exists()) {
+ Properties props = new Properties();
+ props.load(new FileInputStream(f));
+ String factoryClassName = props.getProperty(factoryId);
+ return newInstance(factoryClassName, classLoader);
+ }
+ } catch (Exception ex) {
+ LOGGER.log(Level.FINER, "Failed to load service " + factoryId
+ + " from $java.home/lib/jaxrs.properties", ex);
+ }
+
+
+ // Use the system property
+ try {
+ String systemProp = System.getProperty(factoryId);
+ if (systemProp != null) {
+ return newInstance(systemProp, classLoader);
+ }
+ } catch (SecurityException se) {
+ LOGGER.log(Level.FINER, "Failed to load service " + factoryId
+ + " from a system property", se);
+ }
+
+ if (fallbackClassName == null) {
+ throw new ClassNotFoundException(
+ "Provider for " + factoryId + " cannot be found", null);
+ }
+
+ return newInstance(fallbackClassName, classLoader);
+ }
+}
