Add a method to ServiceDiscovery to set context classloader for service providers in OSGi

git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@802470 13f79535-47bb-0310-9956-ffa450edef68

3 files changed, 131 insertions, 95 deletions

diff --git a/java/sca/modules/binding-ws-axis2/src/main/java/org/apache/tuscany/sca/binding/ws/axis2/Axis2ConfiguratorHelper.java b/java/sca/modules/binding-ws-axis2/src/main/java/org/apache/tuscany/sca/binding/ws/axis2/Axis2ConfiguratorHelper.java
index fcf8fa05d4..782cfd6066 100644
--- a/java/sca/modules/binding-ws-axis2/src/main/java/org/apache/tuscany/sca/binding/ws/axis2/Axis2ConfiguratorHelper.java
+++ b/java/sca/modules/binding-ws-axis2/src/main/java/org/apache/tuscany/sca/binding/ws/axis2/Axis2ConfiguratorHelper.java
@@ -19,17 +19,9 @@
 
 package org.apache.tuscany.sca.binding.ws.axis2;
 
-import java.io.IOException;
-import java.net.URL;
 import java.security.AccessController;
 import java.security.PrivilegedActionException;
 import java.security.PrivilegedExceptionAction;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Enumeration;
-import java.util.HashSet;
-import java.util.Set;
 
 import org.apache.axis2.AxisFault;
 import org.apache.axis2.context.ConfigurationContext;
@@ -43,66 +35,6 @@ import org.oasisopen.sca.ServiceRuntimeException;
 public class Axis2ConfiguratorHelper {
 
     /**
-     * This classloader is used in OSGi to work around XXXFactory.newInstance()
-     */
-    static class MultiParentClassLoader extends ClassLoader {
-        private final Collection<ClassLoader> classLoaders = new ArrayList<ClassLoader>();
-    
-        /**
-         * @param parent The parent classloaders
-         * @param loaders A list of classloaders to be used to load classes or resources
-         */
-        public MultiParentClassLoader(ClassLoader parent, ClassLoader[] loaders) {
-            super(parent);
-            if (loaders != null) {
-                for (ClassLoader cl : loaders) {
-                    if (cl != null && cl != parent && !classLoaders.contains(cl)) {
-                        this.classLoaders.add(cl);
-                    }
-                }
-            }
-        }
-    
-        @Override
-        protected Class<?> findClass(String className) throws ClassNotFoundException {
-            for (ClassLoader parent : classLoaders) {
-                try {
-                    return parent.loadClass(className);
-                } catch (ClassNotFoundException e) {
-                    continue;
-                }
-            }
-            throw new ClassNotFoundException(className);
-        }
-    
-        @Override
-        protected URL findResource(String resName) {
-            for (ClassLoader parent : classLoaders) {
-                URL url = parent.getResource(resName);
-                if (url != null) {
-                    return url;
-                }
-            }
-            return null;
-        }
-    
-        @Override
-        protected Enumeration<URL> findResources(String resName) throws IOException {
-            Set<URL> urlSet = new HashSet<URL>();
-            for (ClassLoader parent : classLoaders) {
-                Enumeration<URL> urls = parent.getResources(resName);
-                if (urls != null) {
-                    while (urls.hasMoreElements()) {
-                        urlSet.add(urls.nextElement());
-                    }
-                }
-            }
-            return Collections.enumeration(urlSet);
-        }
-    }
-
-    
-    /**
      * We cannot hold this method directly in the {@link TuscanyAxisConfigurator} class as the super class
      * uses the TCCL to load classes
      * 
@@ -124,20 +56,12 @@ public class Axis2ConfiguratorHelper {
                         // The axis2 class loader
                         ClassLoader cl1 = URLBasedAxisConfigurator.class.getClassLoader();
                         
-                        // The extensibility class loader that sees all 3rd party jars
-                        ClassLoader cl2 = ServiceDiscovery.getInstance().getContextClassLoader();
-                        ClassLoader tccl = Thread.currentThread().getContextClassLoader();
-                        ClassLoader newTccl = tccl;
-                        if (cl0 != tccl || cl1 != tccl || cl2 != tccl) {
-                            newTccl = new MultiParentClassLoader(null, new ClassLoader[] {cl0, cl1, cl2, tccl});
-                        }
-                        if (newTccl != null && newTccl != tccl) {
-                            Thread.currentThread().setContextClassLoader(newTccl);
-                        }
+                        ClassLoader tccl = ServiceDiscovery.getInstance().setContextClassLoader(cl0, cl1);
+                        
                         try {
                             return new TuscanyAxisConfigurator(isRampartRequired).getConfigurationContext();
                         } finally {
-                            if (newTccl != null && newTccl != tccl) {
+                            if (tccl != null) {
                                 Thread.currentThread().setContextClassLoader(tccl);
                             }
                         }
diff --git a/java/sca/modules/databinding-jaxb/src/main/java/org/apache/tuscany/sca/databinding/jaxb/JAXBContextCache.java b/java/sca/modules/databinding-jaxb/src/main/java/org/apache/tuscany/sca/databinding/jaxb/JAXBContextCache.java
index a8d99ad0dd..6b32f0844b 100644
--- a/java/sca/modules/databinding-jaxb/src/main/java/org/apache/tuscany/sca/databinding/jaxb/JAXBContextCache.java
+++ b/java/sca/modules/databinding-jaxb/src/main/java/org/apache/tuscany/sca/databinding/jaxb/JAXBContextCache.java
@@ -52,10 +52,10 @@ import javax.xml.bind.annotation.XmlRootElement;
 import javax.xml.bind.annotation.XmlSeeAlso;
 import javax.xml.bind.annotation.XmlTransient;
 import javax.xml.bind.annotation.XmlType;
+import javax.xml.datatype.DatatypeFactory;
 import javax.xml.transform.Source;
 
 import org.apache.tuscany.sca.databinding.util.LRUCache;
-import org.apache.tuscany.sca.extensibility.ServiceDeclaration;
 import org.apache.tuscany.sca.extensibility.ServiceDiscovery;
 
 /**
@@ -124,25 +124,15 @@ public class JAXBContextCache {
             return AccessController.doPrivileged(new PrivilegedExceptionAction<JAXBContext>() {
                 public JAXBContext run() throws JAXBException {
                     // Try to set up TCCL so that JAXBContext service discovery works in OSGi
-                    ClassLoader tccl = Thread.currentThread().getContextClassLoader();
-                    ClassLoader newTccl = tccl;
-                    try {
-                        ServiceDeclaration sd =
-                            ServiceDiscovery.getInstance().getServiceDeclaration(JAXBContext.class.getName());
-                        if (sd != null) {
-                            newTccl = sd.loadClass().getClassLoader();
-                        }
-                    } catch (Exception e) {
-                        // Ignore
-                    }
-                    if (newTccl != tccl) {
-                        Thread.currentThread().setContextClassLoader(newTccl);
-                    }
+                    ClassLoader tccl =
+                        ServiceDiscovery.getInstance().setContextClassLoader(JAXBContextCache.class.getClassLoader(),
+                                                                             JAXBContext.class.getName(),
+                                                                             DatatypeFactory.class.getName());
                     try {
                         JAXBContext context = JAXBContext.newInstance(classesToBeBound);
                         return context;
                     } finally {
-                        if (newTccl != tccl) {
+                        if (tccl != null) {
                             Thread.currentThread().setContextClassLoader(tccl);
                         }
                     }
diff --git a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ServiceDiscovery.java b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ServiceDiscovery.java
index 70274752e4..e92655146c 100644
--- a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ServiceDiscovery.java
+++ b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ServiceDiscovery.java
@@ -20,12 +20,16 @@
 package org.apache.tuscany.sca.extensibility;
 
 import java.io.IOException;
+import java.net.URL;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Comparator;
+import java.util.Enumeration;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Set;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -185,5 +189,123 @@ public final class ServiceDiscovery implements ServiceDiscoverer {
     public ClassLoader getContextClassLoader() {
         return discoverer.getContextClassLoader();
     }
+    
+    private static class ClassLoaderDelegate extends ClassLoader {
+        private final List<ClassLoader> classLoaders = new ArrayList<ClassLoader>();
+
+        /**
+         * @param parent The parent classloaders
+         * @param loaders A list of classloaders to be used to load classes or resources
+         */
+        public ClassLoaderDelegate(ClassLoader parent, Collection<ClassLoader> loaders) {
+            super(parent);
+            if (loaders != null) {
+                for (ClassLoader cl : loaders) {
+                    if (cl != null && cl != parent && !classLoaders.contains(cl)) {
+                        this.classLoaders.add(cl);
+                    }
+                }
+            }
+        }
+
+        @Override
+        protected Class<?> findClass(String className) throws ClassNotFoundException {
+            for (ClassLoader parent : classLoaders) {
+                try {
+                    return parent.loadClass(className);
+                } catch (ClassNotFoundException e) {
+                    continue;
+                }
+            }
+            throw new ClassNotFoundException(className);
+        }
+
+        @Override
+        protected URL findResource(String resName) {
+            for (ClassLoader parent : classLoaders) {
+                URL url = parent.getResource(resName);
+                if (url != null) {
+                    return url;
+                }
+            }
+            return null;
+        }
+
+        @Override
+        protected Enumeration<URL> findResources(String resName) throws IOException {
+            Set<URL> urlSet = new HashSet<URL>();
+            for (ClassLoader parent : classLoaders) {
+                Enumeration<URL> urls = parent.getResources(resName);
+                if (urls != null) {
+                    while (urls.hasMoreElements()) {
+                        urlSet.add(urls.nextElement());
+                    }
+                }
+            }
+            return Collections.enumeration(urlSet);
+        }
+    }
+
+    private ClassLoader getClassLoader(String serviceProvider) {
+        try {
+            ServiceDeclaration sd = getServiceDeclaration(serviceProvider);
+            if (sd != null) {
+                return sd.loadClass().getClassLoader();
+            }
+        } catch (Exception e) {
+            // Ignore
+        }
+        return null;
+    }
+    
+    /**
+     * Set the context classloader so that it can access the list of service providers
+     * @param parent The parent classloader
+     * @param serviceProviders A list of service provider names
+     * @return The old TCCL if a new one is set, otherwise null
+     */
+    public ClassLoader setContextClassLoader(ClassLoader parent, String... serviceProviders) {
+        List<ClassLoader> loaders = getClassLoaders(serviceProviders);
+        return setContextClassLoader(parent, loaders.toArray(new ClassLoader[loaders.size()]));
+    }
+
+    private List<ClassLoader> getClassLoaders(String... serviceProviders) {
+        List<ClassLoader> loaders = new ArrayList<ClassLoader>();
+        for (String sp : serviceProviders) {
+            ClassLoader loader = getClassLoader(sp);
+            if (loader != null) {
+                if (!loaders.contains(loader)) {
+                    loaders.add(loader);
+                }
+            }
+        }
+        return loaders;
+    }
+
+    public ClassLoader setContextClassLoader(ClassLoader parent, ClassLoader... delegates) {
+        ClassLoader tccl = Thread.currentThread().getContextClassLoader();
+        List<ClassLoader> loaders = new ArrayList<ClassLoader>();
+        for (ClassLoader loader : delegates) {
+            if (loader != null && loader != tccl && loader != parent) {
+                if (!loaders.contains(loader)) {
+                    loaders.add(loader);
+                }
+            }
+        }
+        if (!loaders.isEmpty()) {
+            ClassLoader cl = getContextClassLoader();
+            if (cl != parent) {
+                loaders.add(cl);
+            }
+            if (tccl != parent) {
+                loaders.add(tccl);
+            }
+            ClassLoader newTccl = new ClassLoaderDelegate(parent, loaders);
+            Thread.currentThread().setContextClassLoader(newTccl);
+            return tccl;
+        } else {
+            return null;
+        }
+    }
 
 }