Address @XmlSeeAlso limitation. Provide the ability to inject the JAXB types

[controller.git] / opendaylight / northbound / commons / src / main / java / org / opendaylight / controller / northbound / commons / NorthboundApplication.java

diff --git a/opendaylight/northbound/commons/src/main/java/org/opendaylight/controller/northbound/commons/NorthboundApplication.java b/opendaylight/northbound/commons/src/main/java/org/opendaylight/controller/northbound/commons/NorthboundApplication.java
new file mode 100644 (file)
index 0000000..1d3919f
--- /dev/null
+++ b/opendaylight/northbound/commons/src/main/java/org/opendaylight/controller/northbound/commons/NorthboundApplication.java
@@ -0,0 +1,148 @@
+/**
+ * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+
+package org.opendaylight.controller.northbound.commons;
+
+import java.util.Dictionary;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import javax.ws.rs.core.Application;
+import javax.ws.rs.ext.ContextResolver;
+import javax.xml.bind.JAXBContext;
+import javax.xml.bind.JAXBException;
+import javax.xml.bind.annotation.XmlRootElement;
+
+import org.codehaus.jackson.jaxrs.JacksonJaxbJsonProvider;
+import org.opendaylight.controller.northbound.bundlescanner.IBundleScanService;
+import org.osgi.framework.Bundle;
+import org.osgi.framework.BundleContext;
+import org.osgi.framework.BundleReference;
+import org.osgi.framework.FrameworkUtil;
+import org.osgi.framework.ServiceException;
+import org.osgi.framework.ServiceReference;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Instance of javax.ws.rs.core.Application used to return the classes
+ * that will be instantiated for JAXRS processing. This hooks onto the
+ * bundle scanner service to provide JAXB classes to JAX-RS for prorcessing.
+ */
+@SuppressWarnings("unchecked")
+public class NorthboundApplication extends Application {
+    public static final String JAXRS_RESOURCES_MANIFEST_NAME = "Jaxrs-Resources";
+    private static final Logger LOGGER = LoggerFactory.getLogger(NorthboundApplication.class);
+
+    ////////////////////////////////////////////////////////////////
+    //  Application overrides
+    ////////////////////////////////////////////////////////////////
+
+    @Override
+    public Set<Object> getSingletons() {
+        Set<Object> singletons = new HashSet<Object>();
+        singletons.add(new ContextResolver<JAXBContext>() {
+            @Override
+            public JAXBContext getContext(Class<?> type) {
+                return newJAXBContext();
+            }
+
+        } );
+        singletons.add(new JacksonJaxbJsonProvider());
+        return singletons;
+    }
+
+    @Override
+    public Set<Class<?>> getClasses() {
+        Set<Class<?>> result = new HashSet<Class<?>>();
+        result.addAll(findJAXRSResourceClasses());
+        return result;
+    }
+
+    private BundleContext getBundleContext() {
+        ClassLoader tlcl = Thread.currentThread().getContextClassLoader();
+        Bundle bundle = null;
+
+        if (tlcl instanceof BundleReference) {
+            bundle = ((BundleReference) tlcl).getBundle();
+        } else {
+            LOGGER.warn("Unable to determine the bundle context based on " +
+                        "thread context classloader.");
+            bundle = FrameworkUtil.getBundle(this.getClass());
+        }
+        return (bundle == null ? null : bundle.getBundleContext());
+    }
+
+    private static final IBundleScanService lookupBundleScanner(BundleContext ctx) {
+        ServiceReference svcRef = ctx.getServiceReference(IBundleScanService.class);
+        if (svcRef == null) {
+            throw new ServiceException("Unable to lookup IBundleScanService");
+        }
+        return IBundleScanService.class.cast(ctx.getService(svcRef));
+    }
+
+    private final JAXBContext newJAXBContext() {
+        BundleContext ctx = getBundleContext();
+        IBundleScanService svc = lookupBundleScanner(ctx);
+        try {
+            List<Class<?>> cls = svc.getAnnotatedClasses(ctx,
+                    new String[] { XmlRootElement.class.getPackage().getName() },
+                    true);
+            return JAXBContext.newInstance(cls.toArray(new Class[cls.size()]));
+        } catch (JAXBException je) {
+            LOGGER.error("Error creating JAXBContext", je);
+            return null;
+        }
+    }
+
+    private final Set<Class<?>> findJAXRSResourceClasses() {
+        BundleContext ctx = getBundleContext();
+        String bundleName = ctx.getBundle().getSymbolicName();
+        Set<Class<?>> result = new HashSet<Class<?>>();
+        ServiceException recordException = null;
+        try {
+            IBundleScanService svc = lookupBundleScanner(ctx);
+            result.addAll(svc.getAnnotatedClasses(ctx,
+                    new String[] { javax.ws.rs.Path.class.getName() }, false));
+        } catch (ServiceException se) {
+            recordException = se;
+            LOGGER.debug("Error finding JAXRS resource annotated classes in " +
+                    "bundle: {} error: {}.", bundleName, se.getMessage());
+            // the bundle scan service cannot be lookedup. Lets attempt to
+            // lookup the resources from the bundle manifest header
+            Dictionary<String,String> headers = ctx.getBundle().getHeaders();
+            String header = headers.get(JAXRS_RESOURCES_MANIFEST_NAME);
+            if (header != null) {
+                for (String s : header.split(",")) {
+                    s = s.trim();
+                    if (s.length() > 0) {
+                        try {
+                            result.add(ctx.getBundle().loadClass(s));
+                        } catch (ClassNotFoundException cnfe) {
+                            LOGGER.error("Cannot load class: {} in bundle: {} " +
+                                    "defined as MANIFEST JAX-RS resource", s, bundleName, cnfe);
+                        }
+                    }
+                }
+            }
+
+        }
+
+        if (result.size() == 0) {
+            if (recordException != null) {
+                throw recordException;
+            } else {
+                throw new ServiceException("No resource classes found in bundle:" +
+                        ctx.getBundle().getSymbolicName());
+            }
+        }
+        return result;
+    }
+
+}