Cache the class objects for the dynamically loaded providers to avoid…

… repeated (and expensive) class.forName calls

rt/frontend/jaxrs/src/main/java/org/apache/cxf/jaxrs/provider/ProviderFactory.java

@@ -93,12 +93,75 @@ public abstract class ProviderFactory {
  private static final String BUS_PROVIDERS_ALL = "org.apache.cxf.jaxrs.bus.providers";
  private static final String PROVIDER_CACHE_ALLOWED = "org.apache.cxf.jaxrs.provider.cache.allowed";
  private static final String PROVIDER_CACHE_CHECK_ALL = "org.apache.cxf.jaxrs.provider.cache.checkAllCandidates";
-
+
+
+ static class LazyProviderClass {
+ // class to Lazily call the ClassLoaderUtil.loadClass, but do it once
+ // and cache the result. Then use the class to create instances as needed.
+ // This avoids calling loadClass every time a factory is initialized as
+ // calling loadClass is super expensive, particularly if the class
+ // cannot be found and particularly in osgi where the search is very complex.
+ // This would record that the class is not found and prevent future
+ // searches.
+ final String className;
+ volatile boolean initialized;
+ Class<?> cls;
+
+ LazyProviderClass(String cn) {
+ className = cn;
+ }
+
+ synchronized void loadClass() {
+ if (!initialized) {
+ try {
+ cls = ClassLoaderUtils.loadClass(className, ProviderFactory.class);
+ } catch (final Throwable ex) {
+ LOG.fine(className + " not available, skipping");
+ }
+ initialized = true;
+ }
+ }
+
+ public Object tryCreateInstance(Bus bus) {
+ if (!initialized) {
+ loadClass();
+ }
+ if (cls != null) {
+ try {
+ for (Constructor<?> c : cls.getConstructors()) {
+ if (c.getParameterTypes().length == 1 && c.getParameterTypes()[0] == Bus.class) {
+ return c.newInstance(bus);
+ }
+ }
+ return cls.newInstance();
+ } catch (Throwable ex) {
+ String message = "Problem with creating the provider " + className;
+ if (ex.getMessage() != null) {
+ message += ": " + ex.getMessage();
+ } else {
+ message += ", exception class : " + ex.getClass().getName();
+ }
+ LOG.fine(message);
+ }
+ }
+ return null;
+ }
+ };
+
+ private static final LazyProviderClass DATA_SOURCE_PROVIDER_CLASS = 
+ new LazyProviderClass("org.apache.cxf.jaxrs.provider.DataSourceProvider");
+ private static final LazyProviderClass JAXB_PROVIDER_CLASS = 
+ new LazyProviderClass(JAXB_PROVIDER_NAME);
+ private static final LazyProviderClass JAXB_ELEMENT_PROVIDER_CLASS = 
+ new LazyProviderClass("org.apache.cxf.jaxrs.provider.JAXBElementTypedProvider");
+ private static final LazyProviderClass MULTIPART_PROVIDER_CLASS = 
+ new LazyProviderClass("org.apache.cxf.jaxrs.provider.MultipartProvider");
+
  protected Map<NameKey, ProviderInfo<ReaderInterceptor>> readerInterceptors =
  new NameKeyMap<>(true);
  protected Map<NameKey, ProviderInfo<WriterInterceptor>> writerInterceptors =
  new NameKeyMap<>(true);
-
+ 
  private List<ProviderInfo<MessageBodyReader<?>>> messageReaders =
  new ArrayList<>();
  private List<ProviderInfo<MessageBodyWriter<?>>> messageWriters =
@@ -120,6 +183,7 @@ public abstract class ProviderFactory {
  private Comparator<?> providerComparator;
 
  private ProviderCache providerCache;
+
 
  protected ProviderFactory(Bus bus) {
  this.bus = bus;
@@ -144,28 +208,17 @@ protected static void initFactory(ProviderFactory factory) {
  false,
  new BinaryDataProvider<Object>(),
  new SourceProvider<Object>(),
- tryCreateInstance("org.apache.cxf.jaxrs.provider.DataSourceProvider"),
+ DATA_SOURCE_PROVIDER_CLASS.tryCreateInstance(factory.getBus()),
  new FormEncodingProvider<Object>(),
  new StringTextProvider(),
  new PrimitiveTextProvider<Object>(),
- tryCreateInstance(JAXB_PROVIDER_NAME),
- tryCreateInstance("org.apache.cxf.jaxrs.provider.JAXBElementTypedProvider"),
- tryCreateInstance("org.apache.cxf.jaxrs.provider.MultipartProvider"));
+ JAXB_PROVIDER_CLASS.tryCreateInstance(factory.getBus()),
+ JAXB_ELEMENT_PROVIDER_CLASS.tryCreateInstance(factory.getBus()),
+ MULTIPART_PROVIDER_CLASS.tryCreateInstance(factory.getBus()));
  Object prop = factory.getBus().getProperty("skip.default.json.provider.registration");
  if (!PropertyUtils.isTrue(prop)) {
  factory.setProviders(false, false, createProvider(JSON_PROVIDER_NAME, factory.getBus()));
  }
-
- }
-
- protected static Object tryCreateInstance(final String className) {
- try {
- final Class<?> cls = ClassLoaderUtils.loadClass(className, ProviderFactory.class);
- return cls.getConstructor().newInstance();
- } catch (final Throwable ex) {
- LOG.fine(className + " not available, skipping");
- }
- return null;
  }
 
  protected static Object createProvider(String className, Bus bus) {