Is PluginVisitorRegistry not a better name than PluginVisitors? The convention to append "s" after another class name has many meanings, like providing static util methods. I think calling it a ..Registry is clearer.
Sent from my iPhone > On 2014/05/26, at 12:59, [email protected] wrote: > > Author: mattsicker > Date: Mon May 26 03:59:52 2014 > New Revision: 1597509 > > URL: http://svn.apache.org/r1597509 > Log: > Add PluginVisitors registry class. > > - Registers the PluginAttribute visitor by default. > - Will be adding other visitor implementations over time. > > Added: > > logging/log4j/log4j2/trunk/log4j-core/src/main/java/org/apache/logging/log4j/core/config/plugins/visitors/PluginVisitors.java > (with props) > > Added: > logging/log4j/log4j2/trunk/log4j-core/src/main/java/org/apache/logging/log4j/core/config/plugins/visitors/PluginVisitors.java > URL: > http://svn.apache.org/viewvc/logging/log4j/log4j2/trunk/log4j-core/src/main/java/org/apache/logging/log4j/core/config/plugins/visitors/PluginVisitors.java?rev=1597509&view=auto > ============================================================================== > --- > logging/log4j/log4j2/trunk/log4j-core/src/main/java/org/apache/logging/log4j/core/config/plugins/visitors/PluginVisitors.java > (added) > +++ > logging/log4j/log4j2/trunk/log4j-core/src/main/java/org/apache/logging/log4j/core/config/plugins/visitors/PluginVisitors.java > Mon May 26 03:59:52 2014 > @@ -0,0 +1,81 @@ > +/* > + * 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.logging.log4j.core.config.plugins.visitors; > + > +import java.lang.annotation.Annotation; > +import java.util.Map; > +import java.util.concurrent.ConcurrentHashMap; > + > +import org.apache.logging.log4j.Logger; > +import org.apache.logging.log4j.core.config.plugins.PluginAttribute; > +import org.apache.logging.log4j.status.StatusLogger; > + > +/** > + * Registry for associating Plugin annotations with PluginVisitor > implementations. > + */ > +public final class PluginVisitors { > + > + private static final Logger LOGGER = StatusLogger.getLogger(); > + > + // map of annotation classes to their corresponding PluginVisitor classes > + // generics are fun! > + private static final Map<Class<? extends Annotation>, Class<? extends > PluginVisitor<? extends Annotation>>> REGISTRY; > + > + static { > + // register the default PluginVisitor classes > + REGISTRY = new ConcurrentHashMap<Class<? extends Annotation>, > Class<? extends PluginVisitor<? extends Annotation>>>(); > + registerVisitor(PluginAttribute.class, PluginAttributeVisitor.class); > + } > + > + private PluginVisitors() { > + } > + > + /** > + * Registers a PluginVisitor class associated to a specific annotation. > + * > + * @param annotation the Plugin annotation to associate with. > + * @param helper the PluginVisitor class to use for the annotation. > + * @param <A> the Plugin annotation type. > + */ > + public static <A extends Annotation> void registerVisitor(final Class<A> > annotation, > + final Class<? > extends PluginVisitor<A>> helper) { > + REGISTRY.put(annotation, helper); > + } > + > + /** > + * Creates a PluginVisitor instance for the given annotation class. This > instance must be further populated with > + * data to be useful. Such data is passed through both the setters and > the visit method. > + * > + * @param annotation the Plugin annotation class to find a PluginVisitor > for. > + * @param <A> the Plugin annotation type. > + * @return a PluginVisitor instance if one could be created, or {@code > null} otherwise. > + */ > + @SuppressWarnings("unchecked") // we're keeping track of types, thanks > + public static <A extends Annotation> PluginVisitor<A> findVisitor(final > Class<A> annotation) { > + try { > + final Class<PluginVisitor<A>> clazz = (Class<PluginVisitor<A>>) > REGISTRY.get(annotation); > + if (clazz == null) { > + return null; > + } > + return clazz.newInstance(); > + } catch (final Exception e) { > + LOGGER.debug("No PluginVisitor found for annotation: {}.", > annotation); > + return null; > + } > + } > +} > > Propchange: > logging/log4j/log4j2/trunk/log4j-core/src/main/java/org/apache/logging/log4j/core/config/plugins/visitors/PluginVisitors.java > ------------------------------------------------------------------------------ > svn:eol-style = native > > --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
