/*
 * 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 org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.core.config.plugins.PluginVisitorStrategy;
import org.apache.logging.log4j.status.StatusLogger;

Utility class to locate an appropriate PluginVisitor implementation for an annotation. /**
 * Utility class to locate an appropriate {@link PluginVisitor} implementation for an annotation.
 */
public final class PluginVisitors {

    private static final Logger LOGGER = StatusLogger.getLogger();

    private PluginVisitors() {
    }

    
Creates a PluginVisitor instance for the given annotation class using metadata provided by the annotation's PluginVisitorStrategy annotation. This instance must be further populated with data to be useful. Such data is passed through both the setters and the visit method. 
Params:
annotation – the Plugin annotation class to find a PluginVisitor for.
Returns:
a PluginVisitor instance if one could be created, or null otherwise./**
     * Creates a PluginVisitor instance for the given annotation class using metadata provided by the annotation's
     * {@link PluginVisitorStrategy} annotation. 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.
     * @return a PluginVisitor instance if one could be created, or {@code null} otherwise.
     */
    public static PluginVisitor<? extends Annotation> findVisitor(final Class<? extends Annotation> annotation) {
        final PluginVisitorStrategy strategy = annotation.getAnnotation(PluginVisitorStrategy.class);
        if (strategy == null) {
            return null;
        }
        try {
            return strategy.value().newInstance();
        } catch (final Exception e) {
            LOGGER.error("Error loading PluginVisitor [{}] for annotation [{}].", strategy.value(), annotation, e);
            return null;
        }
    }
}