io.wcm.config.core.impl.ApplicationImplementationPicker.java Source code

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Here is the source code for io.wcm.config.core.impl.ApplicationImplementationPicker.java

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/*
 * #%L
 * wcm.io
 * %%
 * Copyright (C) 2014 wcm.io
 * %%
 * Licensed 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.
 * #L%
 */
package io.wcm.config.core.impl;

import io.wcm.config.core.management.Application;
import io.wcm.config.core.management.ApplicationFinder;

import org.apache.commons.lang3.StringUtils;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Property;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.Service;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.models.spi.ImplementationPicker;
import org.osgi.framework.Constants;

/**
 * Sling Models {@link ImplementationPicker} implementation that checks if an application is associated
 * with the given adaptable, and then chooses the implementation that is annotated for this application.
 * <p>
 * If no application is associated with the adaptable, or no implementation for the detected application exists, the
 * first implementation without @Application annotation is used.
 * </p>
 */
@Component(immediate = true)
@Service(ImplementationPicker.class)
@Property(name = Constants.SERVICE_RANKING, intValue = 1000)
public class ApplicationImplementationPicker implements ImplementationPicker {

    @Reference
    private ApplicationFinder applicationFinder;

    @Override
    public Class<?> pick(Class<?> adapterType, Class<?>[] implementationsTypes, Object adaptable) {
        Class<?> classMatchingApplication = pickMatchingApplication(implementationsTypes, adaptable);
        if (classMatchingApplication != null) {
            return classMatchingApplication;
        }
        return pickFirstWithoutApplication(implementationsTypes);
    }

    private Class<?> pickMatchingApplication(Class<?>[] implementationsTypes, Object adaptable) {
        String applicationId = getApplicationId(adaptable);
        if (applicationId != null) {
            for (Class<?> clazz : implementationsTypes) {
                io.wcm.config.spi.annotations.Application applicationAnnotation = clazz
                        .getAnnotation(io.wcm.config.spi.annotations.Application.class);
                if (applicationAnnotation != null
                        && StringUtils.equals(applicationId, applicationAnnotation.value())) {
                    return clazz;
                }
            }
        }
        return null;
    }

    private String getApplicationId(Object adaptable) {
        Resource resource = AdaptableUtil.getResource(adaptable);
        if (resource != null) {
            Application application = applicationFinder.find(resource);
            if (application != null) {
                return application.getApplicationId();
            }
        }
        return null;
    }

    private Class<?> pickFirstWithoutApplication(Class<?>[] implementationsTypes) {
        for (Class<?> clazz : implementationsTypes) {
            if (!clazz.isAnnotationPresent(io.wcm.config.spi.annotations.Application.class)) {
                return clazz;
            }
        }
        return null;
    }

}