io.neba.core.resourcemodels.registration.ModelRegistrar.java Source code

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Here is the source code for io.neba.core.resourcemodels.registration.ModelRegistrar.java

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/*
  Copyright 2013 the original author or authors.
    
  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.
*/

package io.neba.core.resourcemodels.registration;

import io.neba.api.spi.ResourceModelFactory;
import io.neba.core.resourcemodels.adaptation.ResourceToModelAdapterUpdater;
import io.neba.core.resourcemodels.metadata.ResourceModelMetaDataRegistrar;
import io.neba.core.util.OsgiModelSource;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.osgi.service.component.annotations.Activate;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Deactivate;
import org.osgi.service.component.annotations.Reference;
import org.osgi.util.tracker.ServiceTracker;
import org.osgi.util.tracker.ServiceTrackerCustomizer;
import org.slf4j.Logger;

import java.util.Collection;

import static io.neba.core.util.BundleUtil.displayNameOf;
import static org.apache.commons.lang3.StringUtils.join;
import static org.slf4j.LoggerFactory.getLogger;

/**
 * Coordinates available models with NEBA's internal {@link ModelRegistry} and the {@link io.neba.core.resourcemodels.adaptation.ResourceToModelAdapter resource to model adapter factory}
 * provided by NEBA.
 * <p>
 * Specifically, this service tracks all {@link ResourceModelFactory resource model factory services} and {@link #registerModels(Bundle, ResourceModelFactory) registers}
 * or {@link #unregister(Bundle) unregisters} their models using the {@link ModelRegistry}. Subsequently, it
 * {@link ResourceToModelAdapterUpdater#refresh() refreshes} the resource to model adapter factory to reflect the changes.
 *</p>
 * @author Olaf Otto
 */
@Component(immediate = true)
public class ModelRegistrar {
    private final Logger logger = getLogger(getClass());

    @Reference
    private ModelRegistry registry;
    @Reference
    private ResourceToModelAdapterUpdater resourceToModelAdapterUpdater;
    @Reference
    private ResourceModelMetaDataRegistrar resourceModelMetaDataRegistrar;

    private ServiceTracker tracker;

    @Activate
    protected void activate(BundleContext context) {
        this.tracker = new ServiceTracker<>(context, ResourceModelFactory.class.getName(),
                new ServiceTrackerCustomizer<ResourceModelFactory, ResourceModelFactory>() {
                    @Override
                    public ResourceModelFactory addingService(ServiceReference<ResourceModelFactory> reference) {
                        final ResourceModelFactory factory = context.getService(reference);
                        registerModels(reference.getBundle(), factory);
                        return context.getService(reference);
                    }

                    @Override
                    public void modifiedService(ServiceReference<ResourceModelFactory> reference,
                            ResourceModelFactory service) {
                        final ResourceModelFactory factory = context.getService(reference);
                        unregister(reference.getBundle());
                        registerModels(reference.getBundle(), factory);
                    }

                    @Override
                    public void removedService(ServiceReference reference, ResourceModelFactory service) {
                        unregister(reference.getBundle());
                    }
                });
        this.tracker.open(true);
    }

    @Deactivate
    protected void deactivate() {
        this.tracker.close();
    }

    private void registerModels(Bundle bundle, ResourceModelFactory factory) {
        final Collection<ResourceModelFactory.ModelDefinition> modelDefinitions = factory.getModelDefinitions();

        logger.info("Registering {} resource models from bundle: " + displayNameOf(bundle) + " ...",
                modelDefinitions.size());
        modelDefinitions.forEach(d -> {
            final OsgiModelSource<Object> source = new OsgiModelSource<>(d, factory, bundle);
            this.resourceModelMetaDataRegistrar.register(source);
            this.registry.add(d.getResourceModel().types(), source);
            logger.debug("Registered model {} as a model for the resource types {}.", d.getName(),
                    join(d.getResourceModel().types(), ","));
        });

        this.resourceToModelAdapterUpdater.refresh();
    }

    private void unregister(Bundle bundle) {
        this.registry.removeResourceModels(bundle);
        this.resourceModelMetaDataRegistrar.removeMetadataForModelsIn(bundle);
        this.resourceToModelAdapterUpdater.refresh();
    }
}