ModelsReader.java

/**
 * 
 */
package org.eclipse.papyrus.infra.core.resource;

import static org.eclipse.papyrus.infra.core.Activator.log;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.Platform;
import org.eclipse.papyrus.infra.core.Activator;
import org.eclipse.papyrus.infra.core.extension.ExtensionException;
import org.eclipse.papyrus.infra.core.extension.ExtensionUtils;

/**
 * A reader to read model from Eclipse extension and register them to the
 * specified ModelManager.
 * 
 * @author cedric dumoulin
 * 
 */
public class ModelsReader extends ExtensionUtils {

	/**
	 * Name of the extension (as declared in 'plugin.xml->extension
	 * point->xxx->ID')
	 */
	public static final String EXTENSION_POINT_NAME = "model";

	/** Name for the element "model" */
	public static final String MODEL_ELEMENT_NAME = "model";

	/** Name for the element "modelSnippet" */
	public static final String MODEL_SNIPPET_ELEMENT_NAME = "modelSnippet";

	/** Name for the element "modelSetSnippet" */
	public static final String MODEL_SET_SNIPPET_ELEMENT_NAME = "modelSetSnippet";

	/**
	 * Name of attribute used to set class name.
	 */
	private static final String CLASSNAME_ATTRIBUTE = "classname";

	/** Namespace where to look for the extension points. */
	protected String extensionPointNamespace;

	/**
	 * Create a ModelReader reading extension from the core namespace.
	 * 
	 * @param extensionPointNamespace
	 */
	public ModelsReader() {
		// Use this plugin namespace.
		this(Activator.PLUGIN_ID);
	}

	/**
	 * Create a ModelReader reading extension from the specified namespace. The
	 * namespace is usually the name of the plugin owning the {@link ModelSet}.
	 * 
	 * @param extensionPointNamespace
	 */
	public ModelsReader(String extensionPointNamespace) {
		super();
		this.extensionPointNamespace = extensionPointNamespace;
	}

	/**
	 * Populate the manager with models found in Eclipse extensions.
	 * 
	 * @param modelSet
	 */
	public void readModel(ModelSet modelSet) {

		// Actually, we register model manually.
		// TODO: read from Eclipse extension.
		// modelSet.registerModel( new SashModel() );
		// modelSet.registerModel( new NotationModel() );
		// // uml model
		// UmlModel umlModel = new ExtendedUmlModel();
		// umlModel.addModelSnippet(new UmlSnippet());
		// modelSet.registerModel(umlModel);
		// // global snippets
		// modelSet.addModelSetSnippet(new TypeCacheInitializer());

		// Reading data from plugins
		IConfigurationElement[] configElements = Platform.getExtensionRegistry().getConfigurationElementsFor(extensionPointNamespace, EXTENSION_POINT_NAME);
		addDeclaredModels(configElements, modelSet);
		addDeclaredModelSetSnippets(configElements, modelSet);
	}

	/**
	 * Read and instanciate declared models
	 * 
	 * @param modelSet
	 */
	private void addDeclaredModels(IConfigurationElement[] configElements, ModelSet modelSet) {

		for(IConfigurationElement ele : configElements) {

			// Check if it is a Model
			try {
				if(MODEL_ELEMENT_NAME.equals(ele.getName())) {
					IModel model = instanciateModel(ele);
					modelSet.registerModel(model);
					addDeclaredModelSnippet(ele, model);

					log.debug("model loaded: '" + model.getClass().getName() + "'");
				}
			} catch (ExtensionException e) {
				log.error("Problems occur while instanciating model", e);
			}
		}
	}

	/**
	 * Add ModelSet snippet
	 * 
	 * @param modelSet
	 */
	private void addDeclaredModelSetSnippets(IConfigurationElement[] configElements, ModelSet modelSet) {
		for(IConfigurationElement ele : configElements) {

			// Check if it is a Model
			try {
				if(MODEL_SET_SNIPPET_ELEMENT_NAME.equals(ele.getName())) {
					IModelSetSnippet snippet = instanciateModelSetSnippet(ele);
					modelSet.addModelSetSnippet(snippet);
					log.debug("modelSet snippet added: '" + modelSet.getClass().getName() + "().add(" + snippet.getClass().getName() + ")'");
				}
			} catch (ExtensionException e) {
				log.error("Problems occur while instanciating snippet", e);
			}
		}
	}

	/**
	 * Instanciate model declared in the configuration element.
	 * 
	 * @param ele
	 * @return
	 * @throws ExtensionException
	 */

	private IModel instanciateModel(IConfigurationElement ele) throws ExtensionException {

		@SuppressWarnings("unchecked")
		Class<IModel> modelInstance = (Class<IModel>)parseClass(ele, CLASSNAME_ATTRIBUTE, MODEL_ELEMENT_NAME);

		IModel model;
		try {
			model = modelInstance.newInstance();
		} catch (InstantiationException e) {
			throw new ExtensionException(e);
		} catch (IllegalAccessException e) {
			throw new ExtensionException(e);
		}

		return model;
	}

	/**
	 * Instanciate model snippet declared in the configuration element.
	 * 
	 * @param ele
	 * @return
	 * @throws ExtensionException
	 */
	private IModelSnippet instanciateModelSnippet(IConfigurationElement ele) throws ExtensionException {

		@SuppressWarnings("unchecked")
		Class<IModelSnippet> modelInstance = (Class<IModelSnippet>)parseClass(ele, CLASSNAME_ATTRIBUTE, MODEL_SNIPPET_ELEMENT_NAME);

		IModelSnippet snippet;
		try {
			snippet = modelInstance.newInstance();
		} catch (InstantiationException e) {
			throw new ExtensionException(e);
		} catch (IllegalAccessException e) {
			throw new ExtensionException(e);
		}

		return snippet;
	}

	/**
	 * Instanciate modelSet snippet declared in the configuration element.
	 * 
	 * @param ele
	 * @return
	 * @throws ExtensionException
	 */
	private IModelSetSnippet instanciateModelSetSnippet(IConfigurationElement ele) throws ExtensionException {

		@SuppressWarnings("unchecked")
		Class<IModelSetSnippet> modelInstance = (Class<IModelSetSnippet>)parseClass(ele, CLASSNAME_ATTRIBUTE, MODEL_SET_SNIPPET_ELEMENT_NAME);

		IModelSetSnippet snippet;
		try {
			snippet = modelInstance.newInstance();
		} catch (InstantiationException e) {
			throw new ExtensionException(e);
		} catch (IllegalAccessException e) {
			throw new ExtensionException(e);
		}

		return snippet;
	}

	/**
	 * Add associated snippets to the model.
	 * 
	 * @param parentElement
	 * @param model
	 */
	private void addDeclaredModelSnippet(IConfigurationElement parentElement, IModel model) {

		// Get children
		IConfigurationElement[] configElements = parentElement.getChildren(MODEL_SNIPPET_ELEMENT_NAME);

		for(IConfigurationElement ele : configElements) {
			try {
				IModelSnippet snippet = instanciateModelSnippet(ele);
				model.addModelSnippet(snippet);
				log.debug("model snippet added: '" + model.getClass().getName() + "().add(" + snippet.getClass().getName() + ")'");
			} catch (ExtensionException e) {
				log.error("Problems occur while instanciating model snippet", e);
			}
		}

	}

}