org.eclipse.gmf.runtime.emf.ui/src/org/eclipse/gmf/runtime/emf/ui/services/modelingassistant/ModelingAssistantService.java

/******************************************************************************
 * Copyright (c) 2004, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    IBM Corporation - initial API and implementation 
 ****************************************************************************/

package org.eclipse.gmf.runtime.emf.ui.services.modelingassistant;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.gmf.runtime.common.core.service.ExecutionStrategy;
import org.eclipse.gmf.runtime.common.core.service.IOperation;
import org.eclipse.gmf.runtime.common.core.service.Service;
import org.eclipse.gmf.runtime.common.ui.services.util.ActivityFilterProviderDescriptor;
import org.eclipse.gmf.runtime.emf.type.core.IElementType;
import org.eclipse.gmf.runtime.emf.ui.internal.MslUIPlugin;

/**
 * This service is used to assist the user with modeling gestures.
 * 
 * @author cmahoney
 */
public class ModelingAssistantService
	extends Service
	implements IModelingAssistantProvider {

	/**
	 * A descriptor for <code>IModelingAssistantProvider</code> defined
	 * by a configuration element.
	 */
	protected static class ProviderDescriptor
		extends ActivityFilterProviderDescriptor {

		/** the provider configuration parsed from XML */
		private ModelingAssistantProviderConfiguration providerConfiguration;

		/**
		 * Constructs a <code>ISemanticProvider</code> descriptor for
		 * the specified configuration element.
		 * 
		 * @param element The configuration element describing the provider.
		 */
		public ProviderDescriptor(IConfigurationElement element) {
			super(element);

			this.providerConfiguration = ModelingAssistantProviderConfiguration
				.parse(element);
			assert providerConfiguration != null: "providerConfiguration is null"; //$NON-NLS-1$
		}

		public boolean provides(IOperation operation) {
			if (!super.provides(operation)) {
				return false;
			}
			if (!policyInitialized){
				policy = getPolicy();
				policyInitialized = true;
			}
			if (policy != null)
				return policy.provides(operation);

			return isSupportedInExtension(operation) ? getProvider().provides(
				operation) : false;
		}

		/**
		 * Checks if the operation is supported by the XML extension
		 * @param operation
		 * @return true if the operation is supported; false otherwise
		 */
		private boolean isSupportedInExtension(IOperation operation) {
			if (operation instanceof IModelingAssistantOperation) {
				String operationId = ((IModelingAssistantOperation) operation)
					.getId();
				IAdaptable context = ((IModelingAssistantOperation) operation)
					.getContext();

				return providerConfiguration.supports(operationId, context);
			}
			return false;
		}

	}

	/** The singleton instance of the modeling assistant service. */
	private final static ModelingAssistantService service = new ModelingAssistantService();

	static {
		service.configureProviders(MslUIPlugin.getPluginId(), "modelingAssistantProviders"); //$NON-NLS-1$
	}

	protected Service.ProviderDescriptor newProviderDescriptor(
		IConfigurationElement element) {
		return new ProviderDescriptor(element);
	}

	/**
	 * Retrieves the singleton instance of the modeling assistant service.
	 * 
	 * @return The modeling assistant service singleton.
	 */
	public static ModelingAssistantService getInstance() {
		return service;
	}

	/**
	 * Accepts a list that may contain other lists and returns a list
	 * containing all the objects.  Also removes duplicates.
	 * @param list
	 * @return the collapsed list
	 */
	private static List collapseList(List list) {
		List collapsedList = new ArrayList();

		for (Iterator iter = list.iterator(); iter.hasNext();) {
			Object object = iter.next();
			if (object instanceof List) {
				for (Iterator iterator = ((List) object).iterator(); iterator
					.hasNext();) {
					Object subObject = iterator.next();
					if (!collapsedList.contains(subObject)) {
						collapsedList.add(subObject);
					}
				}
			} else {
				collapsedList.add(object);
			}
		}
		return collapsedList;
	}

	/**
	 * Executes the <code>GetTypesOperation</code> using the 
	 * <code>FORWARD</code> execution strategy.
	 */
	public List getTypes(String hint, IAdaptable data) {
		List results = execute(ExecutionStrategy.FORWARD,
			new GetTypesOperation(hint, data));
		return collapseList(results);
	}

	/**
	 * Executes the <code>GetRelTypesOnSourceOperation</code> using the 
	 * <code>FORWARD</code> execution strategy.
	 */
	public List getRelTypesOnSource(IAdaptable source) {
		List results = execute(ExecutionStrategy.FORWARD,
			new GetRelTypesOnSourceOperation(source));
		return collapseList(results);
	}

	/**
	 * Executes the <code>GetRelTypesOnTargetOperation</code> using the 
	 * <code>FORWARD</code> execution strategy.
	 */
	public List getRelTypesOnTarget(IAdaptable target) {
		List results = execute(ExecutionStrategy.FORWARD,
			new GetRelTypesOnTargetOperation(target));
		return collapseList(results);
	}

	/**
	 * Executes the <code>GetRelTypesOnSourceAndTargetOperation</code> using the 
	 * <code>FORWARD</code> execution strategy.
	 */
	public List getRelTypesOnSourceAndTarget(IAdaptable source, IAdaptable target) {
		List results = execute(ExecutionStrategy.FORWARD,
			new GetRelTypesOnSourceAndTargetOperation(source, target));
		return collapseList(results);
	}

	/**
	 * Executes the <code>GetRelTypesForSREOnSourceOperation</code> using the 
	 * <code>FORWARD</code> execution strategy.
	 */
	public List getRelTypesForSREOnSource(IAdaptable source) {
		List results = execute(ExecutionStrategy.FORWARD,
			new GetRelTypesForSREOnSourceOperation(source));
		return collapseList(results);
	}

	/**
	 * Executes the <code>GetRelTypesForSREOnTargetOperation</code> using the 
	 * <code>FORWARD</code> execution strategy.
	 */
	public List getRelTypesForSREOnTarget(IAdaptable target) {
		List results = execute(ExecutionStrategy.FORWARD,
			new GetRelTypesForSREOnTargetOperation(target));
		return collapseList(results);
	}

	/**
	 * Executes the <code>GetTypesForSourceOperation</code> using the 
	 * <code>FORWARD</code> execution strategy.
	 */
	public List getTypesForSource(IAdaptable target,
		IElementType relationshipType) {
		List results = execute(ExecutionStrategy.FORWARD,
			new GetTypesForSourceOperation(target, relationshipType));
		return collapseList(results);
	}

	/**
	 * Executes the <code>GetTypesForTargetOperation</code> using the 
	 * <code>FORWARD</code> execution strategy.
	 */
	public List getTypesForTarget(IAdaptable source,
		IElementType relationshipType) {
		List results = execute(ExecutionStrategy.FORWARD,
			new GetTypesForTargetOperation(source, relationshipType));
		return collapseList(results);
	}

	/**
	 * Executes the <code>SelectExistingElementForSourceOperation</code> using the 
	 * <code>FIRST</code> execution strategy.
	 */
	public EObject selectExistingElementForSource(IAdaptable target,
		IElementType relationshipType) {
		List results = execute(ExecutionStrategy.FIRST,
			new SelectExistingElementForSourceOperation(target,
				relationshipType));
		return (EObject) results.get(0);
	}

	/**
	 * Executes the <code>SelectExistingElementForTargetOperation</code> using the 
	 * <code>FIRST</code> execution strategy.
	 */
	public EObject selectExistingElementForTarget(IAdaptable source,
		IElementType relationshipType) {
		List results = execute(ExecutionStrategy.FIRST,
			new SelectExistingElementForTargetOperation(source,
				relationshipType));
		return (EObject) results.get(0);
	}

	/**
	 * Executes the <code>GetTypesForPopupBarOperation</code> using the 
	 * <code>FORWARD</code> execution strategy.
	 */
	public List getTypesForPopupBar(IAdaptable host) {
		List results = execute(ExecutionStrategy.FORWARD,
			new GetTypesForPopupBarOperation(host));
		return collapseList(results);
	}

	/**
	 * Executes the <code>GetTypesForPopupBarOperation</code> using the 
	 * <code>FORWARD</code> execution strategy.
	 * 
	 * @see org.eclipse.gmf.runtime.emf.ui.services.modelingassistant.IModelingAssistantProvider#getTypesForActionBar(IAdaptable)
	 * @deprecated Renamed to {@link #getTypesForPopupBar(IAdaptable)}
	 */
	public List getTypesForActionBar(IAdaptable host) {
		List results = execute(ExecutionStrategy.FORWARD,
			new GetTypesForPopupBarOperation(host));
		return collapseList(results);
	}

}