IncQueryBaseFactory.java

/*******************************************************************************
 * Copyright (c) 2010-2012, Istvan Rath and Daniel Varro
 * 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:
 *   Tamas Szabo, Gabor Bergmann - initial API and implementation
 *******************************************************************************/

package org.eclipse.incquery.runtime.base.api;

import java.util.Set;

import org.apache.log4j.Logger;
import org.eclipse.emf.common.notify.Notifier;
import org.eclipse.emf.ecore.EReference;
import org.eclipse.incquery.runtime.base.core.NavigationHelperImpl;
import org.eclipse.incquery.runtime.base.core.TransitiveClosureHelperImpl;
import org.eclipse.incquery.runtime.base.exception.IncQueryBaseException;

/**
 * Factory class for the utils in the library: - NavigationHelper (automatic and manual) - TransitiveClosureUtil
 * 
 * @author Tamas Szabo
 * 
 */
public class IncQueryBaseFactory {

    private static IncQueryBaseFactory instance;

    /**
     * Get the singleton instance of IncQueryBaseFactory.
     * 
     * @return the singleton instance
     */
    public synchronized static IncQueryBaseFactory getInstance() {
        if (instance == null) {
            instance = new IncQueryBaseFactory();
        }

        return instance;
    }

    protected IncQueryBaseFactory() {
        super();
    }

    /**
     * The method creates a {@link NavigationHelper} index for the given EMF model root.
     * <p>
     * A NavigationHelper in wildcard mode will process and index all EStructuralFeatures, EClasses and EDatatypes. If
     * wildcard mode is off, the client will have to manually register the interesting aspects of the model.
     * 
     * @see NavigationHelper
     * 
     * @param emfRoot
     *            the root of the EMF tree to be indexed. Recommended: Resource or ResourceSet. Can be null - you can
     *            add a root later using {@link NavigationHelper#addRoot(Notifier)}
     * @param wildcardMode
     *            true if all aspects of the EMF model should be indexed automatically, false if manual registration of
     *            interesting aspects is desirable
     * @param logger
     *            the log output where errors will be logged if encountered during the operation of the
     *            NavigationHelper; if null, the default logger for {@link NavigationHelper} is used.
     * @return the NavigationHelper instance
     * @throws IncQueryBaseException
     */
    public NavigationHelper createNavigationHelper(Notifier emfRoot, boolean wildcardMode, Logger logger)
            throws IncQueryBaseException {
        if (logger == null)
            logger = Logger.getLogger(NavigationHelper.class);
        return new NavigationHelperImpl(emfRoot, wildcardMode, logger);
    }

    /**
     * The method creates a TransitiveClosureHelper instance for the given EMF model root.
     * 
     * <p>
     * One must specify the set of EReferences that will be considered as edged. The set can contain multiple elements;
     * this way one can query forward and backward reachability information along heterogenous paths.
     * 
     * @param emfRoot
     *            the root of the EMF tree to be processed. Recommended: Resource or ResourceSet.
     * @param referencesToObserve
     *            the set of references to observe
     * @return the TransitiveClosureHelper instance
     * @throws IncQueryBaseException
     */
    public TransitiveClosureHelper createTransitiveClosureHelper(Notifier emfRoot, Set<EReference> referencesToObserve)
            throws IncQueryBaseException {
        return new TransitiveClosureHelperImpl(emfRoot, referencesToObserve);
    }

}