// $Id: ExtensionMechanismsHelper.java,v 1.29 2004/08/20 23:54:17 d00mst Exp $
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package org.argouml.model.uml.foundation.extensionmechanisms;

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

import org.argouml.kernel.Project;
import org.argouml.kernel.ProjectManager;
import org.argouml.model.ModelFacade;
import org.argouml.model.uml.foundation.core.CoreHelper;
import org.argouml.model.uml.modelmanagement.ModelManagementHelper;

import ru.novosoft.uml.foundation.core.MModelElement;
import ru.novosoft.uml.foundation.core.MNamespace;
import ru.novosoft.uml.foundation.extension_mechanisms.MStereotype;
import ru.novosoft.uml.model_management.MModel;

/**
 * Helper class for UML Foundation::ExtensionMechanisms Package.
 *
 * Current implementation is a placeholder.
 *
 * @since ARGO0.11.2
 * @author Thierry Lach
 * @stereotype singleton
 */
public class ExtensionMechanismsHelper {

    /** Don't allow instantiation.
     */
    private ExtensionMechanismsHelper() {
    }

    /** Singleton instance.
     */
    private static ExtensionMechanismsHelper singleton =
	new ExtensionMechanismsHelper();


    /**
     * Singleton instance access method.
     *
     * @return the singleton
     */
    public static ExtensionMechanismsHelper getHelper() {
        return singleton;
    }

    /**
     * Returns all stereotypes in a namespace, but not those in a subnamespace.
     *
     * @param ns is the namespace.
     * @return a Collection with the stereotypes.
     */
    public Collection getStereotypes(MNamespace ns) {
        List l = new ArrayList();
        if (ns == null) return l;
    	Iterator it = ns.getOwnedElements().iterator();
    	while (it.hasNext()) {
	    Object o = it.next();
	    if (o instanceof MStereotype) {
		l.add(o);
	    }
    	}
    	return l;
    }

    /**
     * Returns all stereotypes in some model.
     *
     * TODO: This method can never be called, and you would probably not want
     * to since it does exactly the same thing as the method above (which is
     * the one you will call if you try).
     *
     * @param ns is the model.
     * @return Collection The stereotypes found. An empty arraylist is returned
     * if nothing is found.
     */
    public Collection getStereotypes(MModel ns) {
        List l = new ArrayList();
        if (ns == null) return l;
        Iterator it = ns.getOwnedElements().iterator();
        while (it.hasNext()) {
            Object o = it.next();
            if (o instanceof MStereotype) {
                l.add(o);
            }
        }
        return l;
    }

    /**
     * Finds a stereotype in some namespace, but not in its subnamespaces.
     * Returns null if no such stereotype is found.
     *
     * TODO: What if stereo.getName() or stereo.getBaseClass() is null?
     * Then you know immediately that none will be found, but is that the
     * correct answer?
     *
     * @return the stereotype found or null.
     * @param ns is the namespace.
     * @param stereo is the stereotype.
     */
    public MStereotype getStereotype(MNamespace ns, MStereotype stereo) {
    	String name = stereo.getName();
    	String baseClass = stereo.getBaseClass();
    	Iterator it = getStereotypes(ns).iterator();
    	while (it.hasNext()) {
	    Object o = it.next();
	    if (o instanceof MStereotype
		&& ((MStereotype) o).getName() != null
		&& ((MStereotype) o).getName().equals(name)
		&& ((MStereotype) o).getBaseClass() != null
		&& ((MStereotype) o).getBaseClass().equals(baseClass)) {

		return (MStereotype) o;

	    }
    	}
    	return null;
    }

    /**
     * Searches for a stereotype just like the given stereotype in all models 
     * in the current project.
     * The given stereotype can not have its namespace set yet; 
     * otherwise it will be returned itself!
     *
     * TODO: Should it only search for stereotypes owned by the Model object?
     *
     * @param stereo is the given stereotype
     * @return MStereotype
     */
    public MStereotype getStereotype(MStereotype stereo) {
        if (stereo == null) return null;
        String name = stereo.getName();
        String baseClass = stereo.getBaseClass();
        if (name == null || baseClass == null) return null;
        Iterator it2 =
	    ProjectManager.getManager().getCurrentProject()
	        .getModels().iterator();
        while (it2.hasNext()) {
            MModel model = (MModel) it2.next();
            Iterator it = getStereotypes(model).iterator();
            while (it.hasNext()) {
                Object o = it.next();
                if (o instanceof MStereotype
		    && ((MStereotype) o).getName().equals(name)
		    && ((MStereotype) o).getBaseClass().equals(baseClass)) {

                    return (MStereotype) o;

                }
            }
        }
        return null;
    }

    /**
     * @param m the ModelElement
     * @return the meta name of the ModelElement
     */
    public String getMetaModelName(MModelElement m) {
        if (m == null) return null;
        return getMetaModelName(m.getClass());
    }

    /**
     * @param clazz the UML class
     * @return the meta name of the UML class
     */
    protected String getMetaModelName(Class clazz) {
        if (clazz == null) return null;
        String name = clazz.getName();
        name = name.substring(name.lastIndexOf('.') + 2, name.length());
        if (name.endsWith("Impl")) {
            name = name.substring(0, name.lastIndexOf("Impl"));
        }
        return name;
    }

    /**
     * Returns all possible stereotypes for some
     * modelelement. Possible stereotypes are those stereotypes that
     * are owned by the same namespace the modelelement is owned by
     * and that have a baseclass that is the same as the
     * metamodelelement name of the modelelement.
     *
     * @param modelElement is the model element
     * @return Collection
     */
    public Collection getAllPossibleStereotypes(Object modelElement) {
        MModelElement m = (MModelElement) modelElement;
        List ret = new ArrayList();
        if (m == null) return ret;
        Iterator it = getStereotypes().iterator();
        String baseClass = getMetaModelName(m);
        while (it.hasNext()) {
            MStereotype stereo = (MStereotype) it.next();
            if (isValidStereoType(m.getClass(), stereo)) {
                ret.add(stereo);
            }
        }
        return ret;
    }

    /**
     * This function answers the question: 
     * Can we apply the given stereotype to the given class?
     * 
     * @param clazz the class we want to apply the stereotype to 
     * @param stereo the given stereotype
     * @return true if the stereotype may be applied
     */
    private boolean isValidStereoType(Class clazz, Object stereo) {
        if (clazz == null || stereo == null) return false;
        if (getMetaModelName(clazz).equals(ModelFacade.getBaseClass(stereo)))
            return true;
        else {
            if (getMetaModelName(clazz).equals("ModelElement")) return false;
            return isValidStereoType(clazz.getSuperclass(), stereo);
        }
    }

    /**
     * Returns true if the given stereotype has a baseclass that
     * equals the baseclass of the given modelelement or one of the
     * superclasses of the given modelelement.
     *
     * @param theModelElement is the model element
     * @param theStereotype   is the stereotype
     * @return boolean
     */
    public boolean isValidStereoType(Object theModelElement, 
            Object theStereotype) {
        if (theModelElement == null) return false;
	return isValidStereoType(theModelElement.getClass(), theStereotype);
    }

    /**
     * TODO: Should it only search for stereotypes owned by the Model objects?
     *
     * @return the collection of stereotypes in all models 
     *         in the current project
     */
    public Collection getStereotypes() {
        List ret = new ArrayList();
        Project p = ProjectManager.getManager().getCurrentProject();
        Iterator it = p.getModels().iterator();
        while (it.hasNext()) {
            MModel model = (MModel) it.next();
            ret.addAll(getStereotypes(model));
        }
        return ret;
    }

    /**
     * Sets the stereotype of some modelelement. The method also
     * copies a stereotype that is not a part of the current model to
     * the current model.

     *
     * @param modelElement is the model element
     * @param stereotype is the stereotype
     */
    public void setStereoType(Object modelElement, Object stereotype) {
	if (stereotype != null)
	    stereotype =
		ModelManagementHelper.getHelper().getCorrespondingElement(
			stereotype,
			ModelFacade.getModel(modelElement),
			true);
        ModelFacade.setStereotype(
		modelElement,
		stereotype);
    }

    /**
     * Tests if a stereotype is a stereotype with some name and base class.
     *
     * @param object is the stereotype.
     * @param name is the name of the stereotype.
     * @param base is the base class of the stereotype.
     * @return true if object is a stereotype with the desired characteristics.
     */
    public boolean isStereotype(Object object, String name, String base) {
	if (object == null || !(object instanceof MStereotype))
	    return false;

	MStereotype st = (MStereotype) object;
	if (name == null && st.getName() != null)
	    return false;
	if (base == null && st.getBaseClass() != null)
	    return false;

	return name.equals(st.getName()) && base.equals(st.getBaseClass());
    }

    /**
     * Tests if a stereotype is or inherits from a stereotype with some
     * name and base class.
     *
     * @param object is the stereotype.
     * @param name is the name of the stereotype.
     * @param base is the base class of the stereotype.
     * @return true if object is a (descendant of a) stereotype with the
     *	desired characteristics.
     */
    public boolean isStereotypeInh(Object object, String name, String base) {
	if (object == null || !(object instanceof MStereotype))
	    return false;
	if (isStereotype(object, name, base))
	    return true;
	Iterator it = CoreHelper.getHelper().getSupertypes(object).iterator();
	while (it.hasNext()) {
	    if (isStereotypeInh(it.next(), name, base))
		return true;
	}
	return false;
    }
}