source: trunk/autoquest-plugin-uml/src/main/java/de/ugoe/cs/autoquest/plugin/uml/UMLUtils.java @ 1930

//   Copyright 2012 Georg-August-Universität Göttingen, Germany
//
//   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 de.ugoe.cs.autoquest.plugin.uml;

import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.logging.Level;
import java.util.Set;
import java.util.TreeSet;

import org.eclipse.emf.common.util.EList;
import org.eclipse.uml2.uml.Activity;
import org.eclipse.uml2.uml.ActivityEdge;
import org.eclipse.uml2.uml.ActivityNode;
import org.eclipse.uml2.uml.CallConcurrencyKind;
import org.eclipse.uml2.uml.CallEvent;
import org.eclipse.uml2.uml.CallOperationAction;
import org.eclipse.uml2.uml.Comment;
import org.eclipse.uml2.uml.Component;
import org.eclipse.uml2.uml.Connector;
import org.eclipse.uml2.uml.ConnectorEnd;
import org.eclipse.uml2.uml.DataType;
import org.eclipse.uml2.uml.Element;
import org.eclipse.uml2.uml.Expression;
import org.eclipse.uml2.uml.InstanceSpecification;
import org.eclipse.uml2.uml.InstanceValue;
import org.eclipse.uml2.uml.Interaction;
import org.eclipse.uml2.uml.InteractionFragment;
import org.eclipse.uml2.uml.Interface;
import org.eclipse.uml2.uml.Lifeline;
import org.eclipse.uml2.uml.LiteralBoolean;
import org.eclipse.uml2.uml.LiteralInteger;
import org.eclipse.uml2.uml.LiteralReal;
import org.eclipse.uml2.uml.LiteralString;
import org.eclipse.uml2.uml.Message;
import org.eclipse.uml2.uml.MessageOccurrenceSpecification;
import org.eclipse.uml2.uml.MessageSort;
import org.eclipse.uml2.uml.Model;
import org.eclipse.uml2.uml.Operation;
import org.eclipse.uml2.uml.Package;
import org.eclipse.uml2.uml.Parameter;
import org.eclipse.uml2.uml.ParameterDirectionKind;
import org.eclipse.uml2.uml.Port;
import org.eclipse.uml2.uml.PrimitiveType;
import org.eclipse.uml2.uml.Property;
import org.eclipse.uml2.uml.Region;
import org.eclipse.uml2.uml.Slot;
import org.eclipse.uml2.uml.StateMachine;
import org.eclipse.uml2.uml.Stereotype;
import org.eclipse.uml2.uml.Transition;
import org.eclipse.uml2.uml.Trigger;
import org.eclipse.uml2.uml.UMLPackage;
import org.eclipse.uml2.uml.ValueSpecification;
import org.eclipse.uml2.uml.Vertex;

import de.ugoe.cs.autoquest.eventcore.Event;
import de.ugoe.cs.autoquest.plugin.http.SOAPUtils;
import de.ugoe.cs.autoquest.plugin.http.eventcore.SOAPEventType;
import de.ugoe.cs.autoquest.plugin.http.eventcore.SimpleSOAPEventType;
import de.ugoe.cs.autoquest.plugin.uml.eventcore.UMLTransitionType;
import de.ugoe.cs.autoquest.usageprofiles.IStochasticProcess;
import de.ugoe.cs.util.StringTools;
import de.ugoe.cs.util.console.Console;

/**
 * <p>
 * Utilities for working with UML.
 * </p>
 * 
 * @author Steffen Herbold
 */
public class UMLUtils {

    /**
     * In case a multiplicity is defined as *, this value defines the highest one that can be picked
     */
    final static int MAX_MULTIPLICITY = 10;

    /**
     * <p>
     * Method for checking if the information in a usage journal can be mapped to the SUT model. In
     * case this is not possible, the violations are reported.
     * </p>
     * 
     * @param sequences
     *            sequences of the usage journal
     * @param model
     *            SUT model that is validated
     * @param testContextName
     *            name of the test context to be used; if null, the first test context found is used
     * @return number of violations
     */
    public static int validateModelWithLog(Collection<List<Event>> sequences,
                                           Model model,
                                           String testContextName)
    {
        int violationCount = 0;
        Component testContext = fetchTestContext(model, testContextName);
        if (testContext == null) {
            violationCount++;
            if (testContextName == null) {
                Console.traceln(Level.SEVERE, "Could not find any TestContext in the model.");

            }
            else {
                Console.traceln(Level.SEVERE, "Could not find TestContext in the model: " +
                    testContextName);
            }
            Console
                .traceln(Level.SEVERE,
                         "Hint: Check if you have applied the TestContext stereotype correctly in the model.");
            Console.traceln(Level.SEVERE, "Aborting");
            return violationCount;
        }

        // Create list of unique methods calls
        HashMap<String, Set<String>> calledMethods = new HashMap<>();
        for (List<Event> sequence : sequences) {
            for (Event event : sequence) {
                String serviceName = SOAPUtils.getServiceNameFromEvent(event);
                String calledMethod = SOAPUtils.getCalledMethodFromEvent(event);
                if (serviceName != null) {
                    Set<String> curCalledMethods = calledMethods.get(serviceName);
                    if (curCalledMethods == null) {
                        curCalledMethods = new TreeSet<>();
                        calledMethods.put(serviceName, curCalledMethods);
                    }
                    curCalledMethods.add(calledMethod);
                }
            }
        }

        Console.traceln(Level.INFO,
                        "Found the following services and operations in the usage data: ");
        for (Entry<String, Set<String>> entry : calledMethods.entrySet()) {
            Console.traceln(Level.INFO, "\tService \"" + entry.getKey() + "\": ");
            for (String method : entry.getValue()) {
                Console.traceln(Level.INFO, "\t\t" + method);
            }
        }

        // fetch all SUTs and TestComponents
        HashMap<String, Property> properties = new HashMap<>();
        for (Property property : fetchAllSUTProperties(testContext)) {
            properties.put(property.getName(), property);
        }
        for (Property property : fetchAllTestComponentProperties(testContext)) {
            properties.put(property.getName(), property);
        }
        Console.traceln(Level.INFO, "Found the following services in the TestConfiguration:");
        for (Entry<String, Property> entry : properties.entrySet()) {
            Console.traceln(Level.INFO, "\t" + entry.getKey());
        }

        for (Entry<String, Set<String>> entry : calledMethods.entrySet()) {
            String serviceName = entry.getKey();
            Console.traceln(Level.INFO, "Checking service: " + serviceName);
            Set<String> methodNames = entry.getValue();
            Property property = properties.get(serviceName);
            if (property == null) {
                violationCount++;
                Console.traceln(Level.SEVERE, "\tCould not find property for service: " +
                    serviceName);
                Console
                    .traceln(Level.SEVERE,
                             "\tHint: Check service name map and/or model if the service is present and spelled correctly.");
                Console
                    .traceln(Level.SEVERE,
                             "\tHint: Check if the SUT/TestComponent stereotype has been applied correctly in this TestContext.");
            }
            else {
                Set<Interface> interfaces = getRealizedInterfacesFromProperty(property);
                if (interfaces.isEmpty()) {
                    violationCount++;
                    Console
                        .traceln(Level.SEVERE,
                                 "\tCould not find any interfaces implementing the property for service: " +
                                     serviceName);
                    Console
                        .traceln(Level.SEVERE,
                                 "\tHint: Check if the property correctly realizes the interfaces in the model.");
                }
                else {
                    Console.traceln(Level.INFO,
                                    "\tFound the following realized interfaces for the service \"" +
                                        serviceName + "\": ");
                    for (Interface intface : interfaces) {
                        Console.traceln(Level.INFO, "\t" + intface.getName());
                        for (Operation operation : intface.getAllOperations()) {
                            Console.traceln(Level.INFO, "\t\t" + operation.getName());
                        }
                    }
                    for (String methodName : methodNames) {
                        boolean methodFound = false;
                        for (Interface intface : interfaces) {
                            if (getOperationFromName(intface.getOperations(), methodName) != null) {
                                // interface found
                                Console.traceln(Level.INFO, "\tMethod " + methodName +
                                    " found in interface " + intface.getName());
                                methodFound = true;
                            }
                        }
                        if (!methodFound) {
                            violationCount++;
                            Console.traceln(Level.SEVERE, "\tCould not find operation: " +
                                methodName);
                        }
                    }
                }
            }
        }
        return violationCount;
    }

    /**
     * <p>
     * Creates a sequence of events with {@link UMLTransitionType} as event type from a given
     * sequence of events with the {@link SOAPEventType} or {@link SimpleSOAPEventType}, by matching
     * the sequences to a state machine.
     * </p>
     * 
     * @param sequence
     *            SOAP sequences
     * @param stateMachine
     *            the state machine
     * @return create UML sequences
     */
    public static List<Event> createUMLTransitionSequence(List<Event> sequence,
                                                          StateMachine stateMachine)
    {
        List<List<Transition>> matchingSequences =
            determineMatchingTransitionSequences(sequence, stateMachine);

        if (matchingSequences.size() != 1) {
            throw new RuntimeException("no unique match found; " + matchingSequences.size() +
                " matches");
        }
        List<Event> umlEventSequence = new LinkedList<>();
        for (Transition transition : matchingSequences.get(0)) {
            umlEventSequence.add(new Event(new UMLTransitionType(transition)));
        }
        return umlEventSequence;
    }

    /**
     * <p>
     * Uses a sequences of events with the {@link UMLTransitionType} to determine the transition
     * probabilities for the state machine.
     * </p>
     * 
     * @param sequences
     *            UML sequences
     * @param stateMachine
     *            state machine to be converted to a usage profile
     */
    public static void convertStateMachineToUsageProfile(Collection<List<Event>> sequences,
                                                         StateMachine stateMachine)
    {
        // create state->outgoings hashmap
        Map<Vertex, Map<Transition, Integer>> stateMap = new HashMap<>();
        for (Region region : stateMachine.getRegions()) {
            for (Vertex state : region.getSubvertices()) {
                stateMap.put(state, new HashMap<Transition, Integer>());
            }
        }

        // create counters for each transition
        for (List<Event> sequence : sequences) {
            for (Event event : sequence) {
                if (event.getType() instanceof UMLTransitionType) {
                    Transition transition = ((UMLTransitionType) event.getType()).getTransition();
                    Map<Transition, Integer> transitionMap = stateMap.get(transition.getSource());
                    Integer value = transitionMap.get(transition);
                    if (value == null) {
                        value = 0;
                    }
                    transitionMap.put(transition, value + 1);
                }
                else {
                    throw new RuntimeException(
                                               "Wrong event type. Only UMLTransitionType supported but was: " +
                                                   event.getType().getClass().getName());
                }
            }
        }

        // calculate probabilities
        for (Region region : stateMachine.getRegions()) {
            for (Vertex state : region.getSubvertices()) {
                Map<Transition, Integer> transitionMap = stateMap.get(state);
                int totalCount = 0;
                for (Entry<Transition, Integer> entry : transitionMap.entrySet()) {
                    totalCount += entry.getValue();
                }
                if (totalCount != 0) {
                    for (Transition transition : state.getOutgoings()) {
                        double prob = 0.0d;
                        if (transitionMap.containsKey(transition)) {
                            prob = ((double) transitionMap.get(transition)) / totalCount;
                        }
                        Comment comment = transition.createOwnedComment();
                        comment.setBody("" + prob);
                    }
                }
                else {
                    // system has never been in this state, all transitions equally likely
                    int numOutgoings = state.getOutgoings().size();
                    for (Transition transition : state.getOutgoings()) {
                        Comment comment = transition.createOwnedComment();
                        comment.setBody("" + (1.0d / numOutgoings));
                    }
                }
            }
        }
    }

    /**
     * <p>
     * Determines all matching {@link Transition} sequences in a state machine for a given sequence
     * of SOAP events.
     * </p>
     * 
     * @param sequence
     *            SOAP sequence
     * @param stateMachine
     *            the state machine
     * @return all matching {@link Transition} sequences
     */
    public static List<List<Transition>> determineMatchingTransitionSequences(List<Event> sequence,
                                                                              StateMachine stateMachine)
    {
        EList<Region> regions = stateMachine.getRegions();
        EList<Vertex> states = null;
        for (Region region : regions) {
            if (states == null) {
                states = region.getSubvertices();
            }
            else {
                states.addAll(region.getSubvertices());
            }
        }
        List<Transition> allTransitions = new LinkedList<>();
        for (Vertex state : states) {
            allTransitions.addAll(state.getOutgoings());
        }

        List<List<Transition>> matchingSequences = null;
        List<Transition> currentTransitions = null;

        // first, we try to find a single unique transition that we can match using the method name
        for (Iterator<Event> eventIterator = sequence.iterator(); eventIterator.hasNext();) {
            Event event = eventIterator.next();
            if (matchingSequences == null) {
                matchingSequences = new LinkedList<>();
                List<Transition> initialMatches = matchTransitions(allTransitions, event);
                for (Transition transition : initialMatches) {
                    List<Transition> candidate = new LinkedList<>();
                    candidate.add(transition);
                    matchingSequences.add(candidate);
                }
                currentTransitions = initialMatches;
            }
            else {
                List<List<Transition>> nextMatchingSequences = new LinkedList<>();
                List<Transition> nextCurrentTransitions = new LinkedList<>();
                Iterator<Transition> currentTransitionIterator = currentTransitions.iterator();
                Iterator<List<Transition>> currentMatchingSequencesIterator =
                    matchingSequences.iterator();
                while (currentTransitionIterator.hasNext()) {
                    Transition currentTransition = currentTransitionIterator.next();
                    List<Transition> currentMatch = currentMatchingSequencesIterator.next();

                    List<Transition> matches =
                        matchTransitions(currentTransition.getTarget().getOutgoings(), event);
                    if (matches.isEmpty()) {
                        throw new RuntimeException("no matches found");
                    }
                    for (Transition matchingTransition : matches) {
                        List<Transition> candidate = new LinkedList<>(currentMatch);
                        candidate.add(matchingTransition);
                        nextMatchingSequences.add(candidate);
                        nextCurrentTransitions.add(matchingTransition);
                    }
                }
                matchingSequences = nextMatchingSequences;
                currentTransitions = nextCurrentTransitions;
            }
        }
        return matchingSequences;
    }

    /**
     * <p>
     * Extends a given model with an interaction that represents an observed sequence.
     * </p>
     * 
     * @param sequence
     *            sequence that is added as sequence diagram
     * @param model
     *            UML model to which the interaction is added
     * @param interactionName
     *            name of the interaction
     * @param testContextName
     *            Name of the test context that should be used. If this value is null, the first
     *            test context found is used.
     */
    public static Interaction createInteractionFromEventSequence(List<Event> sequence,
                                                                 Model model,
                                                                 String interactionName,
                                                                 String testContextName)
    {
        final Component testContext = fetchTestContext(model, testContextName);
        if (testContext == null) {
            throw new RuntimeException("Could not find any test context in the model");
        }

        final Operation operation = testContext.createOwnedOperation(interactionName, null, null);
        operation.applyStereotype(UTPUtils.getTestCaseStereotype(model));

        final Interaction interaction =
            (Interaction) testContext.createPackagedElement(interactionName + "_Impl",
                                                            UMLPackage.Literals.INTERACTION);
        operation.getMethods().add(interaction);

        // create lifelines
        Lifeline userLifeline = null;

        for (Property property : fetchAllSUTProperties(testContext)) {
            String serviceName = property.getName();
            Lifeline targetLifeline = interaction.createLifeline(serviceName);
            targetLifeline.setRepresents(property);
        }
        for (Property property : fetchAllTestComponentProperties(testContext)) {
            // TODO check if this is still required
            if (userLifeline != null) {
                throw new RuntimeException(
                                           "TestContext must only have one TestComponent for the application of usage-based testing.");
            }
            userLifeline = interaction.createLifeline(property.getName());
            userLifeline.setRepresents(property);
        }

        if (userLifeline == null) {
            throw new RuntimeException("No TestComponent found, could not create user lifeline.");
        }
        if (interaction.getLifelines().size() < 2) {
            throw new RuntimeException("Fewer than two lifelines created. No SUT found.");
        }

        int i = 0;
        for (Event event : sequence) {
            if (!(event.equals(Event.STARTEVENT) || event.equals(Event.ENDEVENT))) {
                String serviceName = SOAPUtils.getServiceNameFromEvent(event);
                String methodName = SOAPUtils.getCalledMethodFromEvent(event);
                String clientName = SOAPUtils.getClientNameFromEvent(event);
                String prefix = interactionName + ":" + i + ":" + methodName + "_";
                // determine lifelines
                Lifeline msgTargetLifeline;
                Lifeline msgSourceLifeline;

                msgSourceLifeline = interaction.getLifeline(clientName);
                msgTargetLifeline = interaction.getLifeline(serviceName);

                if (msgSourceLifeline == null) {
                    throw new RuntimeException(
                                               "Error creating message: could not determine source lifeline for component: " +
                                                   clientName);
                }
                if (msgTargetLifeline == null) {
                    throw new RuntimeException(
                                               "Error creating message: could not determine target lifeline for component: " +
                                                   serviceName);
                }
                // determine correct target interface
                Set<Interface> targetInterfaces =
                    getRealizedInterfacesFromProperty((Property) msgTargetLifeline.getRepresents());
                if (targetInterfaces.isEmpty()) {
                    throw new RuntimeException("no interface associated with the property " +
                        msgTargetLifeline.getRepresents().getName());
                }
                Interface targetInterface = null;
                for (Interface intface : targetInterfaces) {
                    if (getOperationFromName(intface.getOperations(), methodName) != null) {
                        // interface found
                        targetInterface = intface;
                        break;
                    }
                }
                if (targetInterface == null) {
                    StringBuilder errStrBuilder = new StringBuilder();
                    errStrBuilder
                        .append("Error creating message: operation not found in the implementing interfaces (");
                    Iterator<Interface> iter = targetInterfaces.iterator();
                    while (iter.hasNext()) {
                        String interfaceName = iter.next().getName();
                        errStrBuilder.append(interfaceName);
                        if (iter.hasNext()) {
                            errStrBuilder.append(",");
                        }
                        else {
                            errStrBuilder.append("): " + methodName);
                        }
                    }
                    throw new RuntimeException(errStrBuilder.toString());
                }

                Operation calledOperation =
                    getOperationFromName(targetInterface.getOperations(), methodName);

                // setup for both SYNCH and ASYNCH calls
                MessageOccurrenceSpecification callSendFragment =
                    (MessageOccurrenceSpecification) interaction.createFragment(prefix +
                        "callSendFragment", UMLPackage.Literals.MESSAGE_OCCURRENCE_SPECIFICATION);
                MessageOccurrenceSpecification callRecvFragment =
                    (MessageOccurrenceSpecification) interaction.createFragment(prefix +
                        "callRecvFragment", UMLPackage.Literals.MESSAGE_OCCURRENCE_SPECIFICATION);

                callSendFragment.setCovered(msgSourceLifeline);
                callRecvFragment.setCovered(msgTargetLifeline);

                // get connector
                Connector connector = inferConnector(msgSourceLifeline, msgTargetLifeline);

                // create call
                Message callMessage = interaction.createMessage(prefix + "call");
                callMessage.setSignature(calledOperation);
                setCallMessageParameters(callMessage, calledOperation, event, prefix);
                callMessage.setConnector(connector);
                callMessage.setSendEvent(callSendFragment);
                callMessage.setReceiveEvent(callRecvFragment);
                callSendFragment.setMessage(callMessage);
                callRecvFragment.setMessage(callMessage);

                boolean asynch = false;
                if (calledOperation.getConcurrency() == CallConcurrencyKind.CONCURRENT_LITERAL) {
                    asynch = true;
                }
                if (asynch) {
                    // Create ASYNCH call
                    callMessage.setMessageSort(MessageSort.ASYNCH_CALL_LITERAL);
                }
                else {
                    // SYNCH call
                    callMessage.setMessageSort(MessageSort.SYNCH_CALL_LITERAL);

                    // setup reply and behavior execution specifications
                    MessageOccurrenceSpecification replySendFragment =
                        (MessageOccurrenceSpecification) interaction
                            .createFragment(prefix + "replySendFragment",
                                            UMLPackage.Literals.MESSAGE_OCCURRENCE_SPECIFICATION);
                    MessageOccurrenceSpecification replyRecvFragment =
                        (MessageOccurrenceSpecification) interaction
                            .createFragment(prefix + "replyRecvFragment",
                                            UMLPackage.Literals.MESSAGE_OCCURRENCE_SPECIFICATION);

                    replySendFragment.setCovered(msgTargetLifeline);
                    replyRecvFragment.setCovered(msgSourceLifeline);

                    /*
                     * BehaviorExecutionSpecification sourceBehaviorExecutionSpecification =
                     * (BehaviorExecutionSpecification) interaction .createFragment(":" + methodName
                     * + "_sourceBhvExecSpec",
                     * UMLPackage.Literals.BEHAVIOR_EXECUTION_SPECIFICATION);
                     * BehaviorExecutionSpecification targetBehaviorExecutionSpecification =
                     * (BehaviorExecutionSpecification) interaction .createFragment(":" + methodName
                     * + "_targetBhvExecSpec",
                     * UMLPackage.Literals.BEHAVIOR_EXECUTION_SPECIFICATION);
                     * 
                     * sourceBehaviorExecutionSpecification.setStart(callSendFragment);
                     * sourceBehaviorExecutionSpecification.setFinish(replyRecvFragment);
                     * targetBehaviorExecutionSpecification.setStart(callRecvFragment);
                     * targetBehaviorExecutionSpecification.setFinish(replySendFragment);
                     */

                    // create reply
                    Message replyMessage = interaction.createMessage(prefix + "_reply");
                    replyMessage.setMessageSort(MessageSort.REPLY_LITERAL);
                    replyMessage.setSignature(calledOperation);
                    setReplyMessageParameters(replyMessage, calledOperation);
                    replyMessage.setConnector(connector);
                    replyMessage.setSendEvent(replySendFragment);
                    replyMessage.setReceiveEvent(replyRecvFragment);
                    replySendFragment.setMessage(replyMessage);
                    replyRecvFragment.setMessage(replyMessage);
                }

                i++;
            }
        }
        return interaction;
    }

    /**
     * <p>
     * Calculates the usage score of an interaction as the logsum of the event probabilities
     * multiplied with the length of the interaction.
     * </p>
     * 
     * @param interaction
     *            interaction for which the score is calculated
     * @param usageProfile
     *            usage profile used for the calculation
     * @return calculated usage score
     */
    public static double calculateUsageScore(Interaction interaction,
                                             IStochasticProcess usageProfile)
    {
        double usageScore = 0.0d;
        EList<InteractionFragment> interactionFragments = interaction.getFragments();
        List<Event> eventSequence = new LinkedList<>();
        eventSequence.add(Event.STARTEVENT);
        for (InteractionFragment interactionFragment : interactionFragments) {
            if (interactionFragment instanceof MessageOccurrenceSpecification) {
                Message message =
                    ((MessageOccurrenceSpecification) interactionFragment).getMessage();
                if (message.getReceiveEvent().equals(interactionFragment) && isCallMessage(message))
                {
                    String clientName =
                        ((MessageOccurrenceSpecification) message.getSendEvent()).getCovereds()
                            .get(0).getName();
                    String serviceName =
                        ((MessageOccurrenceSpecification) message.getReceiveEvent()).getCovereds()
                            .get(0).getName();
                    String methodName = message.getSignature().getName();
                    eventSequence.add(new Event(new SimpleSOAPEventType(methodName, serviceName,
                                                                        clientName, null)));
                }
            }
        }
        eventSequence.add(Event.ENDEVENT);
        double prob = usageProfile.getLogSum(eventSequence);
        usageScore = eventSequence.size() * prob;

        return usageScore;
    }

    /**
     * <p>
     * Extends the given model with an activity for usage-based scheduling of the test cases.
     * </p>
     * 
     * @param model
     *            model to be extended
     * @param usageProfile
     *            usage profile used as foundation
     */
    public static void createScheduling(Model model,
                                        IStochasticProcess usageProfile,
                                        String testContextName)
    {
        final Component testContext = fetchTestContext(model, testContextName);
        if (testContext == null) {
            throw new RuntimeException("Could not find any test context in the model");
        }

        Map<Operation, Double> usageScoreMapUnsorted = new HashMap<>();

        // first, we determine all test cases and calculate their usage scores
        final Stereotype utpTestCase = UTPUtils.getTestCaseStereotype(model);
        for (Operation operation : testContext.getAllOperations()) {
            if (operation.getAppliedStereotypes().contains(utpTestCase) &&
                !operation.getMethods().isEmpty())
            {
                Interaction interaction = (Interaction) operation.getMethods().get(0);
                usageScoreMapUnsorted
                    .put(operation, calculateUsageScore(interaction, usageProfile));
            }
        }
        Map<Operation, Double> usageScoreMapSorted = sortByValue(usageScoreMapUnsorted);

        // now we create the scheduling
        Activity schedulingActivity =
            (Activity) testContext.createOwnedBehavior("UsageBasedScheduling",
                                                       UMLPackage.Literals.ACTIVITY);
        testContext.setClassifierBehavior(schedulingActivity);

        ActivityNode startNode =
            schedulingActivity.createOwnedNode("final", UMLPackage.Literals.INITIAL_NODE);
        ActivityNode finalNode =
            schedulingActivity.createOwnedNode("final", UMLPackage.Literals.ACTIVITY_FINAL_NODE);

        ActivityNode currentOperationNode = startNode;

        for (Entry<Operation, Double> entry : usageScoreMapSorted.entrySet()) {
            Operation operation = entry.getKey();
            CallOperationAction nextOperationNode =
                (CallOperationAction) schedulingActivity
                    .createOwnedNode(operation.getName(), UMLPackage.Literals.CALL_OPERATION_ACTION);
            nextOperationNode.setOperation(operation);

            ActivityEdge edge =
                schedulingActivity.createEdge(currentOperationNode.getName() + "_to_" +
                    nextOperationNode.getName(), UMLPackage.Literals.CONTROL_FLOW);
            edge.setSource(currentOperationNode);
            edge.setTarget(nextOperationNode);

            currentOperationNode = nextOperationNode;
        }

        ActivityEdge edge =
            schedulingActivity
                .createEdge(currentOperationNode.getName() + "_to_" + finalNode.getName(),
                            UMLPackage.Literals.CONTROL_FLOW);
        edge.setSource(currentOperationNode);
        edge.setTarget(finalNode);
    }

    /**
     * <p>
     * Fetches an operation using only its name from a list of operations. Returns the first match
     * found or null if no match is found.
     * </p>
     * 
     * @param operations
     *            list of operations
     * @param name
     *            name of the operation
     * @return first matching operation; null if no match is found
     */
    private static Operation getOperationFromName(EList<Operation> operations, String name) {
        if (name == null) {
            throw new IllegalArgumentException("name of the operation must not be null");
        }
        if (operations != null) {
            for (Operation operation : operations) {
                if (operation.getName() != null && operation.getName().equals(name)) {
                    return operation;
                }
            }
        }
        return null;
    }

    /**
     * <p>
     * Determines which transitions match a given {@link SOAPEventType}.
     * </p>
     * 
     * @param transitions
     *            the transitions
     * @param eventType
     *            the SOAP event
     * @return matching transitions
     */
    private static List<Transition> matchTransitions(List<Transition> transitions, Event event) {
        String eventService = SOAPUtils.getServiceNameFromEvent(event);
        String eventMethod = SOAPUtils.getCalledMethodFromEvent(event);

        Map<Interface, String> interfaceServiceMap =
            createInterfaceServiceMap(transitions.get(0).getModel());

        List<Transition> matching = new LinkedList<>();
        for (Transition transition : transitions) {
            EList<Trigger> triggers = transition.getTriggers();
            if (triggers.size() == 1) {
                if (triggers.get(0).getEvent() instanceof CallEvent) {
                    CallEvent callEvent = (CallEvent) triggers.get(0).getEvent();
                    String transitionMethod = callEvent.getOperation().getName();
                    String transitionService =
                        interfaceServiceMap.get(callEvent.getOperation().getInterface());
                    
                    if (eventMethod.equals(transitionMethod) &&
                        eventService.equals(transitionService))
                    {
                        matching.add(transition);
                    }
                }
            } else {
                throw new RuntimeException("only one trigger of type CallEvent per transition allowed: " + transition.getName());
            }

        }
        return matching;
    }

    /**
     * <p>
     * Fetches all realized interfaces from the type of a UML {@link Property} (i.e.,
     * property.getType()). If no interfaces are realized, an empty set is returned.
     * </p>
     * 
     * @param property
     *            property, of the whose realized interfaces of the type are determined
     * @return realized interfaces
     */
    private static Set<Interface> getRealizedInterfacesFromProperty(Property property) {
        return getRealizedInterfaceFromComponent((Component) property.getType());
    }

    /**
     * <p>
     * Fetches all realized interfaces from a UML {@link Component}. If no interfaces are realized,
     * an empty set is returned.
     * </p>
     * 
     * @param comp
     *            component whose realized interfaces are determined
     * @return realized interfaces
     */
    private static Set<Interface> getRealizedInterfaceFromComponent(Component component) {
        Set<Interface> interfaces = new HashSet<>();
        // Interface myInterface = null;
        for (Property property : component.getAttributes()) {
            if (property instanceof Port) {
                Port port = (Port) property;
                if (!port.isConjugated()) {
                    interfaces.addAll(port.getProvideds());
                }
            }
        }
        return interfaces;
    }

    /**
     * <p>
     * Determines searches within a {@link Package} for a component to which the UTP TestContext
     * stereotype is applied.
     * <ul>
     * <li>If no testContextName is provided, the first test context found is returned.</li>
     * <li>In case no test context is found, null is returned.</li>
     * </p>
     * 
     * @param pkg
     *            package where the test context is being locked for
     * @param testContextName
     *            name of the test context; in case no test name is specified, use null and not the
     *            empty String.
     * @return {@link Component} to which the TestContext stereotype is applied
     */
    private static Component fetchTestContext(final Package pkg, final String testContextName) {
        List<Component> testContexts = fetchAllTestContexts(pkg);
        if (testContexts.isEmpty()) {
            return null;
        }
        if (testContextName != null) {
            for (Component testContext : testContexts) {
                if (testContextName.equals(testContext.getName())) {
                    return testContext;
                }
            }
            return null;
        }
        else {
            return testContexts.get(0);
        }
    }

    /**
     * <p>
     * Retrieves all UML {@link Component}s to which the UTP TestContext stereotype is applied from
     * a package. This method calls itself recursively to include all components contained in
     * sub-packages.
     * </p>
     * <p>
     * In case no test context is found, an empty list is returned.
     * </p>
     * 
     * @param pkg
     *            package from which the test contexts are retrieved
     * @return {@link List} of test contexts
     */
    private static List<Component> fetchAllTestContexts(final Package pkg) {
        final Stereotype utpTestContext = UTPUtils.getTestContextStereotype(pkg.getModel());
        final List<Component> testContexts = new LinkedList<>();
        for (Element element : pkg.getOwnedElements()) {
            if (element instanceof Package) {
                testContexts.addAll(fetchAllTestContexts((Package) element));
            }
            if (element instanceof Component &&
                element.getAppliedStereotypes().contains(utpTestContext))
            {
                testContexts.add((Component) element);
            }
        }
        return testContexts;
    }

    /**
     * <p>
     * Retrieves all properties that represent a UTP TestComponent from a test context.
     * </p>
     * 
     * @param testContext
     *            test context from which the properties are retrieved
     * @return properties that represent test components
     */
    private static Set<Property> fetchAllTestComponentProperties(final Component testContext) {
        // fetch all SUTs and TestComponents
        final Stereotype utpTestComponent =
            UTPUtils.getTestComponentStereotype(testContext.getModel());
        final Set<Property> properties = new HashSet<>();
        for (Property property : testContext.getAllAttributes()) {
            if (property.getType().getAppliedStereotypes().contains(utpTestComponent)) {
                properties.add(property);
            }
        }
        return properties;
    }

    /**
     * <p>
     * Retrieves all properties that represent a UTP SUT from a test context.
     * </p>
     * 
     * @param testContext
     *            test context from which the properties are retrieved
     * @return properties that represent the SUTs
     */
    private static Set<Property> fetchAllSUTProperties(final Component testContext) {
        // fetch all SUTs and TestComponents
        final Stereotype utpSUT = UTPUtils.getSUTStereotype(testContext.getModel());
        final Set<Property> properties = new HashSet<>();
        for (Property property : testContext.getAllAttributes()) {
            if (property.getAppliedStereotypes().contains(utpSUT)) {
                properties.add(property);
            }
        }
        return properties;
    }

    /**
     * <p>
     * Infers connector between two lifelines.
     * </p>
     * <p>
     * TODO: Currently assumes only one connector between two lifelines possible. This assumption is
     * invalid as soon as there are two ports that connect the same two properties.
     * </p>
     * 
     * @param msgSourceLifeline
     *            source lifeline of the message
     * @param targetAttributes
     *            target lifeline of the message
     */
    private static Connector inferConnector(Lifeline msgSourceLifeline, Lifeline msgTargetLifeline)
    {
        EList<Property> userAttributes =
            ((Component) msgSourceLifeline.getRepresents().getType()).getAttributes();
        EList<Property> targetAttributes =
            ((Component) msgTargetLifeline.getRepresents().getType()).getAttributes();
        for (Property userAttribute : userAttributes) {
            if (userAttribute instanceof Port) {
                EList<ConnectorEnd> userEnds = ((Port) userAttribute).getEnds();
                for (ConnectorEnd userEnd : userEnds) {
                    Connector userConnector = (Connector) userEnd.eContainer();
                    for (Property targetAttribute : targetAttributes) {
                        if (targetAttribute instanceof Port) {
                            EList<ConnectorEnd> targetEnds = ((Port) targetAttribute).getEnds();
                            for (ConnectorEnd targetEnd : targetEnds) {
                                Connector targetConnector = (Connector) targetEnd.eContainer();
                                if (targetConnector == userConnector) {
                                    return targetConnector;
                                }
                            }
                        }
                    }
                }
            }
        }
        return null;
    }

    /**
     * <p>
     * Creates a map that maps the interfaces to the properties, i.e., services that they are
     * represented by.
     * </p>
     * <p>
     * TODO: currently assumes that each interfaces is only realized by one property
     * </p>
     * 
     * @param model
     *            model for which the interface->service map is created
     * @return the map
     */
    private static Map<Interface, String> createInterfaceServiceMap(Model model) {
        Map<Interface, String> interfaceServiceMap = new HashMap<>();
        List<Component> testContexts = fetchAllTestContexts(model.getModel());
        for (Component testContext : testContexts) {
            for (Property property : fetchAllSUTProperties(testContext)) {
                for (Interface intface : getRealizedInterfacesFromProperty(property)) {
                    interfaceServiceMap.put(intface, property.getName());
                }
            }
            for (Property property : fetchAllTestComponentProperties(testContext)) {
                for (Interface intface : getRealizedInterfacesFromProperty(property)) {
                    interfaceServiceMap.put(intface, property.getName());
                }
            }
        }
        return interfaceServiceMap;
    }

    /**
     * <p>
     * Sets values for the parameters of a call message. The values are, if possible, inferred from
     * the event that is provided.
     * </p>
     * 
     * @param callMessage
     *            call message for which the parameters are set
     * @param calledOperation
     *            operation that is called by the message
     * @param event
     *            event that provides the parameters; in case of null, default values are assumed
     * @param prefix
     *            prefix of the call message; used to create good warnings and debugging information
     */
    private static void setCallMessageParameters(Message callMessage,
                                                 Operation calledOperation,
                                                 Event event,
                                                 String prefix)
    {
        org.w3c.dom.Element requestBody = SOAPUtils.getSoapRequestBodyFromEvent(event);
        Package instSpecPkg = null;

        // Set parameters of operation
        for (Parameter param : calledOperation.getOwnedParameters()) {
            if (instSpecPkg == null) {
                instSpecPkg = getOrCreateInstanceSpecificationPackage(param.getModel(), event);
            }

            String path = calledOperation.getName() + ":" + param.getName();
            Expression argument =
                (Expression) callMessage.createArgument(param.getName(), param.getType(),
                                                        UMLPackage.Literals.EXPRESSION);

            if (isInParameter(param)) {
                if (param.getType() instanceof DataType) {
                    List<org.w3c.dom.Element> paramNodes =
                        SOAPUtils.getMatchingChildNode(param.getType().getName(), requestBody);
                    int multiplicityChosen = paramNodes.size();

                    if (multiplicityChosen == 0 && param.getLower() > 0) {
                        Console.traceln(Level.WARNING,
                                        "required attribute not found in SOAP message: " + path);
                        Console
                            .traceln(Level.WARNING,
                                     "setting default values for this attribute and all its children");
                        Console.traceln(Level.FINE, "XML structure of path:" + StringTools.ENDLINE +
                            SOAPUtils.getSerialization(requestBody));
                        multiplicityChosen = param.getLower();
                    }
                    for (int i = 0; i < multiplicityChosen; i++) {
                        org.w3c.dom.Element paramNode = null;
                        if (!paramNodes.isEmpty()) {
                            paramNode = paramNodes.get(i);
                        }
                        InstanceSpecification instSpec =
                            createInstanceSpecification((DataType) param.getType(), instSpecPkg,
                                                        prefix, paramNode, path);

                        InstanceValue value =
                            (InstanceValue) argument
                                .createOperand(null, param.getType(),
                                               UMLPackage.Literals.INSTANCE_VALUE);
                        value.setInstance(instSpec);
                    }
                }
                else if (param.getType() instanceof PrimitiveType) {
                    createOperandPrimitiveType(param, argument, requestBody, path);
                }
            }
            else {
                // set literalNull for out and return parameters
                argument.createOperand(null, param.getType(), UMLPackage.Literals.LITERAL_NULL);
            }
        }
    }

    /**
     * <p>
     * Creates an {@link InstanceSpecification} for a data type in the given package. The values are
     * inferred, if possible, from the DOM node. The prefix and the path are used for naming the
     * instance specification and to provide good warnings and debug information in case of
     * problems.
     * </p>
     * 
     * @param type
     *            DataType for which the {@link InstanceSpecification} is created
     * @param pkg
     *            package in which the {@link InstanceSpecification} is created
     * @param prefix
     *            prefix used for naming the {@link InstanceSpecification}
     * @param currentNode
     *            node of a DOM from which values are inferred
     * @param path
     *            used for warnings and debug information
     * @return {@link InstanceSpecification} for the given type
     */
    private static InstanceSpecification createInstanceSpecification(DataType type,
                                                                     Package pkg,
                                                                     String prefix,
                                                                     org.w3c.dom.Element currentNode,
                                                                     String path)
    {
        if ("".equals(path)) {
            path = type.getName();
        }

        InstanceSpecification instSpec =
            (InstanceSpecification) pkg
                .createPackagedElement(prefix + "instspec_" + type.getName(),
                                       UMLPackage.Literals.INSTANCE_SPECIFICATION);
        instSpec.getClassifiers().add(type);
        for (Property prop : type.getAllAttributes()) {
            if (prop.getType() instanceof PrimitiveType) {
                createSlotPrimitiveType(instSpec, prop, currentNode, path);
            }
            else if (prop.getType() instanceof DataType) {
                List<org.w3c.dom.Element> attributeNodes = null;
                int multiplicityChosen = 0;
                if (currentNode != null) {
                    attributeNodes = SOAPUtils.getMatchingChildNode(prop.getName(), currentNode);
                    multiplicityChosen = attributeNodes.size();
                }

                if (multiplicityChosen == 0 && prop.getLower() > 0) {
                    if (currentNode != null) {
                        Console.traceln(Level.WARNING,
                                        "required attribute not found in SOAP message: " + path +
                                            "." + prop.getName());
                        Console
                            .traceln(Level.WARNING,
                                     "setting default values for this attribute and all its children");
                        Console.traceln(Level.FINE, "XML structure of path:" + StringTools.ENDLINE +
                            SOAPUtils.getSerialization(currentNode));
                    }
                    multiplicityChosen = prop.getLower();
                }
                for (int i = 0; i < multiplicityChosen; i++) {
                    org.w3c.dom.Element attributeNode = null;
                    if (attributeNodes != null && !attributeNodes.isEmpty()) {
                        attributeNode = attributeNodes.get(i);
                    }

                    Slot slot = instSpec.createSlot();
                    slot.setDefiningFeature(prop);

                    InstanceValue value =
                        (InstanceValue) slot.createValue(prop.getName() + "_" + i, prop.getType(),
                                                         UMLPackage.Literals.INSTANCE_VALUE);
                    value.setInstance(createInstanceSpecification((DataType) prop.getType(), pkg,
                                                                  prefix, attributeNode, path +
                                                                      "." + prop.getName()));
                }
            }
            else {
                Console.traceln(Level.SEVERE, "property neither DataType nor PrimitiveType: " +
                    prop.getType());
                // TODO abort?
            }
        }
        return instSpec;
    }

    /**
     * <p>
     * Gets or creates a {@link Package} for {@link InstanceSpecification} created by the
     * usage-based testing. Each service gets its own sub-package within a package called
     * UBT_InstanceSpecifications. "
     * </p>
     * 
     * @param model
     *            model in which the package is generated
     * @param event
     *            event from which the service name is inferred
     * @return package for the {@link InstanceSpecification}s
     */
    private static Package getOrCreateInstanceSpecificationPackage(Model model, Event event) {
        String pkgUBTInstSpecs = "UBT_InstanceSpecifications";
        Package ubtInstSpecPkg = (Package) model.getOwnedMember(pkgUBTInstSpecs);
        if (ubtInstSpecPkg == null) {
            ubtInstSpecPkg =
                (Package) model.createPackagedElement(pkgUBTInstSpecs, UMLPackage.Literals.PACKAGE);
        }
        String serviceName = SOAPUtils.getServiceNameFromEvent(event);
        Package serviceInstSpecPkg = (Package) ubtInstSpecPkg.getOwnedMember(serviceName);
        if (serviceInstSpecPkg == null) {
            serviceInstSpecPkg =
                (Package) ubtInstSpecPkg.createPackagedElement(serviceName,
                                                               UMLPackage.Literals.PACKAGE);
        }
        return serviceInstSpecPkg;
    }

    /**
     * <p>
     * Creates an operand that defines a {@link PrimitiveType}.
     * </p>
     * <p>
     * TODO: Currently does nothing in case of multiplicity 0. I am not sure if, in that case, one
     * has to define LiteralNull instead.
     * </p>
     * 
     * @param param
     *            parameter for which the operand is created
     * @param argument
     *            argument to which the operand is added
     * @param currentNode
     *            DOM node from which is value for the operand is inferred
     * @param path
     *            used for warnings and debug information
     */
    private static void createOperandPrimitiveType(Parameter param,
                                                   Expression argument,
                                                   org.w3c.dom.Element currentNode,
                                                   String path)
    {
        List<String> attributeValues = SOAPUtils.getValuesFromElement(param.getName(), currentNode);

        if (attributeValues.isEmpty()) {
            if (param.getLower() == 0) {
                // ignoring optional attribute
                return;
            }
            else {
                if (currentNode != null) {
                    Console.traceln(Level.WARNING,
                                    "required attribute not found in SOAP message: " + path + "." +
                                        param.getName());
                    Console.traceln(Level.WARNING, "setting default values for this attribute");
                    Console.traceln(Level.FINE, "XML structure of path:" + StringTools.ENDLINE +
                        SOAPUtils.getSerialization(currentNode));
                }
                attributeValues.add(null);
            }
        }
        for (String attributeValue : attributeValues) {
            if ("String".equals(param.getType().getName())) {
                LiteralString spec =
                    (LiteralString) argument.createOperand(param.getName(), null,
                                                           UMLPackage.Literals.LITERAL_STRING);
                if (attributeValue != null) {
                    spec.setValue(attributeValue);
                }
                else {
                    spec.setValue("foobar");
                }
            }
            else if ("Integer".equals(param.getType().getName())) {
                LiteralInteger spec =
                    (LiteralInteger) argument.createOperand(param.getName(), null,
                                                            UMLPackage.Literals.LITERAL_INTEGER);
                if (attributeValue != null) {
                    spec.setValue(Integer.parseInt(attributeValue));
                }
                else {
                    spec.setValue(42);
                }
            }
            else if ("Boolean".equals(param.getType().getName())) {
                LiteralBoolean spec =
                    (LiteralBoolean) argument.createOperand(param.getName(), null,
                                                            UMLPackage.Literals.LITERAL_BOOLEAN);
                if (attributeValue != null) {
                    spec.setValue(Boolean.parseBoolean(attributeValue));
                }
                else {
                    spec.setValue(true);
                }
            }
            else if ("Real".equals(param.getType().getName())) {
                LiteralReal spec =
                    (LiteralReal) argument.createOperand(param.getName(), null,
                                                         UMLPackage.Literals.LITERAL_REAL);
                if (attributeValue != null) {
                    spec.setValue(Double.parseDouble(attributeValue));
                }
                else {
                    spec.setValue(3.14);
                }
            }
        }
    }

    /**
     * <p>
     * Creates a {@link Slot} in an {@link InstanceSpecification} for a primitive type.
     * </p>
     * 
     * @param instSpec
     *            instance specification to which the slot is added
     * @param prop
     *            property that describes the slot
     * @param currentNode
     *            DOM node from which is value for the slot is inferred
     * @param path
     *            used for warnings and debug information
     */
    private static void createSlotPrimitiveType(InstanceSpecification instSpec,
                                                Property prop,
                                                org.w3c.dom.Element currentNode,
                                                String path)
    {
        List<String> attributeValues = SOAPUtils.getValuesFromElement(prop.getName(), currentNode);

        if (attributeValues.isEmpty()) {
            if (prop.getLower() == 0) {
                // ignoring optional attribute
                return;
            }
            else {
                if (currentNode != null) {
                    Console.traceln(Level.WARNING,
                                    "required attribute not found in SOAP message: " + path + "." +
                                        prop.getName());
                    Console.traceln(Level.WARNING, "setting default values for this attribute");
                    Console.traceln(Level.FINE, "XML structure of path:" + StringTools.ENDLINE +
                        SOAPUtils.getSerialization(currentNode));
                }
                attributeValues.add(null);
            }
        }
        for (String attributeValue : attributeValues) {
            Slot slot = instSpec.createSlot();
            slot.setDefiningFeature(prop);
            if ("String".equals(prop.getType().getName())) {
                LiteralString value =
                    (LiteralString) slot.createValue(prop.getName(), null,
                                                     UMLPackage.Literals.LITERAL_STRING);
                if (attributeValue != null) {
                    value.setValue(attributeValue);
                }
                else {
                    value.setValue("foobar");
                }
            }
            else if ("Integer".equals(prop.getType().getName())) {
                LiteralInteger value =
                    (LiteralInteger) slot.createValue(prop.getName(), null,
                                                      UMLPackage.Literals.LITERAL_INTEGER);
                if (attributeValue != null) {
                    value.setValue(Integer.parseInt(attributeValue));
                }
                else {
                    value.setValue(42);
                }
            }
            else if ("Boolean".equals(prop.getType().getName())) {
                LiteralBoolean value =
                    (LiteralBoolean) slot.createValue(prop.getName(), null,
                                                      UMLPackage.Literals.LITERAL_BOOLEAN);
                if (attributeValue != null) {
                    value.setValue(Boolean.parseBoolean(attributeValue));
                }
                else {
                    value.setValue(true);
                }
            }
            else if ("Real".equals(prop.getType().getName())) {
                LiteralReal value =
                    (LiteralReal) slot.createValue(prop.getName(), null,
                                                   UMLPackage.Literals.LITERAL_REAL);
                if (attributeValue != null) {
                    value.setValue(Double.parseDouble(attributeValue));
                }
                else {
                    value.setValue(3.14);
                }
            }
            else {
                Console.traceln(Level.SEVERE, "could not create literal for primitive type: " +
                    prop.getType().getName());
                // TODO abort?
            }
        }
    }

    /**
     * <p>
     * Sets values for the parameters of a reply message. The values are, all LiterealNull and to
     * the INOUT, OUT and REPLY parameters, the UTP stereotype LiteralAny is applied.
     * </p>
     * 
     * @param replyMessage
     *            reply message for which the parameters are set
     * @param calledOperation
     *            operation that is replied for by the message
     */
    private static void setReplyMessageParameters(Message replyMessage, Operation calledOperation) {
        for (Parameter param : calledOperation.getOwnedParameters()) {
            Expression argument =
                (Expression) replyMessage.createArgument(param.getName(), param.getType(),
                                                         UMLPackage.Literals.EXPRESSION);
            if (isOutParameter(param)) {
                ValueSpecification operand =
                    argument.createOperand(null, param.getType(), UMLPackage.Literals.LITERAL_NULL);
                operand.applyStereotype(UTPUtils.getLiteralAnyStereotype(param.getModel()));
            }
            else {
                argument.createOperand(null, param.getType(), UMLPackage.Literals.LITERAL_NULL);
            }
        }
    }

    /**
     * <p>
     * Checks if a parameter has the direction IN or INOUT
     * </p>
     * 
     * @param parameter
     *            parameter that is checked
     * @return true if the direction is IN or INOUT; false otherwise
     */
    private static boolean isInParameter(Parameter parameter) {
        return parameter.getDirection() == ParameterDirectionKind.IN_LITERAL ||
            parameter.getDirection() == ParameterDirectionKind.INOUT_LITERAL;
    }

    /**
     * <p>
     * Checks if a parameter has the direction RETURN, OUT or INOUT
     * </p>
     * 
     * @param parameter
     *            parameter that is checked
     * @return true if the direction is RETURN, OUT, or INOUT; false otherwise
     */
    private static boolean isOutParameter(Parameter parameter) {
        return parameter.getDirection() == ParameterDirectionKind.RETURN_LITERAL ||
            parameter.getDirection() == ParameterDirectionKind.OUT_LITERAL ||
            parameter.getDirection() == ParameterDirectionKind.INOUT_LITERAL;
    }

    /**
     * <p>
     * Checks if the {@link MessageSort} of a message is a call message, i.e., ASYNCH_CALL or
     * SYNCH_CALL.
     * </p>
     * 
     * @param message
     *            message that is checked
     * @return true if the message is a call message; false otherwise
     */
    private static boolean isCallMessage(Message message) {
        if (message == null) {
            return false;
        }
        MessageSort msgSort = message.getMessageSort();
        return msgSort == MessageSort.ASYNCH_CALL_LITERAL ||
            msgSort == MessageSort.SYNCH_CALL_LITERAL;
    }

    /**
     * <p>
     * inverse-sorts the values of a map. Has been adapted from <a href=
     * "http://stackoverflow.com/questions/109383/how-to-sort-a-mapkey-value-on-the-values-in-java"
     * >this</a> StackOverflow post.
     * </p>
     * 
     * @param map
     *            map whose values are sorted
     * @return sorted version of the map
     */
    private static <K, V extends Comparable<? super V>> Map<K, V> sortByValue(Map<K, V> map) {
        // TODO possibly move to another class
        List<Map.Entry<K, V>> list = new LinkedList<>(map.entrySet());
        Collections.sort(list, new Comparator<Map.Entry<K, V>>() {
            @Override
            public int compare(Map.Entry<K, V> o1, Map.Entry<K, V> o2) {
                return -1 * (o1.getValue()).compareTo(o2.getValue());
            }
        });

        Map<K, V> result = new LinkedHashMap<>();
        for (Map.Entry<K, V> entry : list) {
            result.put(entry.getKey(), entry.getValue());
        }
        return result;
    }
}