source: trunk/EventBenchConsole/src/de/ugoe/cs/eventbench/windows/SequenceSplitter.java

package de.ugoe.cs.eventbench.windows;

import java.util.LinkedList;
import java.util.List;

import de.ugoe.cs.eventbench.data.Event;
import de.ugoe.cs.eventbench.windows.data.WindowsEvent;
import de.ugoe.cs.eventbench.windows.data.WindowsMessage;
import de.ugoe.cs.util.console.Console;

/**
 * <p>
 * Responsible to split sequences into subsequences, such that each subsequences
 * contains exactly one event.
 * </p>
 * 
 * @author Steffen Herbold
 * @version 1.0
 */
public class SequenceSplitter {

        /**
         * <p>
         * Contains the current subsequence.
         * </p>
         */
        private List<WindowsMessage> currentSequence;

        /**
         * <p>
         * Number of messages in the current sequences, that signal that a key or
         * mouse button has been pressed down to which not yet a message has been
         * found, that signals that the button has been released.
         * </p>
         */
        private int openDowns;

        /**
         * <p>
         * Internal flag that signals if {@link #currentSequence} needs to be
         * initialized.
         * </p>
         */
        private boolean initMessages;

        /**
         * <p>
         * The {@link EventGenerator} used to convert the subsequences into
         * {@link Event}s
         * </p>
         */
        private EventGenerator tokenGenerator;

        /**
         * <p>
         * The event sequence generated.
         * </p>
         */
        private List<WindowsEvent> actionSequence;

        /**
         * <p>
         * Type of the previous message.
         * </p>
         */
        private int prevMsg = 0;

        /**
         * <p>
         * Constructor. Creates a new SequenceSplitter.
         * </p>
         */
        public SequenceSplitter() {
                currentSequence = new LinkedList<WindowsMessage>();
                openDowns = 0;
                initMessages = true;
                tokenGenerator = new EventGenerator();
                actionSequence = new LinkedList<WindowsEvent>();
                prevMsg = 0;
        }

        /**
         * <p>
         * Called by the {@link MFCLogParser} every time a message is parsed.
         * </p>
         * 
         * @param msg
         *            message to be added
         */
        public void addMessage(WindowsMessage msg) {
                if (startOfSequence(msg)) {
                        if (!initMessages) {
                                WindowsEvent currentAction = tokenGenerator
                                                .generateEvent(currentSequence);
                                if (currentAction != null) {
                                        actionSequence.add(currentAction);
                                }
                                if (isKeyMessage(msg.getType()) && openDowns > 0) {
                                        Console.traceln("Key message found with open down mouse messages - will probabably result in a faulty sequence.");
                                }
                        } else {
                                initMessages = false;
                        }
                        currentSequence = new LinkedList<WindowsMessage>();
                }
                if (isUpMessage(msg.getType())) {
                        if (openDowns > 0) {
                                openDowns--;
                        }
                }

                // this fix checks if there are two consecutive mouse-down messages.
                // This sometimes occurs due to incorrect filtering in the monitoring
                // dll.
                if (!(prevMsg == MessageDefs.WM_LBUTTONDOWN && prevMsg == msg.getType())) {
                        currentSequence.add(msg);
                } else {
                        openDowns--;
                }
                prevMsg = msg.getType();
        }

        /**
         * <p>
         * Returns the event sequence generated from the message that have been
         * added.
         * </p>
         * 
         * @return generated event sequence
         */
        public List<WindowsEvent> getSequence() {
                return actionSequence;
        }

        /**
         * <p>
         * Called when a session in the log file is finished, i.e., a closing
         * session-node is found.
         * </p>
         */
        public void endSession() {
                WindowsEvent currentAction = tokenGenerator
                                .generateEvent(currentSequence);
                if (currentAction != null) {
                        actionSequence.add(currentAction);
                }
        }

        /**
         * <p>
         * Checks if the message starts a new subsequence and returns the result.
         * </p>
         * 
         * @param msg
         *            message that is checked
         * @return true, if a new subsequence begins
         */
        private boolean startOfSequence(WindowsMessage msg) {
                boolean isStart = false;
                int msgType = msg.getType();
                if (isKeyMessage(msgType)) {
                        isStart = true;
                }
                if (isDownMessage(msgType)) {
                        openDowns++;
                        if (openDowns == 1) {
                                isStart = true;
                        }
                }
                if (isDblclkMessage(msgType)) {
                        openDowns++;
                }
                return isStart;
        }

        /**
         * <p>
         * Checks if the type of a message is generated is a keyboard interaction.
         * </p>
         * 
         * @param msgType
         *            type of the message
         * @return true if it is a keyboard interaction; false otherwise
         */
        private boolean isKeyMessage(int msgType) {
                boolean isKeyMsg = false;
                switch (msgType) {
                case MessageDefs.WM_KEYDOWN:
                case MessageDefs.WM_KEYUP:
                case MessageDefs.WM_SYSKEYDOWN:
                case MessageDefs.WM_SYSKEYUP:
                        isKeyMsg = true;
                        break;
                default:
                        break;
                }
                return isKeyMsg;
        }

        /**
         * <p>
         * Checks if the type of a message indicates that the mouse has been pressed
         * down.
         * </p>
         * 
         * @param msgType
         *            type of the message
         * @return true if it is mouse-down message; false otherwise
         */
        private boolean isDownMessage(int msgType) {
                boolean isDownMsg = false;
                switch (msgType) {
                case MessageDefs.WM_LBUTTONDOWN:
                case MessageDefs.WM_RBUTTONDOWN:
                case MessageDefs.WM_MBUTTONDOWN:
                case MessageDefs.WM_XBUTTONDOWN:
                case MessageDefs.WM_NCLBUTTONDOWN:
                case MessageDefs.WM_NCRBUTTONDOWN:
                case MessageDefs.WM_NCMBUTTONDOWN:
                case MessageDefs.WM_NCXBUTTONDOWN:
                        isDownMsg = true;
                        break;
                default:
                        break;
                }
                return isDownMsg;
        }

        /**
         * <p>
         * Checks if the type of a message indicates that a double click has been
         * performed.
         * </p>
         * 
         * @param msgType
         *            type of the message
         * @return true if it is a double click message; false otherwise
         */
        private boolean isDblclkMessage(int msgType) {
                boolean isDblclkMsg = false;
                switch (msgType) {
                case MessageDefs.WM_LBUTTONDBLCLK:
                case MessageDefs.WM_RBUTTONDBLCLK:
                case MessageDefs.WM_MBUTTONDBLCLK:
                case MessageDefs.WM_XBUTTONDBLCLK:
                case MessageDefs.WM_NCLBUTTONDBLCLK:
                case MessageDefs.WM_NCRBUTTONDBLCLK:
                case MessageDefs.WM_NCMBUTTONDBLCLK:
                case MessageDefs.WM_NCXBUTTONDBLCLK:
                        isDblclkMsg = true;
                        break;
                default:
                        break;
                }
                return isDblclkMsg;
        }

        /**
         * <p>
         * Checks if the type of a message indicates that the mouse has been
         * released.
         * </p>
         * 
         * @param msgType
         *            type of the message
         * @return true if it is mouse-up message; false otherwise
         */
        private boolean isUpMessage(int msgType) {
                boolean isUpMsg = false;
                switch (msgType) {
                case MessageDefs.WM_LBUTTONUP:
                case MessageDefs.WM_RBUTTONUP:
                case MessageDefs.WM_MBUTTONUP:
                case MessageDefs.WM_XBUTTONUP:
                case MessageDefs.WM_NCLBUTTONUP:
                case MessageDefs.WM_NCRBUTTONUP:
                case MessageDefs.WM_NCMBUTTONUP:
                case MessageDefs.WM_NCXBUTTONUP:
                        isUpMsg = true;
                        break;
                default:
                        break;
                }
                return isUpMsg;
        }

}