source: trunk/org/expeditee/agents/DisplayTree.java@ 4

package org.expeditee.agents;

import org.expeditee.gui.DisplayIO;
import org.expeditee.gui.Frame;
import org.expeditee.gui.FrameUtils;
import org.expeditee.gui.TimeKeeper;
import org.expeditee.items.Item;
import org.expeditee.items.ItemUtils;
import org.expeditee.items.Text;

/**
 * Displays the Tree of Frames starting from the given frame. The delay between
 * frames can be adjusted, either per-frame with the
 * 
 * @DisplayFramePause tag, or mid-stream with the
 * @DisplayTreePause tag, both tags should be followed with the desired delay in
 *                   ms. The default delay between Frames is 50ms.
 * @author jdm18
 * 
 */
public class DisplayTree extends TreeProcessor {

        // delay between frames, in ms
        private long _delay = 50;

        // The shortest delay between frames
        private static final long TIMER_RESOLUTION = 10;

        private long _timeRemaining = 0;

        private int _frameCount = 0;

        private TimeKeeper _timer;

        public DisplayTree(String delay) {
                super();
                try {
                        _delay = Long.parseLong(delay);
                } catch (Exception e) {
                }
        }

        public DisplayTree() {
                super();
        }

        @Override
        public boolean initialise(Frame start) {
                _timer = new TimeKeeper();

                // push current frame on to back-stack
                DisplayIO.addToBack(start);

                // MIKE: Doesnt think the line below is needed
                // update the delays (if necessary)
                // delay(start);

                return true;
        }

        @Override
        protected void processFrame(Frame toProcess) {
                // ignore loops
                if (toProcess != DisplayIO.getCurrentFrame())
                        FrameUtils.DisplayFrame(toProcess, false);

                FrameUtils.ResponseTimer.restart();

                // parse the frame for any pause settings
                delay(toProcess);

                _frameCount++;
        }

        /**
         * Parses through the given Frame to find any
         * 
         * @DisplayTreePause or
         * @DisplayFramePause tags, and updates the delay or pause as necessary
         * @param toSearch
         */
        private void delay(Frame toSearch) {
                // check for change in globaly delay time
                Item delay = ItemUtils.FindTag(toSearch.getItems(),
                                "@DisplayTreePause:");
                if (delay != null) {
                        try {
                                // attempt to read in the delay value
                                _delay = Long.parseLong(ItemUtils.StripTag(((Text) delay)
                                                .getFirstLine(), "@DisplayTreePause:"));
                                message("DisplayTree delay changed to: " + _delay + "ms");
                        } catch (NumberFormatException nfe) {
                                message("Incorrect paramter for DisplayTreePause");
                        }

                }

                // check for change in delay for this frame only
                delay = ItemUtils.FindTag(toSearch.getItems(), "@DisplayFramePause:");
                if (delay != null) {
                        try {
                                // attempt to read in the delay value
                                long pause = Long.parseLong(ItemUtils.StripTag(((Text) delay)
                                                .getFirstLine(), "@DisplayFramePause:"));
                                pause(pause);
                        } catch (NumberFormatException nfe) {
                                message("Incorrect paramter for DisplayFramePause");
                        }
                } else
                        pause(_delay);
        }

        @Override
        protected void finalise(Frame start) {
                if (_frameCount == 0)
                        _frameCount++;
                
                long avg = _timer.getElapsedMillis() / _frameCount;
                String stats = "Frames: " + _frameCount + ", Time: "
                                + _timer.getElapsedStringMillis() + ", Average: " + avg;
                String msg = "Tree successfully displayed. ";

                // return the user to the Frame they started on
                if (!_stop) {
                        DisplayIO.Back();
                } else {
                        msg = "Agent halted by user. ";
                }

                message(msg + stats);
        }

        /**
         * Pauses the execution of this Agent for the given time period (in ms.)
         * This is used for the delay between displaying frames.
         * 
         * @param time
         */
        private void pause(long time) {
                try {
                        if (time < 0)
                                _timeRemaining = Long.MAX_VALUE;
                        else
                                _timeRemaining = time;

                        while (_timeRemaining > 0) {
                                Thread.yield();
                                Thread.sleep(TIMER_RESOLUTION);
                                _timeRemaining -= TIMER_RESOLUTION;
                        }
                } catch (InterruptedException e) {
                }
        }

        @Override
        public void interrupt() {
                _timeRemaining = 0;
        }

        @Override
        public void stop() {
                _timeRemaining = 0;
                super.stop();
        }

}