source: trunk/src/org/expeditee/agents/DisplayTree.java@ 919

/**
 *    DisplayTree.java
 *    Copyright (C) 2010 New Zealand Digital Library, http://expeditee.org
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation, either version 3 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.expeditee.agents;

import org.expeditee.gui.DisplayIO;
import org.expeditee.gui.Frame;
import org.expeditee.gui.MessageBay;
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 {

        public static final int GARBAGE_COLLECTION_THRESHOLD = 100000;

        private Runtime _runtime = Runtime.getRuntime();
        
        public DisplayTree(String delay) {
                super(delay);
        }

        public DisplayTree() {
                super();
        }

        @Override
        public boolean initialise(Frame start, Item launcher) {

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

                return super.initialise(start, launcher);
        }

        @Override
        protected void finalise(Frame start) {
                // return the user to the Frame they started on
                if (!_stop) {
                        DisplayIO.Back();
                }
                super.finalise(start);
        }

        @Override
        protected void processFrame(Frame toProcess) {
                long freeMemory = _runtime.freeMemory();
                if (freeMemory < GARBAGE_COLLECTION_THRESHOLD) {
                        _runtime.gc();
                        MessageBay.displayMessage("Force Garbage Collection!");
                }

                // FrameUtils.ResponseTimer.restart();

                // ignore loops
                if (toProcess != DisplayIO.getCurrentFrame())
                        DisplayIO.setCurrentFrame(toProcess, false);
                // 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);
        }
}