source: trunk/src/org/expeditee/items/JSThreadable.java@ 1450

/**
 *    JSThreadable.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.items;

import javax.script.ScriptEngine;

public interface JSThreadable {
        public static final class JSThread {
                private Thread thread;
                private final String code;
                private final ScriptEngine scriptEngine;
                private boolean run = false;
                
                public JSThread(ScriptEngine scriptEngine, String code) {
                        this.code = code;
                        this.thread = null;
                        this.scriptEngine = scriptEngine;
                }
                
                /**
                 * Stops the thread,
                 * but leaves it's state so it will run next time
                 */
                public void kill() {
                        if(thread != null) {
                                thread.interrupt();
                                try {
                        thread.join();
                } catch (InterruptedException e) {
                        e.printStackTrace();
                }
                                thread = null;
                        }
                }
                
                /**
                 * Starts the thread if it isn't running and should be running
                 */
                public void resume() {
                        if(!this.run)
                                return;
                        if(thread != null)
                                return;
                        thread = new Thread(new Runnable() {
                        @Override
                        public void run() {
                                try {
                        scriptEngine.eval("thread = " + code + "\nthread()");
                        run = false;
                                } catch (Exception e) {
                                        if(e instanceof InterruptedException || e.getCause() instanceof InterruptedException) {
                                                // if the thread was interrupted exit quietly
                                                return;
                                        }
                                        e.printStackTrace();
                    }
                        }
                });
                        thread.start();
                }
                
                public boolean shouldRun() {
                        return this.run;
                }
                
                public void shouldRun(boolean run) {
                        this.run = run;
                }
                
                public void stop() {
                        this.kill();
                        this.run = false;
                }
                
                public void start() {
                        this.kill();
                        this.run = true;
                        this.resume();
                }
        }
        
        public JSThread addThread(String code);
}