/*
   TextFromWebServiceApp.java by Kari Laitinen

   http://www.naturalprogramming.com/

   2015-01-02 File created.

   Thir program demonstrates how to use Java FX classes to read
   a text file that is located on a server on the Internet.

*/

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.concurrent.Service;
import javafx.concurrent.Task;
import javafx.concurrent.WorkerStateEvent;
import javafx.event.EventHandler;
import javafx.stage.Stage;

public class TextFromWebServiceApp extends Application
{

    @Override
    public void start( Stage stage ) throws Exception
    {
        TextFromWebService text_service = new TextFromWebService() ;

        text_service.setUrl(
        "http://www.naturalprogramming.com/javabookprograms/javafilesextra/testfile.txt");


        // Next, we specify what will be done after the Task, that is 
        // specified inside the TextFromWebService class, is completed
        // successfully.

        text_service.setOnSucceeded( ( WorkerStateEvent event ) ->
        {
            System.out.println( event.getSource().getValue() ) ;
            
        } ) ;

        text_service.start() ;
    }

    public static void main( String[] not_in_use )
    {
       launch() ;
    }

    private static class TextFromWebService extends Service<String>
    {
        private StringProperty text_file_url = new SimpleStringProperty() ;

        public final void setUrl( String url_as_string )
        {
            text_file_url.set( url_as_string ) ;
        }

        public final String getUrl()
        {
            return text_file_url.get() ;
        }

        public final StringProperty urlProperty()
        {
           return text_file_url ;
        }


        @Override
        protected Task<String> createTask()
        {
            return new Task<String>()
            {
                @Override
                protected String call()
                        throws IOException, MalformedURLException
                {
                    URL text_url = new URL( getUrl() ) ;

                    BufferedReader  buffered_reader = new BufferedReader(
                              new InputStreamReader( text_url.openStream() ) ) ;

                    StringBuilder all_text_lines = new StringBuilder() ;

                    String text_line_from_web ;

                    while ( ( text_line_from_web = buffered_reader.readLine() )
                                                            != null )
                    {
                        all_text_lines.append( text_line_from_web + "\n" ) ;
                    }

                    buffered_reader.close() ;
                        
                    return all_text_lines.toString() ;
                    
                }
            } ;
        }
    }
}


/* NOTES:

The following pages might be useful to read:

http://docs.oracle.com/javase/8/javafx/interoperability-tutorial/concurrency.htm

https://docs.oracle.com/javase/8/javafx/api/javafx/concurrent/Service.html

http://docs.oracle.com/javase/8/javafx/api/javafx/concurrent/Task.html


//  The following is another possible way to handle the OnSucceeded event:

        text_service.setOnSucceeded( new EventHandler<WorkerStateEvent>()
        {

            @Override
            public void handle(WorkerStateEvent t) {
                System.out.println( t.getSource().getValue());
            }
        } ) ;


*/