Android Open Source - MassRoute Service Task Queue

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Back to project page MassRoute.

License

The source code is released under:

Copyright (c) 2010 Todd Anderson http://www.custardbelly.com/blog Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (th...

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Java Source Code

package com.custardbelly.massdot.service;
/* www  .jav a  2  s  .  com*/
import java.net.URL;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import android.content.Context;
import android.os.AsyncTask;
import android.os.Handler;
import android.widget.Toast;

import com.custardbelly.massdot.R;

public class ServiceTaskQueue implements IServiceTaskQueue, IQueueableTaskResponder
{  
  // Must wait at least 10 seconds between service calls as explained in MassDOT documentation.
  final long minimumElapse = 10000;
  
  long _lastTaskTime;
  boolean _isRunning;
  List<TaskToken> _tasks;
  Handler _taskHandler;
  
  private Context _context;
  
  public ServiceTaskQueue( Context context )
  {
    _context = context;
    
    _isRunning = false;
    _tasks = new ArrayList<TaskToken>();
    _taskHandler = new Handler();
    _lastTaskTime = 0;
  }
  
  protected void runNextTask()
  {
    _isRunning = ( _tasks.size() > 0 );
    if( _isRunning )
    {
      // check timer.
      final long currentTime = new Date().getTime();
      final long elapse = ( _lastTaskTime == 0 ) ? currentTime : ( currentTime - _lastTaskTime );
      if( elapse < minimumElapse )
      {
        String alert = _context.getString( R.string.delayed_request_alert );
        float seconds = ( ( elapse ) - 1000 ) / 1000;
        Toast.makeText( _context, alert.replace( "{0}", Float.toString( seconds ) ), Toast.LENGTH_LONG);
        // start timer with elapse
        Runnable t = new Runnable() {
          public void run()
          {
            runNextTask();
          }
        };
        _taskHandler.postAtTime( t, elapse );
      }
      else
      {
        // reset time, execute task.
        _lastTaskTime = new Date().getTime();
        TaskToken token = _tasks.remove(0);
        AsyncTask<URL, Integer, Long> task = token.task;
        task.execute( token.url );
      }
    }
  }

  public void handleQueueableTaskResult()
  {
    runNextTask();
  }
  public void handleQueueableTaskFault()
  {
    runNextTask();
  }
  
  public void push( AsyncTask<URL, Integer, Long> task, URL url, boolean autostart ) 
  {
    _tasks.add( new TaskToken( task, url ) );
    
    if( autostart && !_isRunning )
      flush();
  }
  
  public void flush() 
  {
    runNextTask();
  }
  
  public void empty()
  {
    while( _tasks.size() > 0 )
      _tasks.remove(0);
    
    _tasks = new ArrayList<TaskToken>();
  }
  
  private class TaskToken
  {
    AsyncTask<URL, Integer, Long> task;
    URL url;
    public TaskToken( AsyncTask<URL, Integer, Long> task, URL url )
    {
      this.task = task;
      this.url = url;
    }
  }
}

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