/// <summary>
/// Creates a new instance of the <see cref="Controller"/> class.
/// </summary>
public Controller()
{
globals = Globals.Instance();
log = new QueueEventLogger(100);
crawler = null;
stats = new long[10];
proxy = CrawlWaveServerProxy.Instance(globals);
}
/// <summary>
/// Attempts to stop the Crawler.
/// </summary>
/// <returns>Null if the operation succeeds, or a <see cref="SerializedException"/>
/// encapsulating the error that occured if the operation fails.</returns>
/// <exception cref="InvalidOperationException">Thrown if the Crawler has not yet been initialized.</exception>
public SerializedException Stop()
{
SerializedException sx = null;
try
{
if(Crawler.InstanceExists())
{
if(crawler == null)
{
crawler = Crawler.Instance();
AttachObservers();
}
crawler.StopImmediately();
}
else
{
throw new InvalidOperationException("The Crawler has not been initialized and cannot be stopped.");
}
}
catch(Exception e)
{
sx = new SerializedException(e.GetType().ToString(), e.Message, e.StackTrace);
}
return sx;
}
/// <summary>
/// Retrieves the crawler's statistics as an array of longs.
/// </summary>
/// <returns>An array of longs containing the crawler's statistics.</returns>
public long[] GetStatistics()
{
if(Crawler.InstanceExists())
{
if(crawler == null)
{
crawler = Crawler.Instance();
AttachObservers();
}
for(int i = 0; i<10; i++)
{
stats[i] = crawler.Statistics[i];
}
}
return stats;
}
/// <summary>
/// Attempts to start the Crawler and enable the logging of events.
/// </summary>
/// <returns>Null if the operation succeeds, or a <see cref="SerializedException"/>
/// encapsulating the error that occured if the operation fails.</returns>
public SerializedException Start()
{
SerializedException sx = null;
try
{
if(crawler == null)
{
crawler = Crawler.Instance();
AttachObservers();
}
crawler.Start();
}
catch(Exception e)
{
sx = new SerializedException(e.GetType().ToString(), e.Message, e.StackTrace);
}
return sx;
}
/// <summary>
/// Provides a global access point for the single instance of the <see cref="Crawler"/>
/// class.
/// </summary>
/// <returns>A reference to the single instance of <see cref="Crawler"/>.</returns>
public static Crawler Instance()
{
if (instance==null)
{
//Make sure the call is thread-safe.
Mutex mutex=new Mutex();
mutex.WaitOne();
if( instance == null )
{
instance = new Crawler();
}
mutex.Close();
}
return instance;
}
