org.dice_research.squirrel.fetcher.delay

Interface Delayer

All Known Implementing Classes:

DummyDelayer, StaticDelayer

public interface Delayer

A delayer can be used to make sure that a server is flooded with requests, i.e., a fetcher is aware of doing delays between single requests without programming the delay functionality in all fetcher instances.

The submission of the request and receiving the response should be encapsulated by the two method calls of the Delayer instance

 Delayer d;
 d.getRequestPermission();
 try {
     // perform request
 } finally {
     d.requestFinished();
 }
 

Author:

Michael Röder (michael.roeder@uni-paderborn.de)

Method Summary

Modifier and Type	Method and Description
long	getDelay() Returns the delay (in ms) that this instance typically would introduce between two consecutive requests.
void	getRequestPermission() Waits for the permission to perform a new request.
void	requestFinished() informs the Delayer instance about the finished request.

Method Detail

getRequestPermission

void getRequestPermission()
                   throws InterruptedException

Waits for the permission to perform a new request.

Throws:

InterruptedException - if the internal waiting is interrupted.

requestFinished

void requestFinished()

informs the Delayer instance about the finished request. Note that missing to call this method might lead to a deadlock.

getDelay

long getDelay()

Returns the delay (in ms) that this instance typically would introduce between two consecutive requests.

Returns:

the delay (in ms) that this instance typically would introduce between two consecutive requests