This is a mobile version, full one is here.
Yegor Bugayenko
15 August 2014
How to Retry Java Method Call on Exception
If you have a method that fails occasionally and
you want to retry it a few times before
throwing
an exception. @RetryOnFailure
from
jcabi-aspects can help.
For example, if you're downloading the following web page:
@RetryOnFailure( attempts = 3, delay = 10, unit = TimeUnit.SECONDS ) public String load(URL url) { return url.openConnection().getContent(); }
This method call will throw an exception only after three failed executions with a ten seconds interval between them.
This post explains how jcabi-aspects works with binary weaving. This mechanism integrates AspectJ with your code.
When method load()
from the example above is called, this is what
is happening behind the scene (pseudo-code):
while (attempts++ < 3) { try { return original_load(url); } catch (Throwable ex) { log("we failed, will try again in 10 seconds"); sleep(10); } }
This approach may be very useful in the following situations (based on my experience):
Executing JDBC
SELECT
statementsLoading data from HTTP, S3, FTP, etc resources
Uploading data over the network
Fetching data through RESTful stateless API-s
The project is in GitHub.