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<p>
A mechanism for selectively retrying methods that throw exceptions under certain circumstances.
</p>

<p>
Typical usage is
</p>

<pre>
UnreliableImplementation unreliableImpl = new UnreliableImplementation();
UnreliableInterface unreliable = (UnreliableInterface)
  RetryProxy.create(UnreliableInterface.class, unreliableImpl,
    RetryPolicies.retryUpToMaximumCountWithFixedSleep(4, 10, TimeUnit.SECONDS));
unreliable.call();
</pre>

<p>
This will retry any method called on <code>unreliable</code> four times - in this case the <code>call()</code>
method - sleeping 10 seconds between
each retry. There are a number of {@link org.apache.hadoop.io.retry.RetryPolicies retry policies}
available, or you can implement a custom one by implementing {@link org.apache.hadoop.io.retry.RetryPolicy}.
It is also possible to specify retry policies on a 
{@link org.apache.hadoop.io.retry.RetryProxy#create(Class, Object, Map) per-method basis}.
</p>

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