com.sas.iquery.util
Class RetryUtil

com.sas.iquery.util.RetryUtil

public class RetryUtil

Utility class to simplify adding a try-retry behavior for methods.

Example:

 RetryUtil.Actor actor = new RetryUtil.Actor() {
     AssociationList list = acList;









Nested Class Summary




static class
RetryUtil.ActionFailed



          Exception thrown by the RetryUtil.tryAction() method when the action fails and 
 cannot be retried or all retries fail.



static interface
RetryUtil.Actor<V>



           



static class
RetryUtil.FailAction



          Exception thrown by the RetryUtil.tryAction() method when the action fails and no retry should be done.



static class
RetryUtil.RedoAction



          Exception thrown by the Actor.action() method when a retry should be done.


 


Field Summary




static java.lang.String
IQ_RETRYUTIL_LOGGING



          Logging context to enable monitoring of RetryUtil retry behavior.



static java.lang.Integer
IQ_RETRYUTIL_MAX_RETRIES_DEFAULT



          Default value for IQ.RetryUtil.MaxRetries if not specified is 10 retries.



static java.lang.String
IQ_RETRYUTIL_MAX_RETRIES_PROPNAME



          System property to control the number of retries when attempting to retrieve members from an
 AssociationList that is being modified.



static java.lang.Integer
IQ_RETRYUTIL_WAIT_MS_DEFAULT



          Default value for IQ.RetryUtil.RetryWaitMs is 10 milliseconds wait between attempts.



static java.lang.String
IQ_RETRYUTIL_WAIT_MS_PROPNAME



          System property to control the number of milliseconds to wait between attempts to retrieve members 
 from an AssociationList that is being modified.


 



Constructor Summary
RetryUtil()



           
 



Method Summary




static

<T> T

tryAction(RetryUtil.Actor<T> actor)



          Performs the action() of the Actor object and returns the value from that method
 for either 10 attempts or for the value of the system property "IQ.RetryUtil.MaxRetries".



static

<T> T

tryAction(RetryUtil.Actor<T> actor,
          org.apache.log4j.Logger logger)



          Performs the action() of the Actor object and returns the value from that method
 for either 10 attempts or for the value of the system property "IQ.RetryUtil.MaxRetries".



static

<T> T

tryAction(RetryUtil.Actor<T> actor,
          long maxRetries,
          long retryWaitMs,
          org.apache.log4j.Logger logger)



          Performs the action() of the Actor object and returns the value from that method.


 





Field Detail



IQ_RETRYUTIL_WAIT_MS_PROPNAME
public static final java.lang.String IQ_RETRYUTIL_WAIT_MS_PROPNAME

System property to control the number of milliseconds to wait between attempts to retrieve members 
 from an AssociationList that is being modified.  A value of 0 or greater will cause the retrieving
 thread to execute a Thread.sleep(milliseconds) between attempts and any interrupts
 recieved during that sleep will cause the most recent retry failure to be thrown.


See Also:
Constant Field Values




IQ_RETRYUTIL_WAIT_MS_DEFAULT
public static final java.lang.Integer IQ_RETRYUTIL_WAIT_MS_DEFAULT

Default value for IQ.RetryUtil.RetryWaitMs is 10 milliseconds wait between attempts.







IQ_RETRYUTIL_MAX_RETRIES_PROPNAME
public static final java.lang.String IQ_RETRYUTIL_MAX_RETRIES_PROPNAME

System property to control the number of retries when attempting to retrieve members from an
 AssociationList that is being modified.  A value less than 1 will not retry and will throw
 the first java.util.ConcurrentModificationException encountered (if any).


See Also:
Constant Field Values




IQ_RETRYUTIL_MAX_RETRIES_DEFAULT
public static final java.lang.Integer IQ_RETRYUTIL_MAX_RETRIES_DEFAULT

Default value for IQ.RetryUtil.MaxRetries if not specified is 10 retries.







IQ_RETRYUTIL_LOGGING
public static final java.lang.String IQ_RETRYUTIL_LOGGING

Logging context to enable monitoring of RetryUtil retry behavior.


See Also:
Constant Field Values





Constructor Detail



RetryUtil
public RetryUtil()






Method Detail



tryAction
public static <T> T tryAction(RetryUtil.Actor<T> actor,
                              org.apache.log4j.Logger logger)
                   throws RetryUtil.ActionFailed

Performs the action() of the Actor object and returns the value from that method
 for either 10 attempts or for the value of the system property "IQ.RetryUtil.MaxRetries".
 If that property is set to less than 1, then no retries will be made.


Parameters:
actor - 
logger - logger to use for log messages, if null then no logging will be done.
Returns:
result from the Actor.action() call.
Throws:
RetryUtil.ActionFailed - if the action and retries fail, its getCause() should return any exception responsible.





tryAction
public static <T> T tryAction(RetryUtil.Actor<T> actor)
                   throws RetryUtil.ActionFailed

Performs the action() of the Actor object and returns the value from that method
 for either 10 attempts or for the value of the system property "IQ.RetryUtil.MaxRetries".
 If that property is set to less than 1, then no retries will be made.
 By default, this method writes log messages to the IQ.RetryUtil.Logging context.


Parameters:
actor - 
Returns:
result from the Actor.action() call.
Throws:
RetryUtil.ActionFailed - if the action and retries fail, its getCause() should return any exception responsible.





tryAction
public static <T> T tryAction(RetryUtil.Actor<T> actor,
                              long maxRetries,
                              long retryWaitMs,
                              org.apache.log4j.Logger logger)
                   throws RetryUtil.ActionFailed

Performs the action() of the Actor object and returns the value from that method.
 If the retry value is set to less than 1, then no retries will be made.


Parameters:
actor - 
maxRetries - maximum number of retries after the first attempt (<1 means no retries).
retryWaitMs - maximum time to wait between attempts in milliseconds (<0 means do not pause the thread).
logger - null if no logger messages should be output.
Returns:
result from the Actor.action() call.
Throws:
RetryUtil.ActionFailed - if the action and retries fail, its getCause() should return any exception responsible.