[jbossts-issues] [JBoss JIRA] (JBTM-971) Allow a ServiceRequst method to programaticaly state that it is ReadOnly

[Paul Robinson (Updated) (JIRA)]

     [ https://issues.jboss.org/browse/JBTM-971?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Paul Robinson updated JBTM-971:
-------------------------------

    Description: 
This method can be called from a web service method while a transaction is active to notify the framework that no changes have been made during execution of the service method. This is a useful alternative to annotating the ServiceRequest as ReadOnly as it allows the business logic to decide at runtime if modifications were made.

{code}
public interface Control
{
    public void readOnly();
}
{code}



  was:
The RequestType attribute on the ServiceRequest annotation identifies whether the service request is always read only as far as transactional modifications are concerned or, alternatively, that it may make changes to transactional data. in the latter case the service request method can indicate a read-only outcome by invoking the readOnly method of an injected control.

{code}
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface ServiceRequest
{
    public RequestType requestType() default RequestType.MODIFY;
}
{code}

The framework does not normally register lifecycle callbacks for ServiceRequest methods whose request type is READ_ONLY (see the next paragraph for the rider which qualifies this statement). The framework does normally register callbacks for ServiceRequest methods whose request type is  MODIFY, on the assumption that the method has performed transactional changes. The latter methods may inhibit registration of lifecycle methods by calling the readOnly() method of an injected transaction control.

The reason why it is important to identify READ_ONLY methods is that they affect the way the framework performs PREPARE or COMPLETE processing (as appropriate to the protocol in question). If all ServiceRequest methods in the transaction are READ_ONLY the participant will trigger READ_ONLY or EXIT callbacks, respectively, for these lifecycle events, precluding further involvement in the transaction. If any of the ServiceRequest methods is not READ_ONLY then the framework will trigger PREPARE or COMPLETE callbacks, respectively. Clearly, it would be futile for a READ_ONLY declaration or notification to inhibit registration of callbacks which are triggered by READ_ONLY or EXIT events. So, the framework only registers READ_ONLY or EXIT lifecycle callbacks when they are triggered by READ_ONLY methods or by MODIFY methods which notify their READ_ONLY status using an injected control.


    
> Allow a ServiceRequst method to programaticaly state that it is ReadOnly
> ------------------------------------------------------------------------
>
>                 Key: JBTM-971
>                 URL: https://issues.jboss.org/browse/JBTM-971
>             Project: JBoss Transaction Manager
>          Issue Type: Feature Request
>      Security Level: Public(Everyone can see) 
>          Components: TxBridge
>            Reporter: Paul Robinson
>            Assignee: Paul Robinson
>             Fix For: 5.0.0.M2
>
>
> This method can be called from a web service method while a transaction is active to notify the framework that no changes have been made during execution of the service method. This is a useful alternative to annotating the ServiceRequest as ReadOnly as it allows the business logic to decide at runtime if modifications were made.
> {code}
> public interface Control
> {
>     public void readOnly();
> }
> {code}

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