TopLink Essentials enhancements - category-specific logging level and cascade refresh query hint

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Wonseok Kim

TopLink Essentials 2.0 and maven repository | Main | EclipseLink sessions in 2008 JavaOne

TopLink Essentials enhancements - category-specific logging level and cascade refresh query hint

Posted by guruwons on July 6, 2007 at 7:39 PM PDT

Recently I've implemented two minor but useful features for TopLink Essentials(TLE) v2 b54(or GlassFish v2 b54). One is the category-specific logging level configuration[1] which is useful for who want to see only SQL logs and the other is the cascade refresh query hint[2] which control the cascade scope of the refresh query dynamically.

Let's see what these are...

Category-specific logging level

Configuring logging level for a PU(Persistence Unit) could be done by "toplink.logging.level" property like below.

     <persistence-unit name="pu1">
         ...
        <properties> 
            ...
            <property name="toplink.logging.level" value="FINE"/> 
         </properties> 
     </persistence-unit>


 
 To see SQLs triggerred by TLE the logging level should be FINE. However this will print other many FINE logs which may be of little interest to normal users. This is like all-or-nothing choice.
 
 Fortunately the logging platform of TLE basically supports categories for different types of logs - "sql", "connection", "transaction" and so on.
 This enable users to watch interested logs of specific categories. Especially the "sql" category is the most interesting one.
 
 However there had been no easy way to configure the logging level for the specific category. So I've added the following new category logging level property and connected it with logger code.
 
                              Property
                       Description
            
                     toplink.loging.level.<category>              Control the log level for a specific category.

Categories(defined in oracle.toplink.essentials.logging.SessionLog):
                                 sql - SQL logs
           
                        transaction - Transaction related logs
           
                        event           
                        connection - Session related logs
           
                        query - DatabaseQuery related logs
           
                        cache - shared cache logs
           
                        propagation           
                        sequencing - sequencing generator logs
           
                        ejb           
                        dms           
                        ejb_or_metadata - metadata processing logs
           
                        weaver - class weaver logs
           
                        properties - deployment time properties handler logs
           
         
         
         Valid values are defined in java.util.logging.Level
         
         If there is no category-specific level, the level set with toplink.logging.level(INFO is default) is used.
         
Example: to see SQL logs
         <property name="toplink.logging.level.sql" value="FINE"/>
            
     
   
 
 
Cascade refresh query hint for refresh query 
 TLE provides the query hint toplink.refresh to fetch up-to-date entities from database like below.
     Query query = em.createQuery("SELECT e FROM Employee e WHERE e.id = :id");
    query.setHint("toplink.refresh", "true");
The associated entities will be refreshed also if they are specified with cascade=REFRESH. However the cascade metadata is static configuration which can not be changed in runtime and there may be some cases to apply different cascade options - do not cascade or cascade to all associations from time to time regardless of predefined cascade option. That is, more dynamic cascade refresh option can be useful. Hence I added the following query hint.

                              Query hint
              Description
            
                     toplink.refresh.cascade
                       Control whether associated entities are refreshed.
         
         The following are the valid values for the oracle.toplink.essentials.config.CascadePolicy:
                                 NoCascading - do not cascade at all
           
                        CascadePrivateParts - cascade to private-owned associations
           
                        CascadeAllParts - cascade to all associations
           
                        CascadeByMapping - cascade by mapping metadata
           
         
         
         Default is CascadeByMapping
         
                    Example:          
         import oracle.toplink.essentials.config.TopLinkQueryHints;
import oracle.toplink.essentials.config.CascadePolicy;
query.setHint(TopLinkQueryHints.REFRESH_CASCADE, CascadePolicy.CascadeAllParts);

or

query.setHint("toplink.refresh.cascade", "CascadeAllParts");
         NOTE: This applies only if toplink.refresh is set to TRUE.
            
     
   
 
 
At this time CascadePrivateParts option has no difference from CascadeAllParts for Java Persistence Entity, but when using underlying TopLink feature this could behave different in the future.
 
Other existing properties and query hints are documented in http://www.oracle.com/technology/products/ias/toplink/JPA/essentials/toplink-jpa-extensions.html 

 Have fun with this enhancements and please comment how you feel.

[1] GlassFish Issue#1338
 [2] GlassFish Issue#3269


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Wonseok Kim

TopLink Essentials enhancements - category-specific logging level and cascade refresh query hint

Category-specific logging level

Cascade refresh query hint for refresh query