Posted by
Jacques Le Roux on
URL: http://ofbiz.116.s1.nabble.com/Entity-Engine-tp4762160p4762161.html
Hi Xinhuan,
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Thanks
This said, some preliminary answers inline...
Jacques
Le 27/11/2020 à 22:38, Xinhuan Zheng a écrit :
> I started reading ofbiz documentation to be familiar with it. I look at the artifact document here:
https://cwiki.apache.org/confluence/display/OFBIZ/Framework+Introduction+Videos+and+Diagrams?preview=/7045155/14286869/18ArtRefDia.pdf> I'm truly amazed by this diagram.
>
> There is only (5) colored big boxes. Are they virtually serving as containers?
Not sure what you mean by containers here. If you think about Docker then no.
> For example, the Entity Engine serving as a container to produce entities, that can be created by physical SQL engine?
The Entity Engine is a mean to dialogue with a DBMS. But it's not an ORM[1] like Hibernate. Most of it is explained there:
https://cwiki.apache.org/confluence/display/OFBIZ/Entity+Engine+GuideJust saw your link below after reading all your email, you might also be interested by:
https://github.com/apache/ofbiz-framework/blob/trunk/framework/entity/config/entityengine.xmlThere is also a Service Engine. THey are the foundations of OFBiz:
https://cwiki.apache.org/confluence/display/OFBIZ/Service+Engine+Guide[1]
https://en.wikipedia.org/wiki/Object%E2%80%93relational_mapping> But what is this Entity Engine implementation?
It's pure plain OFBiz Java code. BTW, since its creation Atlassian Jira is using it underneath...!
> Is it a Tomcat container instance?
OFBiz embeds Tomcat[2]
[2]
https://www.theserverside.com/definition/embedded-Tomcat> I imagine Servlet Container to the top right of the diagram is implemented by Tomcat, is that right?
Yep
> The request flow is like a loop to me. The CS: Request: Event are fed into Control Servlet: Request part. What are the CS: Request: Event files and what are the control logic for this part to happen?
Controllers, it's XML code "driving" the requests, see OFBiz source:
https://github.com/apache/ofbiz-framework/blob/trunk/applications/product/webapp/catalog/WEB-INF/controller.xml>
> >From this document:
https://cwiki.apache.org/confluence/display/OFBIZ/Entity+Engine+Guide. The document said "The patterns used in the Entity Engine include: Business Delegate, Value Object, Composite Entity (variation), Value Object Assembler, Service Locator, and Data Access Object." The number of patterns is much less of the number of Entities to be managed? Is that all the patterns? Is there other reference that I can learn more about those Entity patterns?
For patterns globally there is
https://cwiki.apache.org/confluence/display/OFBIZ/OFBiz+Related+Books#OFBizRelatedBooks-CoreJ2EEPatternsBut specifically to the Entity Engine there is the "Extensibility Pattern", see:
https://cwiki.apache.org/confluence/display/OFBIZ/General+Entity+Overview#GeneralEntityOverview-ExtensibilityPatternHTH
Jacques
> Thank you,
>
> - Xinhuan