Compiere POJO Interfaces (XML, VO)

Compiere has a quite a few options to integrate with other applications.  Here, I want to concentrate on the Plain Old Java Object (POJO) interface options.  Other options to interface are via sql and various file formats.  In a future article, I will discus how to interface via JMS (e.g. to an Enterprise Service Bus (ESB)), SOAP and XML services. The Compiere Business Objects start with "M" based on the naming convention of the used Model-View-Controller Architecture.  The base persistence class PO.java has a bunch of methods which allow to build integrations to other sytems quickly.  The PO class is abstract and the typed access is provided by a generated class layer starting with X_{fileName}.  An example for illustration: 

• Table:  C_BPartner
• Generated Access Layer:  X_C_BPartner.java (extends PO.java)
• The Business functionality class :  MBPartner.java (extends X_C_BPartner.java)

There are vatious options how to create a business object.  The most common contructor use the context, primary key ID and the transaction:

• Ctx ctx = Env.getCtx();
• int C_BPartner_ID = 100;
• String trx = null; 
• MBPartner bp = new MBPartner(ctx, C_BPartner_ID, trx); 

From that you can create a w3c DOM document:

• boolean noComment = false;
• boolean dataOnly = false; 
• org.w3c.dom.Document doc = bp.get_xmlDocument(noComment, dataOnly);

You can also easily create a XML string:

• StringBuffer existingString = null; 
• StringBuffer bpXml = bp.get_xmlString(existingString, dataOnly); 

Compiere provides two formats - data only and with additional information.  The data only format only includes the data directly:

• <AD_Client_ID>11</AD_Client_ID>

For many applications the format with additional information is more appropriate for user facing applications, as you expect to see the de-referenced value (GardenWorld) and not the foreign key value (11):

• <AD_Client_ID>
    <Value>11</Value>
    <Label>Tenant</Label>
    <Info>GardenWorld</Info>
  </AD_Client_ID> 

Another base object for communications among systems are Value Objects or Transport Objects.  They are java beans with just setter and getter methods - but do not have any business functionality. The Compiere Implementation uses a class called VO.java.  From any business object you can create a value object:

• VO vo = bp.getVO(); 

You can also create a new business object from a VO, but that requires that you expose the PO constructor "public PO (Ctx ctx, VO vo)" - usually you would create a constructor as follows:

• public MMyClass (Ctx ctx, VO vo)
  {
      this(ctx, 0, null);
      load(vo);
  }

You can also use the utility class GenerateVO.java to create a value object with typed setters and getters - e.g. BPartnerVO. If you have any more questions, just contact me.