Enterprise Software Design Blog

Archive for the ‘Extensibility Framework’ Category

As discussed in my earlier post(Extensibility Design), an extensible design provides the ability to customize an enterprise application software to server business needs of different customers. Extensibility is critical to the application software vendor especially if the software is delivered through a SaaS or On-Demand model. The underlying application architecture should support a metadata based model, which will provide a framework to extend the out of the box application to suite different customers’ needs. The framework should provide a generalized mechanism to construct application components to build the software.

The generalized mechanism for extensibility will mainly provide following three features.

  • Data Model Extensibility: The end users should be able to manage attributes with in a business objects. They should be able to add a new attribute of any data type and define rules for it.
  • UI Extensibility: The end users should be able to add new attribute to the UI forms as a field and the data can be added/modified using these fields. The field can be either simple editable text, number (such as amount, percentage), lookup or even media object (such as image, video) etc.,
  • Security Privileges: The design should take in to account that can extend a business object and once extended who can view and manage these extended attribute.

Data Model Extensibility

Data model extensibility is achieved through flexible attributes. Flexible attributes are generic attributes that is associated with a logical business objects. Flexible attributes are of generic data type (such as Raw) and can hold data of any type. The data will be stored as raw bytes and will be converted to appropriate data type on the business layer before transaction processing. An example of flexible attribute for CRM Opportunity object is given below.

UI Extensibility

UI Extensibility refers to the ability to add a field on runtime to a page. A ‘customize’ link will bring up the extensibility editor which will allow the users to create a new field in the form. The editor will prompt the user to enter the label and type. The types can either text, number of lookup. If lookup is chosen, then the editor will prompt the user to enter the lookup items. The user can also choose other properties such as required field and validation rules (not shown in wireframe below).

Security Privileges

The visibility of extended attributes and fields will depend on the security privileges. The attributes in the data model will inherit the data security policy defined for the logical business object and the function security will depend on any of the following.

  • Organization Hierarchy: The field can be made visible to the any of the organization hierarchy defined such as sales org, marketing organization etc.,
  • Employee Hierarchy: The field can be made visible to the any of the employee hierarchy defined. The administrator will choose a sales VP and all employees reporting under sales VP will see the fields.
  • All Users: The field can be made visible to all the uses with in a enterprise.

It should be noted that in a SaaS model, the customization will be visible only to those who extends the product. Subscribers’ from other customers will not be able to see these changes.

Enterprise Software products are unique and generally different organizations use it differently. It will be rare or impossible to see enterprise software used without modifications by enterprises. A typical enterprise has unique needs based on their organization structure and they customize the software available off the shelf. They hire functional and technical consultants, who have expert level knowledge of underlying technology and functionality to perform these customizations. The nature of customization could be either simple UI change, data model change or it could even more complex such as behavioral change (i.e. configuring workflows, adding business rules etc.,) or third party integrations. The consultants will typically make changes to the application source code and would require source code maintenance with the enterprise.

With the emergence of SaaS delivery model and multi-tenancy needed to achieve economies of scale, software customization for individual is not a viable option. The vendor will not be able to maintain versions of software for every customer and with software available on cloud the enterprises cannot maintain source code in house. At the same time, customers should be able to extend the product functionality to suit their needs. Software extensibility framework helps software to be customization without a need to change the underlying source code. A good extensibility framework design will allow the end users to customize the software and these customization will be visible only in the instance which the customer is accessing.

An extensible design can be categorized as following.

  • UI Extensibility: The user interface layer should be extensible and the customer should be able to customize the look and feel of the application. This customization can range from changing colors, application branding (i.e. changing logos), changing widgets look and feel and advanced customization such as customizing label texts, show/hide UI widgets, customizing error messages etc.,
  • Data Model Extensibility: The end users should be able to extend the data model for any object. They should be able to add a new field to the form and add data to it. The field can be of any data type including the multimedia content. The application should allow for defining validation rules and lookup values. Note that the data model extensibility generally doesn’t allow for creating data model or re-defining object relationships.
  • Workflow Extensibility: A typical business process consists of a workflow that is sequence of connected steps helps complete a task. The extensibility should allow the end users to configure these workflow steps (i.e. add/delete a step), define business rules, add notifications etc.,

I will discuss each of these with an example in my subsequent posts.


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