Technical

Datasources and selections allow the Atlas user to apply a filter to the content they want to show on a website. The plugins in the system, which build these two components start with com.tetracom.atlas.datasource, com.tetracom.atlas.selection and com.tetracom.atlas.contentitem.selection . The datasource entity is a group of content item property clauses, linked with a logical operation (AND or OR). A datasource restricts the content items in a list to the ones, which meet certain criteria. An example datasource filter is:

( Book.title contains Rings

OR

Book.author contains Tolkien)

AND

Book.publication_year greater than 1910

This filer is based on a content type Book with two text properties – title and author, as well as a number property which indicates the year of publication of a book. The datasource contains three clauses :

1. The title of the book should contain the word Rings

2. The name of the author of the book should contain Tolkien

3. The book's publication year should be after 1910.

The brackets and the logical operations identify that:

Either Clause 1 or Clause 2 (or both) should be satisfied. Clause 3 must be satisfied in all cases. To summarize, the example above will filter the books, which are published after 1910 and either have Rings in their title or Tolkien in their author name.

A datasource clause is built of three components:

-a property – the content type property, which is used in the clause. Book.title, Book.author and Book.publication_year are the properties in the example above.

-an operator – the condition, which the property should meet. Contains and greater than are the operators in the example above.

-an operand – the value of the clause. Rings, Tolkien and 1910 are the clause values from the example.

The selection entity is actually a set of exact hand-picked content items, which are displayed in a list.

Important classes:

Datasource – the data filter business object with its properties, clauses and logical operations.

QueryRow – represents the datasource clause, defined above.

QueryRowLogicTerm – represents the logical operations(AND, OR).

EOperatorType – an enumeration, which includes the different operator types.

EoperandType – an enumeration, which includes the operand types in the system.

The selection entity is identified by these two business objects, which share the same proxy:

Selection – represents the selection business object.

SelectionContentItems – contains the ids of the content items, which participate in the selection.

Important services:

IDatasourceService – provides access to the datasource entity and all its properties.

ISelectionService, ISelectionContentItemsService – these two provide access to the selection entity and its content items.