Built-in Extended Types

VB provides a few built-in 'extended' types that extend from some base types provided by JET (for example, JET ArrayDataProvider) or implement an interface (JET DataProvider), and, most importantly, that use the VB Extended Type mechanism so that these types are VB aware. These VB types are generally used with a VB variable.

Authors can also use the same Extended Type mechanism to write Custom Extended Types.

VB provides these built-in extended types:

• Service Data Provider

  This built-in extended type represents a data provider that fetches data from a service endpoint and that can be bound to listView, table and other collection components that can bind to a DataProvider implementation. It encapsulates various capabilities such as filtering, sorting, pagination, and fetch and allows externalizing fetches to an actionChain.

• Multi-Service Data Provider

  JET components that bind to data providers like oj-combobox-one / oj-select-single (or the -many variants) often use different 'fetch' capabilities. Example, a oj-select-single component calls fetchFirst() (on the DataProvider implementation) to populate its options, in addition to fetchByKeys() to fetch data for selected value and fetchByOffset. This built-in extended type is a dataProvider implementation that combines multiple ServiceDataProvider variables, each providing a unique fetch capability.

• Array Data Provider 2

  This extended builtin type is a data provider implementation where the data is available as an array. Generally with vb/ArrayDataProvider2 (similar to vb/ArrayDataProvider) all the data is set once, the data itself can fetched from a backend service (say a list of countries) as it is assumed that array once created is static, i.e. data changes infrequently or has limited/infrequent adds/updates and removes done to it.

• Array Data Provider (Legacy)

  This extended type uses the JET oj.ArrayDataProvider implementation, which is based on the DataProvider interface, and whose data is a plain array. The properties on the variable of type vb/ArrayDataProvider generally mirror the JET ADP's properties.