Geographical - Spatial Index

Services

The geo index is implemented through three services, in the same manner as the full text index. They are all implemented according to the Factory pattern:

• The GeoIndexManagement Service represents an index manager. There is a one to one relationship between an Index and a Management instance, and their life-cycles are closely related; an Index is created by creating an instance (resource) of GeoIndexManagement Service, and an index is removed by terminating the corresponding GeoIndexManagement resource. The GeoIndexManagement Service should be seen as an interface for managing the life-cycle and properties of an Index, but it is not responsible for feeding or querying its index. In addition, a GeoIndexManagement Service resource does not store the content of its Index locally, but contains references to content stored in Content Management Service.
• The GeoIndexBatchUpdater Service is responsible for feeding an Index. One GeoIndexBatchUpdater Service resource can only update a single Index, but one Index can be updated by multiple GeoIndexBatchUpdater Service resources. Feeding is accomplished by instantiating a GeoIndexBatchUpdater Service resources with the EPR of the GeoIndexManagement resource connected to the Index to update, and connecting the updater resource to a ResultSet containing the content to be fed to the Index.
• The GeoIndexLookup Service is responsible for creating a local copy of an index, and exposing interfaces for querying and creating statistics for the index. One GeoIndexLookup Service resource can only replicate and lookup a single instance, but one Index can be replicated by any number of GeoIndexLookup Service resources. Updates to the Index will be propagated to all GeoIndexLookup Service resources replicating that Index.

It is important to note that none of the three services have to reside on the same node; they are only connected through WebService calls and the DILIGENT CMS. The following illustration shows the information flow and responsibilities for the different services used to implement the Geo Index:

(illustration will be improved shortly... )

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