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Motivation:

There is a need for an extensible API to query the datastore about what it can do (and adding a delete method in the process)

Contact:

Andrea Aime

Tracker:

http://jira.codehaus.org/browse/GEOT-XXXX

Tagline:

Datastore capabilities

Description

Dealing with datastores often means adding instanceof and try/catch blocks around the code to figure out what the data store can - actually do. There is no straight way to query the datastore about simple things like:

  • is it possible to create a new feature type?
  • is it possible to update a feature type?
  • is type "xyz" read only? Can we do locking on top of it?
  • what are the data types supported by a certain store?
  • how is createSchema going to mangle the feature type definition provided by the user?

In most of the cases to actually know if something is supported one has actually to try to do it, which is bad as requires to add un-necessary try/catch blocks and does not allow to inspect the capabilities to build a proper user interface with only the available commands.

This proposal tries to address the above by introducing a new class, DataCapabilities, that can be used to perform the above questions. The DataAccess interface will be extended by adding a new method:

where DataCapabilities is defined as:

DataCapabilities has been defined as a class so that it can be extended in the future without breaking the API.

Status

This proposal is under construction.

Voting has started:

Tasks

This section is used to make sure your proposal is complete (did you remember documentation?) and has enough paid or volunteer time lined up to be a success

 

no progress

(tick)

done

(error)

impeded

(warning)

lack mandate/funds/time

(question)

volunteer needed

  1. API changed based on BEFORE / AFTER
  2. Update default implementation
  3. Update wiki (both module matrix and upgrade to to 2.5 pages) |
  4. Remove deprecated code from GeoTools project
  5. Update the user guide
  6. Update or provided sample code in demo
  7. review user documentation

API Changes

BEFORE

This is some bits of code trying to create a schema and then trying to insert some data

AFTER

By quering the capabilities it's possible to know in advance what can be done without
having to actually try to do it, meaning it's possible to build a GUI that only has the
operations that are actually available.

Documentation Changes

We may need to update the demos.

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