provide parsers in a consistent fashion - STEMLab/geotools GitHub Wiki

Description

We have both some text parsing (CQL and WKT) and XML parsing (filter, gml) incoming. This proposal outlines how we can be consistent in terms of package structure.

  • CQL - Catalogue Query Language - currently an unsupported module
  • XML - Extensible Markup Language - we are forced to run our own parser due to scaling issues
  • WKT - Well Known Text - we already support CRS definition, we need one for Parsing Geometry

How can we be consistent:

  1. Make a "default" useful parser available as a utility class

    • CQL
    • CRS.parseWKT
    • JTS.parseWKT
    • Spatial.parseWKT (should be method compatible with JTS utility class)

  2. Hide details in a parser package (that casual users do not need to import)

  3. Be consistent with package names (not sure how to handle version differences)

    • org.geotools.filter.text.cql2 - parser code for CQL
    • org.geotools.geometry.text.wkt - parser code for WKT
    • org.geotools.filter.xml.filter1_0 - filter 1.0 bindings (requires gml2)
    • org.geotools.filter.xml.filter1_1 - Filter 1.1 bindings (requires gml3)
    • org.geotools.geometry.xml.gml2 - geometry bindings for latest GML2
    • org.geotools.geometry.xml.gml3 - geometry bindings for latest GML3

package names for the gory details

Of the format org.geotools.SUBJECT.PARSER.SPECIFICATION:

  • SUBJECT - is the output being produced (ie style, geometry, referencing, feature, filter, etc...)
  • PARSER - is the kind of "input" being considered (ie text or xml )
  • SPECIFICATION - (optional) if you need to get more specific on the kind of "input" you can quote the specification here.

Please note this is for the gory details only; your users should not have to import anything from these packages. You may be stuck making some of the content public (especially for XML callbacks) - but none of your example/user code should be forced into an import.

:warning: Module breakdown of xml binding plugins is not in scope - we would need a seperate proposal.

Status

Voting in process - closes April 2nd.

Discussed on the email list and in a weekly IRC meeting ( 2007/03/19/IRC Meeting - 19 March 2007).

Votes are currently being collected:

It would be nice to have this approved this week so the work can be in the release this month.

Tasks

        | :white_check_mark: | :no_entry: | :warning:               | :negative_squared_cross_mark: |

------------|--------------------|------------|-------------------------|-------------------------------| no progress | done | impeded | lack mandate/funds/time | volunteer needed |

A target release is also provided for each milestone.

Milestone 1

2.4-M1

:white_check_mark:

Move cql to library

:white_check_mark:

Added org.geotools.geometry.WKTParser

:white_check_mark:

test and release

:white_check_mark:

update documentation

Milestone 2

2.5-M1

test and release

update documentation

Milestone 3

2.5.0

verify user documentation

include in release

API Changes

BEFORE

This change introduces new API:

Example.java

public void exampleMethod( ... ){
     Point point = primitiveFactory.createPoint( 32.0, 32.0 );
}

AFTER

Example.java

import org.geotools.geometry.iso.Spatial;

// holds the WKT parser but is not needed by client code
// import org.geotools.geometry.text.wkt 

/**
 * Note geometryFactory includes CRS information already
 */
public void exampleMethod( ... ){
    Spatial spatial = new Spatial( geometryFactory, primitiveFactory, positionFactory );
    Point = (Point) Spatial.parseWKT( "POINT 32 32" );
}

Documentation Changes

Website:

  • Update Upgrade to 2.4 instructions (if xml parsing packages are changed)

Developers Guide:

  • Update description package convention to describe how additional parsers can be added.

User Guide:

  • CQL examples look great!
  • CRS examples needed
  • Spatial examples needed

User Manual:

  • Check with Acuster to see if demo can be updated

Issue Tracker:

  • Close jira when completed