org.deegree.crs.configuration.deegree
Class DeegreeCRSProvider

java.lang.Object
  org.deegree.crs.configuration.AbstractCRSProvider<Element>
      org.deegree.crs.configuration.deegree.DeegreeCRSProvider

All Implemented Interfaces:

CRSProvider

public class DeegreeCRSProvider
extends AbstractCRSProvider<Element>

The DeegreeCRSProvider reads the deegree crs-config (based on it's own xml-schema) and creates the CRS's (and their datums, conversion info's, ellipsoids and projections) if requested.

Attention, although urn's are case-sensitive, the deegreeCRSProvider is not. All incoming id's are toLowerCased!

Automatic loading of projection/transformation classes

It is possible to create your own projection/transformation classes, which can be automatically loaded.

You can achieve this loading by supplying the class attribute to a crs:projectedCRS/crs:projection or crs:coordinateSystem/crs:transformation element in the 'deegree-crs-configuration.xml'. This attribute must contain the full class name (with package), e.g. <crs:projection class='my.package.and.projection.Implementation'>

Because the loading is done with reflections your classes must sustain following criteria:

Projections

1. It must be a sub class of Projection
2. A constructor with following signature must be supplied:
   public MyProjection(
    GeographicCRS underlyingCRS,
    double falseNorthing,
    double falseEasting,
    javax.vecmath.Point2d naturalOrigin,
    Unit units,
    double scale,
    java.util.List<org.w3c.dom.Element> yourProjectionElements
);


   The first six parameters are common to all projections (for an explanation of their meaning take a look at Projection). The last list, will contain all xml-dom elements you supplied in the deegree configuration (child elements of the crs:projection/crs:MyProjection), thus relieving you of the parsing of the deegree-crs-configuration.xml document.

Transformations

1. It must be a sub class of PolynomialTransformation
2. A constructor with following signature must be supplied:
   public MyTransformation(
    java.util.list<Double> aValues,
    java.util.list<Double> bValues,
    CoordinateSystem targetCRS,
    java.util.List<org.w3c.dom.Element> yourTransformationElements
);


   The first three parameters are common to all polynomial values (for an explanation of their meaning take a look at PolynomialTransformation). Again, the last list, will contain all xml-dom elements you supplied in the deegree configuration (child elements of the crs:transformation/crs:MyTransformation), thus relieving you of the parsing of the deegree-crs-configuration.xml document.

Version:

$Revision: 18308 $, $Date: 2009-07-02 14:40:19 +0200 (Do, 02. Jul 2009) $

Author:

Rutger Bezema, last edited by: $Author: rbezema $

Nested Class Summary

Nested classes/interfaces inherited from class org.deegree.crs.configuration.AbstractCRSProvider

AbstractCRSProvider.SupportedProjectionParameters, AbstractCRSProvider.SupportedProjections, AbstractCRSProvider.SupportedTransformationParameters, AbstractCRSProvider.SupportedTransformations

Constructor Summary

DeegreeCRSProvider(Properties properties)

Method Summary

boolean	canExport()
void	export(StringBuilder sb, List<CoordinateSystem> crsToExport) Exports the crs to the implemented format.
List<String>	getAvailableCRSIds() This method should be called if one is only interested in the available identifiers and not in the coordinatesystems themselves.
List<CoordinateSystem>	getAvailableCRSs() This method should be called to see if the provider is able to create all defined crs's, thus verifying the correctness of the configuration.
Identifiable	getIdentifiable(String id) This method is more general than the CRSProvider.getCRSByID(String), because it represents a possibility to return an arbitrary Identifiable Object from the providers backend.
CRSParser	getResolver()
Transformation	getTransformation(CoordinateSystem sourceCRS, CoordinateSystem targetCRS) This method is should retrieve a transformation (chain) which transforms coordinates from the given source into the given target crs.
protected CoordinateSystem	parseCoordinateSystem(Element crsDefinition)
Transformation	parseTransformation(Element transformationDefinition)

Methods inherited from class org.deegree.crs.configuration.AbstractCRSProvider

addIdToCache, clearCache, getCachedIdentifiable, getCachedIdentifiable, getCachedIdentifiable, getCachedIdentifiable, getCRSByID, mapProjectionParameters, mapProjections, mapTransformation, mapTransformationParameters, setResolver

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DeegreeCRSProvider

public DeegreeCRSProvider(Properties properties)
                   throws CRSConfigurationException

Parameters:

properties - containing information about the crs resource class and the file location of the crs configuration. If either is null the default mechanism is using the CRSParser and the deegree-crs-configuration.xml

Throws:

CRSConfigurationException - if the give file or the default-crs-configuration.xml file could not be loaded.

Method Detail

canExport

public boolean canExport()

Returns:

true if this provider can export a given crs.

export

public void export(StringBuilder sb,
                   List<CoordinateSystem> crsToExport)

Description copied from interface: CRSProvider

Exports the crs to the implemented format. Try calling CRSProvider.canExport() before executing this method.

Parameters:

sb - the StringBuilder which will contain the exported version of the given crs.

crsToExport - the CoordinateSystems to export.

See Also:

CRSProvider.canExport()

getResolver

public CRSParser getResolver()

Overrides:

getResolver in class AbstractCRSProvider<Element>

Returns:

the casted resolver of the super class.

getAvailableCRSIds

public List<String> getAvailableCRSIds()
                                throws CRSConfigurationException

Description copied from interface: CRSProvider

This method should be called if one is only interested in the available identifiers and not in the coordinatesystems themselves.

Returns:

the identifiers of all configured CRSs.

Throws:

CRSConfigurationException - if the implementation was confronted by an exception and could not deliver the requested crs. This exception should not be thrown if no CoordinateSystems were found, in the latter case an empty List ( a list with size == 0 ) should be returned.

getAvailableCRSs

public List<CoordinateSystem> getAvailableCRSs()
                                        throws CRSConfigurationException

Description copied from interface: CRSProvider

This method should be called to see if the provider is able to create all defined crs's, thus verifying the correctness of the configuration.

Returns:

all configured CRSs.

Throws:

CRSConfigurationException - if the implementation was confronted by an exception and could not deliver the requested crs. This exception should not be thrown if no CoordinateSystems were found, in the latter case an empty List ( a list with size == 0 ) should be returned.

getIdentifiable

public Identifiable getIdentifiable(String id)
                             throws CRSConfigurationException

Description copied from interface: CRSProvider

This method is more general than the CRSProvider.getCRSByID(String), because it represents a possibility to return an arbitrary Identifiable Object from the providers backend.

Parameters:

id - string representation of the resource to retrieve

Returns:

the Identifiable Object or null if no such Object was found.

Throws:

CRSConfigurationException - if the implementation was confronted by an exception and could not deliver the requested Object. This exception should not be thrown if the given id wasn't found, in this case null should be returned.

parseCoordinateSystem

protected CoordinateSystem parseCoordinateSystem(Element crsDefinition)
                                          throws CRSConfigurationException

Specified by:

parseCoordinateSystem in class AbstractCRSProvider<Element>

Parameters:

crsDefinition - containing the definition of a crs in the understood type.

Returns:

a CoordinateSystem instance initialized with values from the given type definition fragment or null if the given crsDefinition is null or not known.

Throws:

CRSConfigurationException - if an error was found in the given crsDefintion

parseTransformation

public Transformation parseTransformation(Element transformationDefinition)
                                   throws CRSConfigurationException

Specified by:

parseTransformation in class AbstractCRSProvider<Element>

Parameters:

transformationDefinition - containing the parameters needed to build a Transformation.

Returns:

a Transformation instance initialized with values from the given definition or null if the given transformationDefintion is null. If the parsed transformation is not supported or a NotSupportedTransformation will be returned.

Throws:

CRSConfigurationException - if an error was found in the given crsDefintion

getTransformation

public Transformation getTransformation(CoordinateSystem sourceCRS,
                                        CoordinateSystem targetCRS)
                                 throws CRSConfigurationException

Description copied from interface: CRSProvider

This method is should retrieve a transformation (chain) which transforms coordinates from the given source into the given target crs. If no such transformation could be found or the implementation does not support inverse lookup of transformations null should be returned.

Parameters:

sourceCRS - start of the transformation (chain)

targetCRS - end point of the transformation (chain).

Returns:

the Transformation Object or null if no such Object was found.

Throws:

CRSConfigurationException - if the implementation was confronted by an exception and could not deliver the requested Object. This exception should not be thrown no Transformation was found, in this case null should be returned.