org.deegree.portal.standard.wfs.control
Class GeometryValidator

java.lang.Object
  org.deegree.enterprise.control.AbstractListener
      org.deegree.portal.standard.wfs.control.GeometryValidator

All Implemented Interfaces:

EventListener, WebListener

public class GeometryValidator
extends AbstractListener

This listener validates simple geometries. The geometries to be validated are passed in as the value of the 'GEOMETRY' parameter of such an RPC request:

   <methodCall>
   <methodName>dig:checkGeometry</methodName>
   <params>
   <param><value><struct><member>
   <name>GEOMETRY</name>
   <value><string>POLYGON(( 7.38 49.64, 12.03 48.7, 11.34 51.66, 11.34 51.66, 7.38 49.64 ))</string></value>
   </member></struct></value></param>
   </params>
   </methodCall>
 

Subclasses may override validateRequest( RPCWebEvent rpcEvent ), createGeometry( RPCWebEvent rpcEvent ) and/or validateGeometry() if they want to change the behaviour regarding request validation, geometry creation and/or geometry validation, respectively. Especially the last method may be different according to use-cases. The result of the validation is put in the session under the key GeometryValidator.GEOMETRY_STATE.

Version:

$Revision: 18195 $, $Date: 2009-06-18 17:55:39 +0200 (Do, 18. Jun 2009) $

Author:

Ugo Taddei, last edited by: $Author: mschneider $

Field Summary

protected Geometry	geometry
static String	GEOMETRY_STATE Attribute name for the geometry validity state
static String	INFORMALLY_VALID_GEOMETRY Indicates that the geometry is OK, although it may not be considered formally correct in most GIS contexts.
static String	INVALID_GEOMETRY Indicates that the geometry is invalid (self intersection, missing points, etc)
static String	VALID_GEOMETRY Indicates that the geometry is perfectly valid

Constructor Summary

GeometryValidator()

Method Summary

void	actionPerformed(FormEvent event) This method validates the RPC-encoded request (validateRequest(RPCWebEvent)), create some geometry from the request parameters (createGeometry(RPCWebEvent) and then validate this geometry (validateGeometry().
protected Geometry	createGeometry(RPCWebEvent rpcEvent) Creates the geometry from the data provided it the request (rpcEvent).
protected Object	validateGeometry() Validates this object's Geometry and return an object, preferably a code, indicating the validity state of the geometry.
protected void	validateRequest(RPCWebEvent rpcEvent) Validates the incoming RPc request.

Methods inherited from class org.deegree.enterprise.control.AbstractListener

getAlternativeNextPage, getHomePath, getInitParameter, getInitParameterList, getNextPage, getRequest, getReturnValue, gotoErrorPage, handle, setAlternativeNextPage, setDefaultAlternativeNextPage, setDefaultNextPage, setNextPage, setReturnValue, toModel

Methods inherited from class java.lang.Object

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

Field Detail

GEOMETRY_STATE

public static final String GEOMETRY_STATE

Attribute name for the geometry validity state

See Also:

Constant Field Values

VALID_GEOMETRY

public static final String VALID_GEOMETRY

Indicates that the geometry is perfectly valid

See Also:

Constant Field Values

INVALID_GEOMETRY

public static final String INVALID_GEOMETRY

Indicates that the geometry is invalid (self intersection, missing points, etc)

See Also:

Constant Field Values

INFORMALLY_VALID_GEOMETRY

public static final String INFORMALLY_VALID_GEOMETRY

Indicates that the geometry is OK, although it may not be considered formally correct in most GIS contexts.

See Also:

Constant Field Values

geometry

protected Geometry geometry

Constructor Detail

GeometryValidator

public GeometryValidator()

Method Detail

actionPerformed

public void actionPerformed(FormEvent event)

This method validates the RPC-encoded request (validateRequest(RPCWebEvent)), create some geometry from the request parameters (createGeometry(RPCWebEvent) and then validate this geometry (validateGeometry(). The result of this validate is made available to the request object as an attribute under the key GeometryValidator.GEOMETRY_STATE.

Specified by:

actionPerformed in interface WebListener

Specified by:

actionPerformed in class AbstractListener

Parameters:

event - the event containing the RPC-emcoded request.

validateRequest

protected void validateRequest(RPCWebEvent rpcEvent)
                        throws Exception

Validates the incoming RPc request. This method looks for an RPC parameter (struct) named 'GEOMETRY', checks if the valeu is empty and looks no further. The expected value is a well-known geometry representation.

Parameters:

rpcEvent - the event containing at least a struct with a string type parameter named 'GEOMETRY'.

Throws:

Exception - If no such parameter is found or if the value is empty. This is interpreted as an exception and the resulting message is sent back to the client.

createGeometry

protected Geometry createGeometry(RPCWebEvent rpcEvent)
                           throws Exception

Creates the geometry from the data provided it the request (rpcEvent).

Parameters:

rpcEvent - the RPCWebEvent conatining the request

Returns:

a new geometry. This method uses WKTAdapter.wrap(String, org.deegree.model.crs.CoordinateSystem) to create the new Geometry.

Throws:

Exception - if the Geometry creation failed.

See Also:

validateRequest(RPCWebEvent)

validateGeometry

protected Object validateGeometry()

Validates this object's Geometry and return an object, preferably a code, indicating the validity state of the geometry. There are three type of geometry validity states.

• GeometryValidator.VALID_GEOMETRY: The geometry is perfecly OK,
• GeometryValidator.INVALID_GEOMETRY: The geometry is not OK (self intersection, missing points, etc),
• GeometryValidator.INFORMALLY_VALID_GEOMETRY: The geometry is OK, although it may not be considered formally correct in most GIS contexts. For example, polygons are supposed to have counter-clockwise outter rings, lines may no self-intersect, etc.

The meaning of those may also vary according to the use-case, e.g. a polygon that is counter-clockwise but is required to have at least 4 vertices.
This method employs the Java Topology Suite to check for geometry validity (Geometry.isValid()) and, in the case of polygons, for the order of the coordinates (in other words, whether they are counter-clockwise}.
The result of the validation is available in the request under the key GeometryValidator.GEOMETRY_STATE.

Returns:

the geometry's validity state