org.gvsig.remoteclient.wfs

Class WFSClient

java.lang.Object

org.gvsig.remoteclient.RemoteClient

org.gvsig.remoteclient.wfs.WFSClient

public class WFSClient
extends RemoteClient

Represents the class the with the necessary logic to connect to a OGCWFS and interpretate the data

Author:

Jorge Piera Llodrá (piera_jor@gva.es)

Field Summary

Fields inherited from class org.gvsig.remoteclient.RemoteClient

hostName, port, serviceName

Constructor Summary

Constructors

Constructor and Description
WFSClient(java.lang.String host) Constructor.
WFSClient(java.lang.String host, java.lang.String version)

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Does ...
boolean	connect(boolean override, org.gvsig.compat.net.ICancellable cancel) Checks the connection to de remote WFS and requests its capabilities.
boolean	connect(org.gvsig.compat.net.ICancellable cancel)
java.io.File	describeFeatureType(WFSStatus status, boolean override, org.gvsig.compat.net.ICancellable cancel) The function of the DescribeFeatureType operation is to generate a schema description of feature types serviced by a WFS implementation.
void	getCapabilities(WFSStatus status, boolean override, org.gvsig.compat.net.ICancellable cancel) Every OGC Web Service (OWS), including a Web Feature Service, must have the ability to describe its capabilities by returning service metadata in response to a GetCapabilities request.
WFSFeature	getFeature(java.lang.String nameSpace, java.lang.String localName)
java.io.File	getFeature(WFSStatus status, boolean override, org.gvsig.compat.net.ICancellable cancel) The GetFeature operation allows retrieval of features from a web feature service.
java.util.Hashtable	getFeatures() Returns the features list
WFSRequestInformation	getLastWfsRequestInformation()
WFSServiceInformation	getServiceInformation() Gets the Service information included in the Capabilities
java.lang.String	getVersion()
WFSRequestInformation	getWFSRequestInformationAt(int index) Return the information of a request
int	getWFSRequestInformationCount()
void	lockFeature(WFSStatus status, boolean override, org.gvsig.compat.net.ICancellable cancel) Web connections are inherently stateless.
void	transaction(WFSStatus status, boolean override, org.gvsig.compat.net.ICancellable cancel) The Transaction operation is used to describe data transformation operations that are to be applied to web accessible feature instances.

Methods inherited from class org.gvsig.remoteclient.RemoteClient

getHost, getPort, getServiceName, getSubtype, getType, setHost, setPort, setServiceName, setSubtype, setType

Methods inherited from class java.lang.Object

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

Constructor Detail

WFSClient

public WFSClient(java.lang.String host)
          throws java.net.ConnectException,
                 java.io.IOException

Constructor. the parameter host, indicates the WFS host to connect.

Throws:

ConnectException,IOException

java.net.ConnectException

java.io.IOException

WFSClient

public WFSClient(java.lang.String host,
         java.lang.String version)
          throws java.io.IOException

Throws:

java.io.IOException

Method Detail

close

public void close()

Description copied from class: RemoteClient

Does ...

Specified by:

close in class RemoteClient

connect

public boolean connect(boolean override,
              org.gvsig.compat.net.ICancellable cancel)

Checks the connection to de remote WFS and requests its capabilities.

Specified by:

connect in class RemoteClient

connect

public boolean connect(org.gvsig.compat.net.ICancellable cancel)

describeFeatureType

public java.io.File describeFeatureType(WFSStatus status,
                               boolean override,
                               org.gvsig.compat.net.ICancellable cancel)
                                 throws WFSException

The function of the DescribeFeatureType operation is to generate a schema description of feature types serviced by a WFS implementation. The schema descriptions define how a WFS implementation expects feature instances to be encoded on input (via Insert and Update requests) and how feature instances will be generated on output (in response to GetFeature and GetGmlObject requests).

Parameters:

status - WFS client status. Contains all the information to create the query

Throws:

WFSException

getCapabilities

public void getCapabilities(WFSStatus status,
                   boolean override,
                   org.gvsig.compat.net.ICancellable cancel)
                     throws WFSException

Every OGC Web Service (OWS), including a Web Feature Service, must have the ability to describe its capabilities by returning service metadata in response to a GetCapabilities request.

Parameters:

status - WFS client status. Contains all the information to create the query

Throws:

WFSException

getFeature

public WFSFeature getFeature(java.lang.String nameSpace,
                    java.lang.String localName)

getFeature

public java.io.File getFeature(WFSStatus status,
                      boolean override,
                      org.gvsig.compat.net.ICancellable cancel)
                        throws WFSException

The GetFeature operation allows retrieval of features from a web feature service. A GetFeature request is processed by a WFS and when the value of the outputFormat attribute is set to text/gml a GML instance document, containing the result set, is returned to the client.

Parameters:

status - WFS client status. Contains all the information to create the query

Returns:

File GML File

Throws:

WFSException

getFeatures

public java.util.Hashtable getFeatures()

Returns the features list

Returns:

getLastWfsRequestInformation

public WFSRequestInformation getLastWfsRequestInformation()

Returns:

the lastWfsRequestInformation

getServiceInformation

public WFSServiceInformation getServiceInformation()

Gets the Service information included in the Capabilities

getVersion

public java.lang.String getVersion()

getWFSRequestInformationAt

public WFSRequestInformation getWFSRequestInformationAt(int index)

Return the information of a request

Parameters:

index - The position of the request

Returns:

getWFSRequestInformationCount

public int getWFSRequestInformationCount()

Returns:

the number requests

lockFeature

public void lockFeature(WFSStatus status,
               boolean override,
               org.gvsig.compat.net.ICancellable cancel)
                 throws WFSException

Web connections are inherently stateless. As a consequence of this, the semantics of serializable transactions are not preserved. To understand the issue, consider an update operation. The client fetches a feature instance. The feature is then modified on the client side, and submitted back to the database via a Transaction request for update. Serializability is lost since there is nothing to guarantee that while the feature was being modified on the client side, another client did not come along and update that same feature in the database. One way to ensure serializability is to require that access to data be done in a mutually exclusive manner; that is while one transaction accesses a data item, no other transaction can modify the same data item. This can be accomplished by using locks that control access to the data. The purpose of the LockFeature operation is to expose a long term feature locking mechanism to ensure consistency. The lock is considered long term because network latency would make feature locks last relatively longer than native commercial database locks. The LockFeature operation is optional and does not need to be implemented for a WFS implementation to conform to this specification. If a WFS implements the LockFeature operation, this fact must be advertised in the capabilities document

Parameters:

status -

Throws:

WFSException

transaction

public void transaction(WFSStatus status,
               boolean override,
               org.gvsig.compat.net.ICancellable cancel)
                 throws WFSException

The Transaction operation is used to describe data transformation operations that are to be applied to web accessible feature instances. A web feature service may process a Transaction operation directly or possibly translate it into the language of a target datastore to which it is connected and then have the datastore execute the transaction. When the transaction has been completed, a web feature service will generate an XML response document indicating the completion status of the transaction.

Parameters:

status - WFS client status. Contains all the information to create the query

Throws:

WFSException