Class WFSDataAccessFactory

  • All Implemented Interfaces:
    DataAccessFactory, Factory
    Direct Known Subclasses:

    public class WFSDataAccessFactory
    extends Object
    implements DataAccessFactory
    The factory responsible for creating WFSDataAccess objects based on their capabilities and the configuration file used. This file is included as a candidate for DataAccessFinder by virtue of the fact that its name is present in the file gt-wfs-ng > src/main/resources > META-INF > services >
    Adam Brown (Curtin University of Technology)
    • Constructor Detail

      • WFSDataAccessFactory

        public WFSDataAccessFactory()
    • Method Detail

      • canProcess

        public boolean canProcess​(Map<String,​?> params)
        Checks whether params contains a valid set of parameters to connect to a WFS.

        Rules are:

        Specified by:
        canProcess in interface DataAccessFactory
        params - The full set of information needed to construct a live data source.
        booean true if and only if this factory can process the resource indicated by the param set and all the required params are pressent.
      • canProcess

        protected boolean canProcess​(Map<String,​?> params,
                                     int maximumGmlComplianceLevel)
      • createDataStore

        public DataAccess<? extends FeatureType,​? extends Feature> createDataStore​(Map<String,​?> params)
                                                                                  throws IOException
        Description copied from interface: DataAccessFactory
        Construct a live DataAccess using the connection parameters provided.

        You can think of this class as setting up a connection to the back end data source. The required parameters are described by the getParameterInfo() method.

        Magic Params: the following params are magic and are honoured by convention by the GeoServer and uDig application.

        • "user": is taken to be the user name
        • "passwd": is taken to be the password
        • "namespace": is taken to be the namespace prefix (and will be kept in sync with GeoServer namespace management.
        When we eventually move over to the use of OpperationalParam we will have to find someway to codify this convention.
        Specified by:
        createDataStore in interface DataAccessFactory
        params - The full set of information needed to construct a live data store. Typical key values for the map include: url - location of a resource, used by file reading datasources. dbtype - the type of the database to connect to, e.g. postgis, mysql
        The created DataStore, this may be null if the required resource was not found or if insufficent parameters were given. Note that canProcess() should have returned false if the problem is to do with insuficent parameters.
        IOException - if there were any problems setting up (creating or connecting) the datasource.
      • getDescription

        public String getDescription()
        Description copied from interface: DataAccessFactory
        Describe the nature of the datasource constructed by this factory.

        A non localized description of this data store type.

        Specified by:
        getDescription in interface DataAccessFactory
        A human readable description that is suitable for inclusion in a list of available datasources.
      • getImplementationHints

        public Map<RenderingHints.Key,​?> getImplementationHints()
        Description copied from interface: Factory
        Map of hints (maybe unmodifiable) used by this factory to customize its use. This map is not guaranteed to contains all the hints supplied by the user; it may be only a subset. Consequently, hints provided here are usually not suitable for creating new factories, unless the implementation make some additional garantees.

        The primary purpose of this method is to determine if an existing factory instance can be reused for a set of user-supplied hints. This method is invoked by FactoryRegistry in order to compare this factory's hints against user's hints. This is dependency introspection only; FactoryRegistry never invokes this method for creating new factories.

        Keys are usually static constants from the Hints class, while values are instances of some key-dependent class. The key set must contains at least all hints impacting functionality. While the key set may contains all hints supplied by the user, it is recommended to limit the set to only the hints used by this particular factory instance. A minimal set will helps FactoryRegistry to compare only hints that matter and avoid the creation of unnecessary instances of this factory.

        The hint values may be different than the one supplied by the user. If a user supplied a hint as a Class object, this method shall replace it by the actual instance used, if possible.

        Implementations of this method are usually quite simple. For example if a datum authority factory uses an ordinary datum factory, its method could be implemented as below (note that we should not check if the datum factory is null, since key with null value is the expected behaviour in this case). Example:

         Map hints = new HashMap();
         hints.put(Hints.DATUM_FACTORY, datumFactory);
         return hints;
        Specified by:
        getImplementationHints in interface Factory
        The map of hints, or an {@linkplain java.util.Collections.emptyMap() empty map} if none.
      • getDisplayName

        public String getDisplayName()
        Description copied from interface: DataAccessFactory
        Name suitable for display to end user.

        A non localized display name for this data store type.

        Specified by:
        getDisplayName in interface DataAccessFactory
        A short name suitable for display in a user interface.
      • isAvailable

        public boolean isAvailable()
        Description copied from interface: DataAccessFactory
        Test to see if the implementation is available for use. This method ensures all the appropriate libraries to construct the DataAccess are available.

        Most factories will simply return true as GeoTools will distribute the appropriate libraries. Though it's not a bad idea for DataStoreFactories to check to make sure that the libraries are there.

        OracleDataStoreFactory is an example of one that may generally return false, since GeoTools can not distribute the oracle jars. (they must be added by the client.)

        One may ask how this is different than canProcess, and basically available is used by the DataStoreFinder getAvailableDataStore method, so that DataStores that can not even be used do not show up as options in gui applications.

        Specified by:
        isAvailable in interface DataAccessFactory
        true if and only if this factory has all the appropriate jars on the classpath to create DataStores.