org.geotools.feature
Class FeatureTypeImpl

java.lang.Object
  org.geotools.feature.FeatureTypeImpl

All Implemented Interfaces:

FeatureType

public class FeatureTypeImpl

extends java.lang.Object

implements FeatureType

This is a sample implementation of the FeatureType API.

The suffix implementation is used to indicat this is a direct, straight forward implementation of the associated interface.

This serves as, my reference implementation, if you have any questions please contact me (jgarnett@refractions.net) or jump on the geotools-devel email list. There is a good chance my understanding is wrong, I expect and want feedback on this implementation.

I especially am interested in:

• XPATH - xpath is used to locate AttributeTyp instances. Does this even work? FeatureType captures schema information, you cannot do an xpath query based on

  Author:

  Jody Garnett, Refractions Research

  Constructor Summary

  protected

  FeatureTypeImpl(java.net.URI namespace, java.lang.String typeName, boolean isAbstract, AttributeType[] attributeTypes, GeometryAttributeType defaultGeometry, FeatureType[] ancestors) No direct construction is "Allowed", please use a FeatureTypeBuilder as per design.

  Method Summary

  Feature	create(java.lang.Object[] attributes) Scheduled for removal in Geotools 2.2, please use FeatureFactory.
  Feature	create(java.lang.Object[] attributes, java.lang.String featureID) Scheduled for removal in Geotools 2.2, please use FeatureFactory.
  Feature	duplicate(Feature feature) Create a duplicate of the provided feature, must delegate to an appropriate FeatureFactory create method.
  boolean	equals(java.lang.Object arg0) FeatureType check based on namespace, typeName, attributes and ancestors.
  int	find(AttributeType type) Find the position of a given AttributeType.
  int	find(java.lang.String attName) Find the position of an AttributeType which matches the given String.
  FeatureType[]	getAncestors() Obtain an array of this FeatureType's direct ancestors.
  int	getAttributeCount() This produces the number of distinct featuretypes avaialble via this schema.
  AttributeType	getAttributeType(int position) Gets the schema attributeType at the specified index.
  AttributeType	getAttributeType(java.lang.String xPath) Gets the attributeType at this xPath, if the specified attributeType does not exist then null is returned.
  AttributeType[]	getAttributeTypes() AttributeTypes for this FeatureType, all attributes defined by this FeatureType and its super types define schema for feature instances.
  GeometryAttributeType	getDefaultGeometry() Gets the default geometry AttributeType.
  java.net.URI	getNamespace() Gets the global schema namespace.
  java.lang.String	getTypeName() Gets the type name for this schema.
  boolean	hasAttributeType(java.lang.String xPath) This is only used twice in the whole geotools code base, and one of those is for a test, so we're removing it from the interface.
  boolean	isAbstract() Is this FeatureType an abstract type?
  boolean	isDescendedFrom(FeatureType type) This method is implemented by a straight reference to FeatureTypes isDecendedFrom( typeA, typeB ).
  boolean	isDescendedFrom(java.net.URI namespace, java.lang.String typeName) This method is implemented by a straight reference to FeatureTypes isDecendedFrom( type, namespace, typename ).

  Methods inherited from class java.lang.Object

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

  Methods inherited from interface org.geotools.feature.FeatureType

  hashCode

  Constructor Detail

  FeatureTypeImpl

  protected FeatureTypeImpl(java.net.URI namespace,
                            java.lang.String typeName,
                            boolean isAbstract,
                            AttributeType[] attributeTypes,
                            GeometryAttributeType defaultGeometry,
                            FeatureType[] ancestors)

  No direct construction is "Allowed", please use a FeatureTypeBuilder as per design.

  This interface is *not* marked as final, however every last field is bolted down as private final. Any subclass is stuck using the API, this is negotiable - things are locked down so you have to email me (jgarnett@refractions.net), cause I suspect if you need to change something we should have an API discussion and consider broader changes. (Consider this a volunteer recuritment practice).

  Responsibilities:

  • Implement FeatureType
  • Document the needs of people extending FeatureTypeImpl for a "custom use".
  • Generate email discussion about FeatureType API issues.

  Since:

  2.1.0

  Method Detail

  equals

  public boolean equals(java.lang.Object arg0)

  Description copied from interface: FeatureType

  FeatureType check based on namespace, typeName, attributes and ancestors.

  Conceptually FeatureType equality is supped to indicate an exact match based AttributeType and Ancestors. The geotools models includes additional information of namespace and typename.

  As far as the geotools data model is concerned any FeatureType implementation should be able to be subsituted for another. (An actually application may provided an implementation that provdes tracking of metadata such as creation history, or support for additional interfaces).

  Required implementation:

  A sample implementation is provided in FeatureTypes.equals( FeatureType, FeatureType ).

  Questions:
  Q: You may wonder why namespace and typeName are not enought?
  A: Geotools often returns a "limitied" schema in response to a query where only a subset of the attributes are requested.
  Q: Doesn't that still indicate the same schema?
  A: Yes it kind of should, a GML application (such as GeoServer) has to actually follow the application schema and include attributes required by the schema (but not request by the query). This library is more lax in its treatment, and expects you to uses isDecendedFrom as required.

  Specified by:

  equals in interface FeatureType

  getNamespace

  public java.net.URI getNamespace()

  Description copied from interface: FeatureType

  Gets the global schema namespace.

  This is often used to record the schema prefix (not the URI) required when writing out this Feature using GML. The supporting application will need to be able to start the GMLWriter off with the correct URI information so everything makes sense.

  The Registry interface provided by the data module provides an example of how to store associate FeatureType and namespace information. Please note that you may not have duplicate typeNames in the same Namespace.

  Specified by:

  getNamespace in interface FeatureType

  Returns:

  Namespace of schema

  getTypeName

  public java.lang.String getTypeName()

  Description copied from interface: FeatureType

  Gets the type name for this schema.

  In GML this must be the element name of the Feature.

  Specified by:

  getTypeName in interface FeatureType

  Returns:

  The name of this feature type.

  isDescendedFrom

  public boolean isDescendedFrom(java.net.URI namespace,
                                 java.lang.String typeName)

  This method is implemented by a straight reference to FeatureTypes isDecendedFrom( type, namespace, typename ).

  Please consider this a query of this FeatureType's ancestors. For specific modules like GML they may want to do a bit more magic here, not especially encouraged but the API allows for it.

  Specified by:

  isDescendedFrom in interface FeatureType

  Parameters:

  namespace - The namespace URI to use.

  typeName - The typeName.

  Returns:

  true if descendant, false otherwise.

  See Also:

  FeatureType.isDescendedFrom(java.net.URI, java.lang.String)

  isDescendedFrom

  public boolean isDescendedFrom(FeatureType type)

  This method is implemented by a straight reference to FeatureTypes isDecendedFrom( typeA, typeB ).

  Specified by:

  isDescendedFrom in interface FeatureType

  Parameters:

  type - The type to compare to.

  Returns:

  true if descendant, false otherwise.

  See Also:

  FeatureType.isDescendedFrom(org.geotools.feature.FeatureType)

  isAbstract

  public boolean isAbstract()

  Description copied from interface: FeatureType

  Is this FeatureType an abstract type?

  When true is returned instances of this Feature cannot be created, instead a child FeatureType must use this FeatureType as its ancestor.

  Specified by:

  isAbstract in interface FeatureType

  Returns:

  true if abstract, false otherwise.

  getAncestors

  public FeatureType[] getAncestors()

  Description copied from interface: FeatureType

  Obtain an array of this FeatureType's direct ancestors. Implementors should return a non-null array (may be of length 0).

  • length 0 - a root FeatureType
  • length 1 - singe inhieratance
  • length 1+ - multiple inheiratance, order is not significant

  GetAncestors() indicates *just* the direct parents of this FeatureType. It capures the inheirtance relationship from the OGC overview document.

  Example Code:

  
   public FeatureType getAncestors()}
       return new FeatureType[]{ getSuper(), };
   }
   

  Specified by:

  getAncestors in interface FeatureType

  Returns:

  An array of ancestors.

  getDefaultGeometry

  public GeometryAttributeType getDefaultGeometry()

  Description copied from interface: FeatureType

  Gets the default geometry AttributeType.

  If the FeatureType has more one geometry it is up to the implementor to determine which geometry is the default. If working with multiple geometries it is best to get the attributeTypes and iterate through them, checking for instances of GeometryAttribtueType.

  This should just be used a convenience method when it is known that the features do not have multiple geometries.

  Specified by:

  getDefaultGeometry in interface FeatureType

  Returns:

  The attribute type of the default geometry, which will contain the position.

  getAttributeCount

  public int getAttributeCount()

  This produces the number of distinct featuretypes avaialble via this schema.

  Specified by:

  getAttributeCount in interface FeatureType

  Returns:

  number of distinct attributeTypes available, taking ancestors and taking overrides into account.

  See Also:

  FeatureType.getAttributeCount()

  getAttributeType

  public AttributeType getAttributeType(java.lang.String xPath)

  Description copied from interface: FeatureType

  Gets the attributeType at this xPath, if the specified attributeType does not exist then null is returned.

  Question: it is unclear how this interacts with the complete schema defined by this FeatureType and its ancestors (in which a given xpath may refer to several AttributeTypes as restrictions are applied.

  Perhaps this method should be restricted to a FlatFeatureType? Or should have the option of returning an array of matching AttributeType in order of inheiritence?

  Specified by:

  getAttributeType in interface FeatureType

  Parameters:

  xPath - XPath pointer to attribute type.

  Returns:

  AttributeType, or null if unavaialble

  find

  public int find(AttributeType type)

  Description copied from interface: FeatureType

  Find the position of a given AttributeType.

  Match is based on attribute type name, the resulting index may be used with getAttributeType( index ).

  Specified by:

  find in interface FeatureType

  Parameters:

  type - The type to search for.

  Returns:

  -1 if not found, a zero-based index if found.

  find

  public int find(java.lang.String attName)

  Description copied from interface: FeatureType

  Find the position of an AttributeType which matches the given String.

  This index may be used with getAttributeType( index ), the search space is the entire schema defined by this FeatureType and its ancestors.

  Specified by:

  find in interface FeatureType

  Parameters:

  attName - the name to look for

  Returns:

  -1 if not found, zero-based index otherwise

  getAttributeType

  public AttributeType getAttributeType(int position)

  Description copied from interface: FeatureType

  Gets the schema attributeType at the specified index.

  The index is specified with respect to the entire Schema (as defined by this FeatureType and it's ancestors).

  The index value should not be used with either:
  • FeatureType.getAttributeTypes()[index] - as it defines only attributes contributed by this FeatureType
  • Feature.getAttribute( index ) - as attributes order may or may not be in sequence

  Specified by:

  getAttributeType in interface FeatureType

  Returns:

  The attribute type at the specified position.

  getAttributeTypes

  public AttributeType[] getAttributeTypes()

  Description copied from interface: FeatureType

  AttributeTypes for this FeatureType, all attributes defined by this FeatureType and its super types define schema for feature instances.

  The provided array of AttributeTypes should be considered as adding to (or overriding) the the AttribtueTypes defined by this FeatureTypes ancestors.

  Note Well: Client code should not consider the index provided by the find( attName ) method as a valid index into the returned array.

  Specified by:

  getAttributeTypes in interface FeatureType

  Returns:

  Array of AttributeType describing this schema, array may be length 0, but should not be null

  hasAttributeType

  public boolean hasAttributeType(java.lang.String xPath)

  Description copied from interface: FeatureType

  This is only used twice in the whole geotools code base, and one of those is for a test, so we're removing it from the interface. If getAttributeType does not have the AttributeType it will just return null. Gets the number of occurrences of this attribute.

  Question: the comment says we are removing this, but it is not depricated? And how the heck can the number of occurances out of a boolean.

  Specified by:

  hasAttributeType in interface FeatureType

  Parameters:

  xPath - XPath pointer to attribute type.

  Returns:

  Number of occurrences.

  duplicate

  public Feature duplicate(Feature feature)
                    throws IllegalAttributeException

  Description copied from interface: FeatureType

  Create a duplicate of the provided feature, must delegate to an appropriate FeatureFactory create method.

  The implementation is assumed to make use of AttributeType duplicate as required for a deep copy.

  Specified by:

  duplicate in interface FeatureType

  Parameters:

  feature -

  Returns:

  a deep copy of feature

  Throws:

  IllegalAttributeException

  create

  public Feature create(java.lang.Object[] attributes)
                 throws IllegalAttributeException

  Description copied from interface: FeatureType

  Scheduled for removal in Geotools 2.2, please use FeatureFactory.

  Creates a new feature, with a generated unique featureID. This is less than ideal, as a FeatureID should be persistant over time, generally created by a datasource. This method is more for testing that doesn't need featureID.

  Specified by:

  create in interface FeatureType

  Parameters:

  attributes - the array of attribute values

  Returns:

  The created feature

  Throws:

  IllegalAttributeException - if the FeatureType does not validate the attributes.

  create

  public Feature create(java.lang.Object[] attributes,
                        java.lang.String featureID)
                 throws IllegalAttributeException

  Description copied from interface: FeatureType

  Scheduled for removal in Geotools 2.2, please use FeatureFactory.

  Creates a new feature, with the proper featureID.

  Specified by:

  create in interface FeatureType

  Parameters:

  attributes - the array of attribute values.

  featureID - the feature ID.

  Returns:

  the created feature.

  Throws:

  IllegalAttributeException - if the FeatureType does not validate the attributes.