Module org.apache.sis.referencing
Package org.apache.sis.referencing.factory

Class IdentifiedObjectFinder

Object
IdentifiedObjectFinder
public class IdentifiedObjectFinder extends Object
Searches in an authority factory for objects approximately equal to a given object. This class can be used for fetching a fully defined identified object from an incomplete one, for example from an object without "ID[…]" or "AUTHORITY[…]" element in Well Known Text.

The steps for using Identified­Object­Finder are:

  1. Get a new instance by calling Geodetic­Authority­Factory​.new­Identified­Object­Finder().
  2. Optionally configure that instance by calling its setter methods.
  3. Perform a search by invoking the find(Identified­Object) or find­Singleton(Identified­Object) method.
  4. The same Identified­Object­Finder instance can be reused for consecutive searches.

Thread safety

Identified­Object­Finder are not guaranteed to be thread-safe even if the underlying factory is thread-safe. If concurrent searches are desired, then a new instance should be created for each thread.
Since:
0.7
See Also:

  • Field Details

    • factory

      protected final AuthorityFactory factory
      The factory to use for creating objects. This is the factory specified at construction time.

  • Constructor Details

  • Method Details

    • getSearchDomain

      public IdentifiedObjectFinder.Domain getSearchDomain()
      Returns the domain of the search (for example whether to include deprecated objects in the search). If DECLARATION, only a fast lookup based on embedded identifiers and names will be performed. Otherwise an exhaustive full scan against all registered objects will be performed (may be slow).

      The default value is Identified­Object­Finder​.Domain​.VALID_DATASET.

      Returns:
      the domain of the search.

    • setSearchDomain

      public void setSearchDomain(IdentifiedObjectFinder.Domain domain)
      Sets the domain of the search (for example whether to include deprecated objects in the search). If this method is never invoked, then the default value is Identified­Object­Finder​.Domain​.VALID_DATASET.
      Parameters:
      domain - the domain of the search.

    • isIgnoringAxes

      public boolean isIgnoringAxes()
      Returns true if the search should ignore coordinate system axes. The default value is false.
      Returns:
      true if the search should ignore coordinate system axes.

    • setIgnoringAxes

      public void setIgnoringAxes(boolean ignore)
      Sets whether the search should ignore coordinate system axes. If this property is set to true, then the search will compare only the coordinate system type and dimension. The axis names, orientation and units will be ignored. For example, the find(…) method may return a Coordinate Reference System object with (latitude, longitude) axes even if the given object had (longitude, latitude) axes.
      Parameters:
      ignore - true if the search should ignore coordinate system axes.

    • find

      public Set<IdentifiedObject> find(IdentifiedObject object) throws FactoryException
      Lookups objects which are approximately equal to the specified object. The default implementation tries to instantiate some identified objects from the authority factory specified at construction time, in the following order:
      • If the specified object contains identifiers associated to the same authority than the factory, then those identifiers are used for creating objects to be tested.
      • If the authority factory can create objects from their name in addition of identifiers, then the name and aliases are used for creating objects to be tested.
      • If a full scan of the dataset is allowed, then full set of candidate codes is used for creating objects to be tested.
      The created objects which are equal to the specified object in the the sense of Comparison­Mode​.APPROXIMATE are returned.
      Parameters:
      object - the object looked up.
      Returns:
      the identified objects, or an empty set if not found.
      Throws:
      Factory­Exception - if an error occurred while creating an object.

    • findSingleton

      public IdentifiedObject findSingleton(IdentifiedObject object) throws FactoryException
      Lookups only one object which is approximately equal to the specified object. This method invokes find(Identified­Object), then examine the returned Set as below:
      • If the set is empty, then this method returns null.
      • If the set contains exactly one element, then this method returns that element.
      • If the set contains more than one element, but only one element has the same axis order than object and all other elements have different axis order, then this method returns the single element having the same axis order.
      • Otherwise this method considers that there is ambiguity and returns null.
      Parameters:
      object - the object looked up.
      Returns:
      the identified object, or null if none or ambiguous.
      Throws:
      Factory­Exception - if an error occurred while creating an object.

    • getCodeCandidates

      protected Set<String> getCodeCandidates(IdentifiedObject object) throws FactoryException
      Returns a set of authority codes that may identify the same object than the specified one. The returned set must contains at least the code of every objects that are approximately equal to the specified one. However, the set may conservatively contains the code for more objects if an exact search is too expensive.

      This method is invoked by the default find(Identified­Object) method implementation. The caller iterates through the returned codes, instantiate the objects and compare them with the specified one in order to determine which codes are really applicable. The iteration stops as soon as a match is found (in other words, if more than one object is equal to the specified one, then the find(…) method selects the first one in iteration order).

      Default implementation

      The default implementation returns the same set than get­Authority­Codes(type) where type is the interface specified at construction type. Subclasses should override this method in order to return a smaller set, if they can.
      Parameters:
      object - the object looked up.
      Returns:
      a set of code candidates.
      Throws:
      Factory­Exception - if an error occurred while fetching the set of code candidates.