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

Class IdentifiedObjectSet<T extends IdentifiedObject>

Object
AbstractCollection<T>
AbstractSet<T>
IdentifiedObjectSet<T>
Type Parameters:
T - the type of objects to be included in this set.
All Implemented Interfaces:
Iterable<T>, Collection<T>, Set<T>, Checked­Container<T>, Localized
public class IdentifiedObjectSet<T extends IdentifiedObject> extends AbstractSet<T> implements CheckedContainer<T>, Localized
A lazy set of Identified­Object instances created from their authority codes only when first needed. This set delegates Identified­Object creation to the most appropriate create­Foo(String) method of the Authority­Factory given at construction time.

Elements can be added to this collection with calls to add­Authority­Code(String) for deferred object creation, or to add(Identified­Object) for objects that are already instantiated. This collection cannot contain two Identified­Object instances having the same identifier. However, the identifiers used by this class can be controlled by overriding get­Authority­Code(Identified­Object).

Iterations over elements in this collection preserve insertion order.

Purpose

Identified­Object­Set can be used as the set returned by implementations of the Geodetic­Authority­Factory​.create­From­Coordinate­Reference­System­Codes(String, String) method. Deferred creation can have great performance impact since some set may contain as much as 40 entries (e.g. transformations from "ED50" (EPSG:4230) to "WGS 84" (EPSG:4326)) while some users only want to look for the first entry.

Exception handling

If the underlying factory failed to creates an object because of an unsupported operation method (No­Such­Identifier­Exception), the exception is logged at Level​.WARNING and the iteration continue. If the operation creation failed for any other kind of reason (Factory­Exception), then the exception is re-thrown as an unchecked Backing­Store­Exception. This default behavior can be changed by overriding the is­Recoverable­Failure(Factory­Exception) method.

Thread safety

This class is thread-safe is the underlying factory is also thread-safe. However, implementers are encouraged to wrap in unmodifiable set if they intent to cache Identified­Object­Set instances.
Since:
0.7

  • Field Details

    • factory

      protected final AuthorityFactory factory
      The factory to use for creating Identified­Objects when first needed. This is the authority factory given at construction time.

  • Constructor Details

    • IdentifiedObjectSet

      public IdentifiedObjectSet(AuthorityFactory factory, Class<T> type)
      Creates an initially empty set. The set can be populated after construction by calls to add­Authority­Code(String) for deferred Identified­Object creation, or to add(Identified­Object) for already instantiated objects.
      Parameters:
      factory - the factory to use for deferred Identified­Object instances creation.
      type - the type of objects included in this set.

  • Method Details

    • getLocale

      public Locale getLocale()
      Returns the locale to use for error messages and warnings. The default implementation inherits the factory locale, if any.
      Specified by:
      get­Locale in interface Localized
      Returns:
      the locale, or null if not explicitly defined.

    • getElementType

      public Class<T> getElementType()
      Returns the type of Identified­Object included in this set.
      Specified by:
      get­Element­Type in interface Checked­Container<T extends Identified­Object>
      Returns:
      the type of Identified­Object included in this set.

    • clear

      public void clear()
      Removes all of the elements from this collection.
      Specified by:
      clear in interface Collection<T extends Identified­Object>
      Specified by:
      clear in interface Set<T extends Identified­Object>
      Overrides:
      clear in class Abstract­Collection<T extends Identified­Object>

    • size

      public int size()
      Returns the number of objects available in this set. Note that this number may decrease during the iteration process if the creation of some Identified­Objects failed.
      Specified by:
      size in interface Collection<T extends Identified­Object>
      Specified by:
      size in interface Set<T extends Identified­Object>
      Specified by:
      size in class Abstract­Collection<T extends Identified­Object>
      Returns:
      the number of objects available in this set.

    • getAuthorityCodes

      public String[] getAuthorityCodes()
      Returns the authority codes of all Identified­Objects contained in this collection, in insertion order. This method does not trig the creation of any object.
      Returns:
      the authority codes in iteration order.

    • setAuthorityCodes

      public void setAuthorityCodes(String... codes)
      Sets the content of this collection to the object identified by the given codes. For any code in the given sequence, this method will preserve the corresponding Identified­Object instance if it was already created. Otherwise objects will be created only when first needed.

      Use case

      This method is typically used together with get­Authority­Codes() for altering the iteration order on the basis of authority codes. If the specified codes sequence contains the same elements than the ones in the array returned by get­Authority­Codes() but in a different order, then this method just sets the new ordering.
      Parameters:
      codes - the authority codes of identified objects to store in this set.
      See Also:

    • addAuthorityCode

      public void addAuthorityCode(String code)
      Ensures that this collection contains an object for the specified authority code. If this collection does not contain any element for the given code, then this method will instantiate an Identified­Object for the given code only when first needed. Otherwise this collection is unchanged.
      Parameters:
      code - the code authority code of the Identified­Object to include in this set.

    • add

      public boolean add(T object)
      Ensures that this collection contains the specified object. This collection does not allow multiple objects for the same authority code. If this collection already contains an object using the same authority code than the given object, then the old object is replaced by the new one regardless of whether the objects themselves are equal or not.
      Specified by:
      add in interface Collection<T extends Identified­Object>
      Specified by:
      add in interface Set<T extends Identified­Object>
      Overrides:
      add in class Abstract­Collection<T extends Identified­Object>
      Parameters:
      object - the object to add to the set.
      Returns:
      true if this set changed as a result of this call.
      See Also:

    • contains

      public boolean contains(Object object)
      Returns true if this collection contains the specified Identified­Object.
      Specified by:
      contains in interface Collection<T extends Identified­Object>
      Specified by:
      contains in interface Set<T extends Identified­Object>
      Overrides:
      contains in class Abstract­Collection<T extends Identified­Object>
      Parameters:
      object - the Identified­Object to test for presence in this set.
      Returns:
      true if the given object is presents in this set.

    • remove

      public boolean remove(Object object)
      Removes the specified Identified­Object from this collection, if it is present.
      Specified by:
      remove in interface Collection<T extends Identified­Object>
      Specified by:
      remove in interface Set<T extends Identified­Object>
      Overrides:
      remove in class Abstract­Collection<T extends Identified­Object>
      Parameters:
      object - the Identified­Object to remove from this set.
      Returns:
      true if this set changed as a result of this call.

    • removeAll

      public boolean removeAll(Collection<?> collection)
      Removes from this collection all of its elements that are contained in the specified collection.
      Specified by:
      remove­All in interface Collection<T extends Identified­Object>
      Specified by:
      remove­All in interface Set<T extends Identified­Object>
      Overrides:
      remove­All in class Abstract­Set<T extends Identified­Object>
      Parameters:
      collection - the Identified­Objects to remove from this set.
      Returns:
      true if this set changed as a result of this call.

    • iterator

      public Iterator<T> iterator() throws BackingStoreException
      Returns an iterator over the objects in this set. If the iteration encounter any kind of Factory­Exception other than No­Such­Identifier­Exception, then the exception will be re-thrown as an unchecked Backing­Store­Exception.

      This iterator is not thread safe – iteration should be done in a single thread. However, the iterator is robust to concurrent changes in Identified­Object­Set during iteration.

      Specified by:
      iterator in interface Collection<T extends Identified­Object>
      Specified by:
      iterator in interface Iterable<T extends Identified­Object>
      Specified by:
      iterator in interface Set<T extends Identified­Object>
      Specified by:
      iterator in class Abstract­Collection<T extends Identified­Object>
      Returns:
      an iterator over all Identified­Object instances in this set, in insertion order.
      Throws:
      Backing­Store­Exception - if an error occurred while creating the iterator.

    • resolve

      public void resolve(int n) throws FactoryException
      Ensures that the n first objects in this set are created. This method can be invoked for making sure that the underlying factory is really capable to create at least one object. Factory­Exception (except the ones accepted as recoverable failures) are thrown as if they were never wrapped into Backing­Store­Exception.
      Parameters:
      n - the number of object to resolve. If this number is equal or greater than size(), then this method ensures that all Identified­Object instances in this collection are created.
      Throws:
      Factory­Exception - if an object creation failed.

    • getAuthorityCode

      protected String getAuthorityCode(T object)
      Returns the identifier for the specified object. The default implementation takes the first of the following identifier which is found:
      1. An identifier allocated by the authority given by factory.get­Authority().
      2. The first object identifier, regardless its authority.
      3. The first object name, regardless its authority.
      Subclasses may override this method if they want to use a different identifiers.
      Parameters:
      object - the object for which to get the authority code.
      Returns:
      the authority code of the given identified object.

    • createObject

      protected T createObject(String code) throws FactoryException
      Creates an object for the specified authority code. This method is invoked during the iteration process if an object was not already created.
      Parameters:
      code - the code for which to create the identified object.
      Returns:
      the identified object created from the given code.
      Throws:
      Factory­Exception - if the object creation failed.

    • isRecoverableFailure

      protected boolean isRecoverableFailure(FactoryException exception)
      Returns true if the specified exception should be handled as a recoverable failure. This method is invoked during the iteration process if the factory failed to create some objects. If this method returns true for the given exception, then the exception will be logged at Level​.WARNING. If this method returns false, then the exception will be re-thrown as a Backing­Store­Exception.

      The default implementation applies the following rules:

      Parameters:
      exception - the exception that occurred while creating an object.
      Returns:
      true if the given exception should be considered recoverable, or false if it should be considered fatal.