Package org.apache.sis.referencing.factory

Class IdentifiedObjectSet<T extends org.opengis.referencing.IdentifiedObject>

java.lang.Object
java.util.AbstractCollection<T>
java.util.AbstractSet<T>
org.apache.sis.referencing.factory.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 org.opengis.referencing.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
Version:
0.7
Author:
Martin Desruisseaux (IRD, Geomatys)

  • Field Details

    • factory

      protected final org.opengis.referencing.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(org.opengis.referencing.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 org.opengis.referencing.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 org.opengis.referencing.IdentifiedObject>
      Specified by:
      clear in interface Set<T extends org.opengis.referencing.IdentifiedObject>
      Overrides:
      clear in class AbstractCollection<T extends org.opengis.referencing.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 org.opengis.referencing.IdentifiedObject>
      Specified by:
      size in interface Set<T extends org.opengis.referencing.IdentifiedObject>
      Specified by:
      size in class AbstractCollection<T extends org.opengis.referencing.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.
      Purpose: 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 org.opengis.referencing.IdentifiedObject>
      Specified by:
      add in interface Set<T extends org.opengis.referencing.IdentifiedObject>
      Overrides:
      add in class AbstractCollection<T extends org.opengis.referencing.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 org.opengis.referencing.IdentifiedObject>
      Specified by:
      contains in interface Set<T extends org.opengis.referencing.IdentifiedObject>
      Overrides:
      contains in class AbstractCollection<T extends org.opengis.referencing.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 org.opengis.referencing.IdentifiedObject>
      Specified by:
      remove in interface Set<T extends org.opengis.referencing.IdentifiedObject>
      Overrides:
      remove in class AbstractCollection<T extends org.opengis.referencing.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 org.opengis.referencing.IdentifiedObject>
      Specified by:
      removeAll in interface Set<T extends org.opengis.referencing.IdentifiedObject>
      Overrides:
      removeAll in class AbstractSet<T extends org.opengis.referencing.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 org.opengis.referencing.IdentifiedObject>
      Specified by:
      iterator in interface Iterable<T extends org.opengis.referencing.IdentifiedObject>
      Specified by:
      iterator in interface Set<T extends org.opengis.referencing.IdentifiedObject>
      Specified by:
      iterator in class AbstractCollection<T extends org.opengis.referencing.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 org.opengis.util.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:
      org.opengis.util.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 org.opengis.util.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:
      org.opengis.util.FactoryException - if the object creation failed.

    • isRecoverableFailure

      protected boolean isRecoverableFailure(org.opengis.util.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:

      • If NoSuchAuthorityCodeException, returns false since failure to find a code declared in the collection would be an inconsistency. Note that this exception is a subtype of NoSuchIdentifierException, so it must be tested before the last case below.
      • If NoSuchIdentifierException, returns true since this exception is caused by an attempt to create a parameterized transform for an unimplemented operation.
      • If MissingFactoryResourceException, returns true.
      • Otherwise returns false.
      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.