How to use

unmodifiableOrCopy

method

in

org.apache.sis.internal.util.CollectionsExt

  /**
   * Creates a new parameter descriptor for the given units.
   *
   * @param  units  the units.
   */
  public EPSGParameterDomain(final Set<Unit<?>> units) {
    super(Double.class, null, false, null, false);
    this.units = CollectionsExt.unmodifiableOrCopy(units);
  }
}

  /**
   * Creates a new parameter descriptor for the given units.
   *
   * @param  units  the units.
   */
  public EPSGParameterDomain(final Set<Unit<?>> units) {
    super(Double.class, null, false, null, false);
    this.units = CollectionsExt.unmodifiableOrCopy(units);
  }
}

/**
 * Returns a unmodifiable version of the given set.
 * This method is different than the standard {@link Collections#unmodifiableSet(Set)}
 * in that it tries to returns a more efficient object when there is zero or one element.
 * Such small set occurs frequently in Apache SIS, especially for
 * {@link org.apache.sis.referencing.AbstractIdentifiedObject} names or identifiers.
 *
 * <p><em>The set returned by this method may or may not be a view of the given set</em>.
 * Consequently this method shall be used <strong>only</strong> if the given set will
 * <strong>not</strong> be modified after this method call. In case of doubt, use the
 * standard {@link Collections#unmodifiableSet(Set)} method instead.</p>
 *
 * @param  <E>  The type of elements in the set.
 * @param  set  The set to make unmodifiable, or {@code null}.
 * @return A unmodifiable version of the given set, or {@code null} if the given set was null.
 */
public static <E> Set<E> unmodifiableOrCopy(Set<E> set) {
  return CollectionsExt.unmodifiableOrCopy(set);
}

/**
 * Returns a unmodifiable version of the given map.
 * This method is different than the standard {@link Collections#unmodifiableMap(Map)}
 * in that it tries to returns a more efficient object when there is zero or one entry.
 * Such small maps occur frequently in Apache SIS.
 *
 * <p><em>The map returned by this method may or may not be a view of the given map</em>.
 * Consequently this method shall be used <strong>only</strong> if the given map will
 * <strong>not</strong> be modified after this method call. In case of doubt, use the
 * standard {@link Collections#unmodifiableMap(Map)} method instead.</p>
 *
 * @param  <K>  The type of keys in the map.
 * @param  <V>  The type of values in the map.
 * @param  map  The map to make unmodifiable, or {@code null}.
 * @return A unmodifiable version of the given map, or {@code null} if the given map was null.
 */
public static <K,V> Map<K,V> unmodifiableOrCopy(Map<K,V> map) {
  return CollectionsExt.unmodifiableOrCopy(map);
}

/**
 * {@inheritDoc}
 */
@Override
public boolean transition(final State target) {
  final Collection<Identifier> p = identifiers;
  final boolean changed = super.transition(target);
  if (changed) {
    /*
     * The 'identifiers' collection will have been replaced by an unmodifiable collection if
     * subclass has an "identifiers" property. If this is not the case, then the collection
     * is unchanged (or null) so we have to make it unmodifiable here.
     */
    if (p != null && p == identifiers) {
      if (p instanceof Set<?>) {
        identifiers = CollectionsExt.unmodifiableOrCopy((Set<Identifier>) p);
      } else if (p instanceof List<?>) {
        identifiers = CollectionsExt.unmodifiableOrCopy((List<Identifier>) p);
      } else {
        identifiers = Collections.unmodifiableCollection(p);
      }
    }
  }
  return changed;
}

  set.remove(null);
return unmodifiableOrCopy(set);

  set.remove(null);
return unmodifiableOrCopy(set);

/**
 * Returns the code spaces of all factories given to the constructor.
 *
 * <div class="note"><b>Implementation note:</b>
 * the current implementation may be relatively costly since it implies instantiation of all factories.
 * </div>
 *
 * @return the code spaces of all factories.
 */
@Override
@SuppressWarnings("ReturnOfCollectionOrArrayField")
public Set<String> getCodeSpaces() {
  Set<String> union = codeSpaces;
  if (union == null) {
    union = new LinkedHashSet<>();
    for (final Iterator<AuthorityFactory> it = getAllFactories(); it.hasNext();) {
      union.addAll(getCodeSpaces(it.next()));
    }
    codeSpaces = union = CollectionsExt.unmodifiableOrCopy(union);
  }
  return union;
}

nodataValues = CollectionsExt.unmodifiableOrCopy(pads);

/**
 * Returns the code spaces of all factories given to the constructor.
 *
 * <div class="note"><b>Implementation note:</b>
 * the current implementation may be relatively costly since it implies instantiation of all factories.
 * </div>
 *
 * @return the code spaces of all factories.
 */
@Override
@SuppressWarnings("ReturnOfCollectionOrArrayField")
public Set<String> getCodeSpaces() {
  Set<String> union = codeSpaces;
  if (union == null) {
    union = new LinkedHashSet<>();
    for (final Iterator<AuthorityFactory> it = getAllFactories(); it.hasNext();) {
      union.addAll(getCodeSpaces(it.next()));
    }
    codeSpaces = union = CollectionsExt.unmodifiableOrCopy(union);
  }
  return union;
}

if (collection != null) {
  if (collection instanceof Set<?>) {
    return unmodifiableOrCopy((Set<E>) collection);

/**
 * Declares this metadata and all its properties as unmodifiable. Any attempt to modify a property
 * after this method call will throw an {@link org.apache.sis.metadata.UnmodifiableMetadataException}.
 * If this metadata is already unmodifiable, then this method does nothing.
 *
 * <p>Subclasses usually do not need to override this method since the default implementation
 * performs most of its work using Java reflection.</p>
 */
@Override
public void freeze() {
  if (isModifiable()) {
    final Collection<Identifier> p = identifiers;
    super.freeze();
    /*
     * The 'identifiers' collection will have been replaced by an unmodifiable collection if
     * subclass has an "identifiers" property. If this is not the case, then the collection
     * is unchanged (or null) so we have to make it unmodifiable here.
     */
    if (p == identifiers) {
      identifiers = CollectionsExt.unmodifiableOrCopy(p);                     // Null safe.
    }
  }
}

  i++;
memberIndices = CollectionsExt.unmodifiableOrCopy(memberIndices);
baseValueClass = (baseValueClass != null) ? Numbers.wrapperToPrimitive(baseValueClass) : Object.class;
return types;

/**
 * Stores the given result in the cache.
 * This method shall be invoked only when {@link #getSearchDomain()} is not {@link Domain#DECLARATION}.
 */
@Override
final Set<IdentifiedObject> cache(final IdentifiedObject object, Set<IdentifiedObject> result) {
  final Map<IdentifiedObject,FindEntry> findPool = ((ConcurrentAuthorityFactory<?>) factory).findPool;
  result = CollectionsExt.unmodifiableOrCopy(result);
  FindEntry entry = new FindEntry();
  synchronized (findPool) {
    final FindEntry c = findPool.putIfAbsent(object, entry);
    if (c != null) {
      entry = c;          // May happen if the same set has been computed in another thread.
    }
    // 'finder' should never be null since this method is not invoked directly by this Finder.
    result = entry.set(finder.isIgnoringAxes(), result, object == searching);
  }
  return result;
}

  i++;
memberIndices = CollectionsExt.unmodifiableOrCopy(memberIndices);
baseValueClass = (baseValueClass != null) ? Numbers.wrapperToPrimitive(baseValueClass) : Object.class;
return types;

components = CollectionsExt.unmodifiableOrCopy(components);
dim = new UnitDimension(components);
if (!Units.initialized) {

if (dim == null) {
  components.replaceAll((c, power) -> power.unique());
  components = CollectionsExt.unmodifiableOrCopy(components);
  dim = new UnitDimension(components);
  if (!Units.initialized) {

if (state == COMPLETABLE) {
  if (useSet) {
    target = CollectionsExt.unmodifiableOrCopy((Set<E>) target);
  } else {
    target = CollectionsExt.unmodifiableOrCopy((List<E>) target);

/**
 * Stores the given result in the cache.
 * This method shall be invoked only when {@link #getSearchDomain()} is not {@link Domain#DECLARATION}.
 */
@Override
final Set<IdentifiedObject> cache(final IdentifiedObject object, Set<IdentifiedObject> result) {
  final Map<IdentifiedObject,FindEntry> findPool = ((ConcurrentAuthorityFactory<?>) factory).findPool;
  result = CollectionsExt.unmodifiableOrCopy(result);
  FindEntry entry = new FindEntry();
  synchronized (findPool) {
    final FindEntry c = JDK8.putIfAbsent(findPool, object, entry);
    if (c != null) {
      entry = c;          // May happen if the same set has been computed in another thread.
    }
    // 'finder' should never be null since this method is not invoked directly by this Finder.
    result = entry.set(finder.isIgnoringAxes(), result, object == searching);
  }
  return result;
}

  entry.setValue(clone(entry.getValue()));
return CollectionsExt.unmodifiableOrCopy(map);