How to use

nonNull

method

in

org.apache.sis.internal.util.CollectionsExt

/**
 * Returns identifiers which references elsewhere the object's defining information.
 * Alternatively identifiers by which this object can be referenced.
 *
 * @return this object identifiers, or an empty set if there is none.
 *
 * @see IdentifiedObjects#getIdentifier(IdentifiedObject, Citation)
 */
@Override
public Set<ReferenceIdentifier> getIdentifiers() {
  return nonNull(identifiers);    // Needs to be null-safe because we may have a null value on unmarshalling.
}

/**
 * Returns identifiers which references elsewhere the object's defining information.
 * Alternatively identifiers by which this object can be referenced.
 *
 * @return this object identifiers, or an empty set if there is none.
 *
 * @see IdentifiedObjects#getIdentifier(IdentifiedObject, Citation)
 */
@Override
public Set<ReferenceIdentifier> getIdentifiers() {
  return nonNull(identifiers);    // Needs to be null-safe because we may have a null value on unmarshalling.
}

/**
 * Returns alternative names by which this object is identified.
 *
 * @return the aliases, or an empty collection if there is none.
 *
 * @see #getName()
 */
@Override
public Collection<GenericName> getAlias() {
  return nonNull(alias);          // Needs to be null-safe because we may have a null value on unmarshalling.
}

/**
 * Returns alternative names by which this object is identified.
 *
 * @return the aliases, or an empty collection if there is none.
 *
 * @see #getName()
 */
@Override
public Collection<GenericName> getAlias() {
  return nonNull(alias);          // Needs to be null-safe because we may have a null value on unmarshalling.
}

/**
 * Returns an estimation of the impact of this operation on point accuracy.
 * The positional accuracy gives position error estimates for target coordinates
 * of this coordinate operation, assuming no errors in source coordinates.
 *
 * @return the position error estimations, or an empty collection if not available.
 *
 * @see #getLinearAccuracy()
 */
@Override
public Collection<PositionalAccuracy> getCoordinateOperationAccuracy() {
  return CollectionsExt.nonNull(coordinateOperationAccuracy);
}

/**
 * Returns an estimation of the impact of this operation on point accuracy.
 * The positional accuracy gives position error estimates for target coordinates
 * of this coordinate operation, assuming no errors in source coordinates.
 *
 * @return the position error estimations, or an empty collection if not available.
 *
 * @see #getLinearAccuracy()
 */
@Override
public Collection<PositionalAccuracy> getCoordinateOperationAccuracy() {
  return CollectionsExt.nonNull(coordinateOperationAccuracy);
}

/**
 * Invoked by {@link #hashCode()} for computing the hash code when first needed.
 * This method is invoked at most once in normal execution, or an arbitrary amount of times if Java
 * assertions are enabled. The hash code value shall never change during the whole lifetime of this
 * object in a JVM. The hash code value does not need to be the same in two different executions of
 * the JVM.
 *
 * <div class="section">Overriding</div>
 * Subclasses can override this method for using more properties in hash code calculation.
 * All {@code computeHashCode()} methods shall invoke {@code super.computeHashCode()},
 * <strong>not</strong> {@code hashCode()}. Example:
 *
 * {@preformat java
 *     &#64;Override
 *     protected long computeHashCode() {
 *         return super.computeHashCode() + 31 * Objects.hash(myProperties);
 *     }
 * }
 *
 * @return the hash code value. This value may change in any future Apache SIS version.
 */
protected long computeHashCode() {
  return Objects.hash(name, nonNull(alias), nonNull(identifiers), remarks) ^ getInterface().hashCode();
}

/**
 * Invoked by {@link #hashCode()} for computing the hash code when first needed.
 * This method is invoked at most once in normal execution, or an arbitrary amount of times if Java
 * assertions are enabled. The hash code value shall never change during the whole lifetime of this
 * object in a JVM. The hash code value does not need to be the same in two different executions of
 * the JVM.
 *
 * <div class="section">Overriding</div>
 * Subclasses can override this method for using more properties in hash code calculation.
 * All {@code computeHashCode()} methods shall invoke {@code super.computeHashCode()},
 * <strong>not</strong> {@code hashCode()}. Example:
 *
 * {@preformat java
 *     &#64;Override
 *     protected long computeHashCode() {
 *         return super.computeHashCode() + 31 * Objects.hash(myProperties);
 *     }
 * }
 *
 * @return the hash code value. This value may change in any future Apache SIS version.
 */
protected long computeHashCode() {
  return Objects.hash(name, nonNull(alias), nonNull(identifiers), remarks) ^ getInterface().hashCode();
}

/**
 * Returns an enumeration of valid values for the attribute, or an empty array if none.
 * This convenience method returns the value of the characteristic set by {@link #setValidValues(Object...)}.
 *
 * @return valid values for the attribute, or an empty array if none.
 */
@SuppressWarnings("unchecked")
public V[] getValidValues() {
  final Collection<?> c = CollectionsExt.nonNull((Collection<?>)
      getCharacteristic(AttributeConvention.VALID_VALUES_CHARACTERISTIC));
  final V[] values = (V[]) Array.newInstance(valueClass, c.size());
  int index = 0;
  for (final Object value : c) {
    values[index++] = (V) value;        // ArrayStoreException if 'value' is not the expected type.
  }
  return values;
}

/**
 * Returns an enumeration of valid values for the attribute, or an empty array if none.
 * This convenience method returns the value of the characteristic set by {@link #setValidValues(Object...)}.
 *
 * @return valid values for the attribute, or an empty array if none.
 */
@SuppressWarnings("unchecked")
public V[] getValidValues() {
  final Collection<?> c = CollectionsExt.nonNull((Collection<?>)
      getCharacteristic(AttributeConvention.VALID_VALUES_CHARACTERISTIC));
  final V[] values = (V[]) Array.newInstance(valueClass, c.size());
  int index = 0;
  for (final Object value : c) {
    values[index++] = (V) value;        // ArrayStoreException if 'value' is not the expected type.
  }
  return values;
}

nonNull(alias).equals(nonNull(that.alias)) &&
nonNull(identifiers).equals(nonNull(that.identifiers)) &&
Objects.equals(remarks, that.remarks);

nonNull(alias).equals(nonNull(that.alias)) &&
nonNull(identifiers).equals(nonNull(that.identifiers)) &&
Objects.equals(remarks, that.remarks);

  return (MemberName) id;
for (final GenericName alias : nonNull(parameter.getAlias())) {
  if (alias instanceof MemberName) {
    return (MemberName) alias;

  return (MemberName) id;
for (final GenericName alias : nonNull(parameter.getAlias())) {
  if (alias instanceof MemberName) {
    return (MemberName) alias;