How to use

CheckedArrayList

in

org.apache.sis.internal.util

/**
 * Creates a new association of the given role.
 *
 * @param role Information about the association.
 */
public MultiValuedAssociation(final DefaultAssociationRole role) {
  super(role);
  values = new CheckedArrayList<>(AbstractFeature.class);
}

/**
 * Returns the given collection as a {@code CheckedArrayList} instance of the given element type.
 *
 * @param  <E>         the element type.
 * @param  collection  the collection or {@code null}.
 * @param  type        the element type.
 * @return the given collection as a {@code CheckedArrayList}, or {@code null} if the given collection was null.
 * @throws ClassCastException if an element is not of the expected type.
 *
 * @since 0.5
 */
@SuppressWarnings("unchecked")
public static <E> CheckedArrayList<E> castOrCopy(final Collection<?> collection, final Class<E> type) {
  if (collection == null) {
    return null;
  }
  if (collection instanceof CheckedArrayList<?> && ((CheckedArrayList<?>) collection).type == type) {
    return (CheckedArrayList<E>) collection;
  } else {
    final CheckedArrayList<E> list = new CheckedArrayList<>(type, collection.size());
    list.addAll((Collection) collection);               // addAll will perform the type checks.
    return list;
  }
}

/**
 * Creates a collection which will initially contain only the given value.
 * At the difference of {@link Collections#singletonList(Object)}, this method returns a modifiable list.
 */
@SuppressWarnings("unchecked")
private static <V> Collection<V> singletonList(final Class<V> valueClass, final int minimumOccurs, final Object value) {
  final CheckedArrayList<V> values = new CheckedArrayList<>(valueClass, Math.max(minimumOccurs, 4));
  values.add((V) value);                              // Type will be checked by CheckedArrayList.
  return values;
}

/**
 * Sets the attribute value.
 *
 * @param  value  the new value, or {@code null} for removing all values from this attribute.
 */
@Override
public void setValue(final V value) {
  values.clear();
  if (value != null) {
    values.add(value);
  }
}

/**
 * Creates a new association of the given role initialized to the given values.
 *
 * @param role   Information about the association.
 * @param values The initial values, or {@code null} for initializing to an empty list.
 */
MultiValuedAssociation(final DefaultAssociationRole role, final Object values) {
  super(role);
  if (values == null) {
    this.values = new CheckedArrayList<>(AbstractFeature.class);
  } else {
    this.values = CheckedArrayList.castOrCopy((CheckedArrayList<?>) values, AbstractFeature.class);
  }
}

/**
 * Tests {@link CheckedArrayList#addAll(Collection)}.
 */
@Test
public void testAddAll() {
  final CheckedArrayList<String> list = new CheckedArrayList<>(String.class);
  assertTrue(list.add("One"));
  assertTrue(list.addAll(Arrays.asList("Two", "Three")));
  assertEquals(Arrays.asList("One", "Two", "Three"), list);
}

/**
 * Ensures that we can not element of the wrong type in a sublist.
 */
@Test
@DependsOnMethod("testAddWrongType")
public void testAddWrongTypeToSublist() {
  final CheckedArrayList<String> list = new CheckedArrayList<>(String.class);
  assertTrue(list.add("One"));
  assertTrue(list.add("Two"));
  assertTrue(list.add("Three"));
  testAddWrongType(list.subList(1, 3));
  // Exception message is JDK-dependent, so we can not test it.
}

/**
 * Returns the feature, or {@code null} if none.
 *
 * @return the feature (may be {@code null}).
 * @throws IllegalStateException if this association contains more than one value.
 */
@Override
public AbstractFeature getValue() {
  switch (values.size()) {
    case 0:  return null;
    case 1:  return values.get(0);
    default: throw new IllegalStateException(Resources.format(Resources.Keys.NotASingleton_1, getName()));
  }
}

/**
 * Sets the attribute values. All previous values are replaced by the given collection.
 *
 * @param  newValues  the new values.
 */
@Override
public void setValues(final Collection<? extends V> newValues) {
  if (newValues != values) {
    ArgumentChecks.ensureNonNull("values", newValues);      // The parameter name in public API is "values".
    values.clear();
    values.addAll(newValues);
  }
}

/**
 * Replaces the element at the specified position in this list with the specified element.
 *
 * @param  index    index of element to replace.
 * @param  element  element to be stored at the specified position.
 * @return the element previously at the specified position.
 * @throws IndexOutOfBoundsException if index out of range.
 * @throws NullPointerException if the given element is {@code null}.
 * @throws ClassCastException if the given element is not of the expected type.
 */
@Override
public E set(final int index, final E element) {
  if (ensureValid(element)) {
    return super.set(index, element);
  }
  return get(index);
}

/**
 * Verifies the validity of the given attribute value, and returns the value to store in the feature.
 * An attribute:
 * <ul>
 *   <li>May be a singleton,  in which case the value class is verified.</li>
 *   <li>May be a collection, in which case the class each elements in the collection is verified.</li>
 * </ul>
 *
 * @param  value  the value, which shall be non-null.
 */
private static <T> Object verifyAttributeValue(final DefaultAttributeType<T> type, final Object value) {
  final Class<T> valueClass = type.getValueClass();
  final boolean isSingleton = Field.isSingleton(type.getMaximumOccurs());
  if (valueClass.isInstance(value)) {
    return isSingleton ? value : singletonList(valueClass, type.getMinimumOccurs(), value);
  } else if (!isSingleton && value instanceof Collection<?>) {
    return CheckedArrayList.castOrCopy((Collection<?>) value, valueClass);
  } else {
    throw new ClassCastException(illegalValueClass(type, valueClass, value));
  }
}

  /**
   * Tests {@link CheckedArrayList#castOrCopy(Collection, Class)}.
   */
  @Test
  @DependsOnMethod("testAddAll")
  public void testCastOrCopy() {
    assertNull(CheckedArrayList.castOrCopy(null, String.class));
    final List<String> fruits = Arrays.asList("Apple", "Orange", "Raisin");
    final CheckedArrayList<String> asStrings = CheckedArrayList.castOrCopy(fruits, String.class);
    assertEquals ("Should have the given element type.", String.class, asStrings.getElementType());
    assertNotSame("Should have created a new instance.", fruits, asStrings);
    assertEquals ("Should contain the same data.",       fruits, asStrings);
    assertSame   ("Should cast existing instance.", asStrings, CheckedArrayList.castOrCopy(asStrings, String.class));

    final CheckedArrayList<CharSequence> asChars = CheckedArrayList.castOrCopy(asStrings, CharSequence.class);
    assertEquals ("Should have the given element type.", CharSequence.class, asChars.getElementType());
    assertNotSame("Should have created a new instance.", asStrings, asChars);
    assertEquals ("Should contain the same data.",       asStrings, asChars);
    assertEquals ("Should contain the same data.",       fruits,    asChars);

    try {
      CheckedArrayList.castOrCopy(asChars, Integer.class);
      fail("Should not be allowed to cast String to Integer.");
    } catch (ClassCastException e) {
      final String message = e.getMessage();
      assertTrue(message, message.contains("String"));
      assertTrue(message, message.contains("Integer"));
    }
  }
}

/**
 * Returns a copy of this association.
 * This implementation returns a <em>shallow</em> copy:
 * the association {@linkplain #getValues() values} are <strong>not</strong> cloned.
 *
 * @return a clone of this association.
 * @throws CloneNotSupportedException if this association can not be cloned.
 */
@Override
@SuppressWarnings("unchecked")
public MultiValuedAssociation clone() throws CloneNotSupportedException {
  final MultiValuedAssociation clone = (MultiValuedAssociation) super.clone();
  clone.values = (CheckedArrayList<AbstractFeature>) clone.values.clone();
  return clone;
}

/**
 * Creates a new association of the given role initialized to the given values.
 *
 * @param role   Information about the association.
 * @param values The initial values, or {@code null} for initializing to an empty list.
 */
MultiValuedAssociation(final DefaultAssociationRole role, final Object values) {
  super(role);
  if (values == null) {
    this.values = new CheckedArrayList<>(AbstractFeature.class);
  } else {
    this.values = CheckedArrayList.castOrCopy((CheckedArrayList<?>) values, AbstractFeature.class);
  }
}

/**
 * Sets the attribute value.
 *
 * @param  value  the new value, or {@code null} for removing all values from this attribute.
 */
@Override
public void setValue(final V value) {
  values.clear();
  if (value != null) {
    values.add(value);
  }
}

/**
 * Returns the attribute value, or {@code null} if none.
 *
 * @return the attribute value (may be {@code null}).
 * @throws IllegalStateException if this attribute contains more than one value.
 */
@Override
public V getValue() {
  switch (values.size()) {
    case 0:  return null;
    case 1:  return values.get(0);
    default: throw new IllegalStateException(Resources.format(Resources.Keys.NotASingleton_1, getName()));
  }
}

/**
 * Sets the attribute values. All previous values are replaced by the given collection.
 *
 * @param  newValues  the new values.
 */
@Override
public void setValues(final Collection<? extends V> newValues) {
  if (newValues != values) {
    ArgumentChecks.ensureNonNull("values", newValues);      // The parameter name in public API is "values".
    values.clear();
    values.addAll(newValues);
  }
}

/**
 * Replaces the element at the specified position in this list with the specified element.
 *
 * @param  index    index of element to replace.
 * @param  element  element to be stored at the specified position.
 * @return the element previously at the specified position.
 * @throws IndexOutOfBoundsException if index out of range.
 * @throws NullPointerException if the given element is {@code null}.
 * @throws ClassCastException if the given element is not of the expected type.
 */
@Override
public E set(final int index, final E element) {
  if (ensureValid(element)) {
    return super.set(index, element);
  }
  return get(index);
}

/**
 * Verifies the validity of the given attribute value, and returns the value to store in the feature.
 * An attribute:
 * <ul>
 *   <li>May be a singleton,  in which case the value class is verified.</li>
 *   <li>May be a collection, in which case the class each elements in the collection is verified.</li>
 * </ul>
 *
 * @param  value  the value, which shall be non-null.
 */
private static <T> Object verifyAttributeValue(final DefaultAttributeType<T> type, final Object value) {
  final Class<T> valueClass = type.getValueClass();
  final boolean isSingleton = Field.isSingleton(type.getMaximumOccurs());
  if (valueClass.isInstance(value)) {
    return isSingleton ? value : singletonList(valueClass, type.getMinimumOccurs(), value);
  } else if (!isSingleton && value instanceof Collection<?>) {
    return CheckedArrayList.castOrCopy((Collection<?>) value, valueClass);
  } else {
    throw new ClassCastException(illegalValueClass(type, valueClass, value));
  }
}

/**
 * Returns a copy of this association.
 * This implementation returns a <em>shallow</em> copy:
 * the association {@linkplain #getValues() values} are <strong>not</strong> cloned.
 *
 * @return a clone of this association.
 * @throws CloneNotSupportedException if this association can not be cloned.
 */
@Override
@SuppressWarnings("unchecked")
public MultiValuedAssociation clone() throws CloneNotSupportedException {
  final MultiValuedAssociation clone = (MultiValuedAssociation) super.clone();
  clone.values = (CheckedArrayList<AbstractFeature>) clone.values.clone();
  return clone;
}