| /* |
| * Copyright (C) 2007 The Guava Authors |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.google.common.collect; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| import static com.google.common.base.Preconditions.checkElementIndex; |
| import static com.google.common.base.Preconditions.checkNotNull; |
| import static com.google.common.base.Preconditions.checkPositionIndexes; |
| import static com.google.common.collect.CollectPreconditions.checkNonnegative; |
| import static com.google.common.collect.ObjectArrays.checkElementsNotNull; |
| import static com.google.common.collect.RegularImmutableList.EMPTY; |
| |
| import com.google.common.annotations.Beta; |
| import com.google.common.annotations.GwtCompatible; |
| import com.google.common.annotations.VisibleForTesting; |
| import com.google.errorprone.annotations.CanIgnoreReturnValue; |
| import java.io.InvalidObjectException; |
| import java.io.ObjectInputStream; |
| import java.io.Serializable; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Comparator; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.RandomAccess; |
| import java.util.Spliterator; |
| import java.util.function.Consumer; |
| import java.util.function.UnaryOperator; |
| import java.util.stream.Collector; |
| import org.checkerframework.checker.nullness.qual.Nullable; |
| |
| /** |
| * A {@link List} whose contents will never change, with many other important properties detailed at |
| * {@link ImmutableCollection}. |
| * |
| * <p>See the Guava User Guide article on <a href= |
| * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained"> immutable collections</a>. |
| * |
| * @see ImmutableMap |
| * @see ImmutableSet |
| * @author Kevin Bourrillion |
| * @since 2.0 |
| */ |
| @GwtCompatible(serializable = true, emulated = true) |
| @SuppressWarnings("serial") // we're overriding default serialization |
| public abstract class ImmutableList<E> extends ImmutableCollection<E> |
| implements List<E>, RandomAccess { |
| |
| /** |
| * Returns a {@code Collector} that accumulates the input elements into a new {@code |
| * ImmutableList}, in encounter order. |
| * |
| * @since 21.0 |
| */ |
| public static <E> Collector<E, ?, ImmutableList<E>> toImmutableList() { |
| return CollectCollectors.toImmutableList(); |
| } |
| |
| /** |
| * Returns the empty immutable list. This list behaves and performs comparably to {@link |
| * Collections#emptyList}, and is preferable mainly for consistency and maintainability of your |
| * code. |
| */ |
| // Casting to any type is safe because the list will never hold any elements. |
| @SuppressWarnings("unchecked") |
| public static <E> ImmutableList<E> of() { |
| return (ImmutableList<E>) EMPTY; |
| } |
| |
| /** |
| * Returns an immutable list containing a single element. This list behaves and performs |
| * comparably to {@link Collections#singletonList}, but will not accept a null element. It is |
| * preferable mainly for consistency and maintainability of your code. |
| * |
| * @throws NullPointerException if {@code element} is null |
| */ |
| public static <E> ImmutableList<E> of(E element) { |
| return new SingletonImmutableList<E>(element); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * @throws NullPointerException if any element is null |
| */ |
| public static <E> ImmutableList<E> of(E e1, E e2) { |
| return construct(e1, e2); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * @throws NullPointerException if any element is null |
| */ |
| public static <E> ImmutableList<E> of(E e1, E e2, E e3) { |
| return construct(e1, e2, e3); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * @throws NullPointerException if any element is null |
| */ |
| public static <E> ImmutableList<E> of(E e1, E e2, E e3, E e4) { |
| return construct(e1, e2, e3, e4); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * @throws NullPointerException if any element is null |
| */ |
| public static <E> ImmutableList<E> of(E e1, E e2, E e3, E e4, E e5) { |
| return construct(e1, e2, e3, e4, e5); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * @throws NullPointerException if any element is null |
| */ |
| public static <E> ImmutableList<E> of(E e1, E e2, E e3, E e4, E e5, E e6) { |
| return construct(e1, e2, e3, e4, e5, e6); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * @throws NullPointerException if any element is null |
| */ |
| public static <E> ImmutableList<E> of(E e1, E e2, E e3, E e4, E e5, E e6, E e7) { |
| return construct(e1, e2, e3, e4, e5, e6, e7); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * @throws NullPointerException if any element is null |
| */ |
| public static <E> ImmutableList<E> of(E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8) { |
| return construct(e1, e2, e3, e4, e5, e6, e7, e8); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * @throws NullPointerException if any element is null |
| */ |
| public static <E> ImmutableList<E> of(E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8, E e9) { |
| return construct(e1, e2, e3, e4, e5, e6, e7, e8, e9); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * @throws NullPointerException if any element is null |
| */ |
| public static <E> ImmutableList<E> of( |
| E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8, E e9, E e10) { |
| return construct(e1, e2, e3, e4, e5, e6, e7, e8, e9, e10); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * @throws NullPointerException if any element is null |
| */ |
| public static <E> ImmutableList<E> of( |
| E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8, E e9, E e10, E e11) { |
| return construct(e1, e2, e3, e4, e5, e6, e7, e8, e9, e10, e11); |
| } |
| |
| // These go up to eleven. After that, you just get the varargs form, and |
| // whatever warnings might come along with it. :( |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * <p>The array {@code others} must not be longer than {@code Integer.MAX_VALUE - 12}. |
| * |
| * @throws NullPointerException if any element is null |
| * @since 3.0 (source-compatible since 2.0) |
| */ |
| @SafeVarargs // For Eclipse. For internal javac we have disabled this pointless type of warning. |
| public static <E> ImmutableList<E> of( |
| E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8, E e9, E e10, E e11, E e12, E... others) { |
| checkArgument( |
| others.length <= Integer.MAX_VALUE - 12, "the total number of elements must fit in an int"); |
| Object[] array = new Object[12 + others.length]; |
| array[0] = e1; |
| array[1] = e2; |
| array[2] = e3; |
| array[3] = e4; |
| array[4] = e5; |
| array[5] = e6; |
| array[6] = e7; |
| array[7] = e8; |
| array[8] = e9; |
| array[9] = e10; |
| array[10] = e11; |
| array[11] = e12; |
| System.arraycopy(others, 0, array, 12, others.length); |
| return construct(array); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. If {@code elements} is a |
| * {@link Collection}, this method behaves exactly as {@link #copyOf(Collection)}; otherwise, it |
| * behaves exactly as {@code copyOf(elements.iterator()}. |
| * |
| * @throws NullPointerException if {@code elements} contains a null element |
| */ |
| public static <E> ImmutableList<E> copyOf(Iterable<? extends E> elements) { |
| checkNotNull(elements); // TODO(kevinb): is this here only for GWT? |
| return (elements instanceof Collection) |
| ? copyOf((Collection<? extends E>) elements) |
| : copyOf(elements.iterator()); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * <p>Despite the method name, this method attempts to avoid actually copying the data when it is |
| * safe to do so. The exact circumstances under which a copy will or will not be performed are |
| * undocumented and subject to change. |
| * |
| * <p>Note that if {@code list} is a {@code List<String>}, then {@code ImmutableList.copyOf(list)} |
| * returns an {@code ImmutableList<String>} containing each of the strings in {@code list}, while |
| * ImmutableList.of(list)} returns an {@code ImmutableList<List<String>>} containing one element |
| * (the given list itself). |
| * |
| * <p>This method is safe to use even when {@code elements} is a synchronized or concurrent |
| * collection that is currently being modified by another thread. |
| * |
| * @throws NullPointerException if {@code elements} contains a null element |
| */ |
| public static <E> ImmutableList<E> copyOf(Collection<? extends E> elements) { |
| if (elements instanceof ImmutableCollection) { |
| @SuppressWarnings("unchecked") // all supported methods are covariant |
| ImmutableList<E> list = ((ImmutableCollection<E>) elements).asList(); |
| return list.isPartialView() ? ImmutableList.<E>asImmutableList(list.toArray()) : list; |
| } |
| return construct(elements.toArray()); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * @throws NullPointerException if {@code elements} contains a null element |
| */ |
| public static <E> ImmutableList<E> copyOf(Iterator<? extends E> elements) { |
| // We special-case for 0 or 1 elements, but going further is madness. |
| if (!elements.hasNext()) { |
| return of(); |
| } |
| E first = elements.next(); |
| if (!elements.hasNext()) { |
| return of(first); |
| } else { |
| return new ImmutableList.Builder<E>().add(first).addAll(elements).build(); |
| } |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * @throws NullPointerException if {@code elements} contains a null element |
| * @since 3.0 |
| */ |
| public static <E> ImmutableList<E> copyOf(E[] elements) { |
| switch (elements.length) { |
| case 0: |
| return of(); |
| case 1: |
| return of(elements[0]); |
| default: |
| return construct(elements.clone()); |
| } |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, sorted according to their natural |
| * order. The sorting algorithm used is stable, so elements that compare as equal will stay in the |
| * order in which they appear in the input. |
| * |
| * <p>If your data has no duplicates, or you wish to deduplicate elements, use {@code |
| * ImmutableSortedSet.copyOf(elements)}; if you want a {@code List} you can use its {@code |
| * asList()} view. |
| * |
| * <p><b>Java 8 users:</b> If you want to convert a {@link java.util.stream.Stream} to a sorted |
| * {@code ImmutableList}, use {@code stream.sorted().collect(toImmutableList())}. |
| * |
| * @throws NullPointerException if any element in the input is null |
| * @since 21.0 |
| */ |
| public static <E extends Comparable<? super E>> ImmutableList<E> sortedCopyOf( |
| Iterable<? extends E> elements) { |
| Comparable<?>[] array = Iterables.toArray(elements, new Comparable<?>[0]); |
| checkElementsNotNull((Object[]) array); |
| Arrays.sort(array); |
| return asImmutableList(array); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in sorted order relative to the |
| * specified comparator. The sorting algorithm used is stable, so elements that compare as equal |
| * will stay in the order in which they appear in the input. |
| * |
| * <p>If your data has no duplicates, or you wish to deduplicate elements, use {@code |
| * ImmutableSortedSet.copyOf(comparator, elements)}; if you want a {@code List} you can use its |
| * {@code asList()} view. |
| * |
| * <p><b>Java 8 users:</b> If you want to convert a {@link java.util.stream.Stream} to a sorted |
| * {@code ImmutableList}, use {@code stream.sorted(comparator).collect(toImmutableList())}. |
| * |
| * @throws NullPointerException if any element in the input is null |
| * @since 21.0 |
| */ |
| public static <E> ImmutableList<E> sortedCopyOf( |
| Comparator<? super E> comparator, Iterable<? extends E> elements) { |
| checkNotNull(comparator); |
| @SuppressWarnings("unchecked") // all supported methods are covariant |
| E[] array = (E[]) Iterables.toArray(elements); |
| checkElementsNotNull(array); |
| Arrays.sort(array, comparator); |
| return asImmutableList(array); |
| } |
| |
| /** Views the array as an immutable list. Checks for nulls; does not copy. */ |
| private static <E> ImmutableList<E> construct(Object... elements) { |
| return asImmutableList(checkElementsNotNull(elements)); |
| } |
| |
| /** |
| * Views the array as an immutable list. Does not check for nulls; does not copy. |
| * |
| * <p>The array must be internally created. |
| */ |
| static <E> ImmutableList<E> asImmutableList(Object[] elements) { |
| return asImmutableList(elements, elements.length); |
| } |
| |
| /** |
| * Views the array as an immutable list. Copies if the specified range does not cover the complete |
| * array. Does not check for nulls. |
| */ |
| static <E> ImmutableList<E> asImmutableList(Object[] elements, int length) { |
| switch (length) { |
| case 0: |
| return of(); |
| case 1: |
| return of((E) elements[0]); |
| default: |
| if (length < elements.length) { |
| elements = Arrays.copyOf(elements, length); |
| } |
| return new RegularImmutableList<E>(elements); |
| } |
| } |
| |
| ImmutableList() {} |
| |
| // This declaration is needed to make List.iterator() and |
| // ImmutableCollection.iterator() consistent. |
| @Override |
| public UnmodifiableIterator<E> iterator() { |
| return listIterator(); |
| } |
| |
| @Override |
| public UnmodifiableListIterator<E> listIterator() { |
| return listIterator(0); |
| } |
| |
| @Override |
| public UnmodifiableListIterator<E> listIterator(int index) { |
| return new AbstractIndexedListIterator<E>(size(), index) { |
| @Override |
| protected E get(int index) { |
| return ImmutableList.this.get(index); |
| } |
| }; |
| } |
| |
| @Override |
| public void forEach(Consumer<? super E> consumer) { |
| checkNotNull(consumer); |
| int n = size(); |
| for (int i = 0; i < n; i++) { |
| consumer.accept(get(i)); |
| } |
| } |
| |
| @Override |
| public int indexOf(@Nullable Object object) { |
| return (object == null) ? -1 : Lists.indexOfImpl(this, object); |
| } |
| |
| @Override |
| public int lastIndexOf(@Nullable Object object) { |
| return (object == null) ? -1 : Lists.lastIndexOfImpl(this, object); |
| } |
| |
| @Override |
| public boolean contains(@Nullable Object object) { |
| return indexOf(object) >= 0; |
| } |
| |
| // constrain the return type to ImmutableList<E> |
| |
| /** |
| * Returns an immutable list of the elements between the specified {@code fromIndex}, inclusive, |
| * and {@code toIndex}, exclusive. (If {@code fromIndex} and {@code toIndex} are equal, the empty |
| * immutable list is returned.) |
| */ |
| @Override |
| public ImmutableList<E> subList(int fromIndex, int toIndex) { |
| checkPositionIndexes(fromIndex, toIndex, size()); |
| int length = toIndex - fromIndex; |
| if (length == size()) { |
| return this; |
| } else if (length == 0) { |
| return of(); |
| } else if (length == 1) { |
| return of(get(fromIndex)); |
| } else { |
| return subListUnchecked(fromIndex, toIndex); |
| } |
| } |
| |
| /** |
| * Called by the default implementation of {@link #subList} when {@code toIndex - fromIndex > 1}, |
| * after index validation has already been performed. |
| */ |
| ImmutableList<E> subListUnchecked(int fromIndex, int toIndex) { |
| return new SubList(fromIndex, toIndex - fromIndex); |
| } |
| |
| class SubList extends ImmutableList<E> { |
| final transient int offset; |
| final transient int length; |
| |
| SubList(int offset, int length) { |
| this.offset = offset; |
| this.length = length; |
| } |
| |
| @Override |
| public int size() { |
| return length; |
| } |
| |
| @Override |
| public E get(int index) { |
| checkElementIndex(index, length); |
| return ImmutableList.this.get(index + offset); |
| } |
| |
| @Override |
| public ImmutableList<E> subList(int fromIndex, int toIndex) { |
| checkPositionIndexes(fromIndex, toIndex, length); |
| return ImmutableList.this.subList(fromIndex + offset, toIndex + offset); |
| } |
| |
| @Override |
| boolean isPartialView() { |
| return true; |
| } |
| } |
| |
| /** |
| * Guaranteed to throw an exception and leave the list unmodified. |
| * |
| * @throws UnsupportedOperationException always |
| * @deprecated Unsupported operation. |
| */ |
| @CanIgnoreReturnValue |
| @Deprecated |
| @Override |
| public final boolean addAll(int index, Collection<? extends E> newElements) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** |
| * Guaranteed to throw an exception and leave the list unmodified. |
| * |
| * @throws UnsupportedOperationException always |
| * @deprecated Unsupported operation. |
| */ |
| @CanIgnoreReturnValue |
| @Deprecated |
| @Override |
| public final E set(int index, E element) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** |
| * Guaranteed to throw an exception and leave the list unmodified. |
| * |
| * @throws UnsupportedOperationException always |
| * @deprecated Unsupported operation. |
| */ |
| @Deprecated |
| @Override |
| public final void add(int index, E element) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** |
| * Guaranteed to throw an exception and leave the list unmodified. |
| * |
| * @throws UnsupportedOperationException always |
| * @deprecated Unsupported operation. |
| */ |
| @CanIgnoreReturnValue |
| @Deprecated |
| @Override |
| public final E remove(int index) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** |
| * Guaranteed to throw an exception and leave the list unmodified. |
| * |
| * @throws UnsupportedOperationException always |
| * @deprecated Unsupported operation. |
| */ |
| @Deprecated |
| @Override |
| public final void replaceAll(UnaryOperator<E> operator) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** |
| * Guaranteed to throw an exception and leave the list unmodified. |
| * |
| * @throws UnsupportedOperationException always |
| * @deprecated Unsupported operation. |
| */ |
| @Deprecated |
| @Override |
| public final void sort(Comparator<? super E> c) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** |
| * Returns this list instance. |
| * |
| * @since 2.0 |
| */ |
| @Override |
| public final ImmutableList<E> asList() { |
| return this; |
| } |
| |
| @Override |
| public Spliterator<E> spliterator() { |
| return CollectSpliterators.indexed(size(), SPLITERATOR_CHARACTERISTICS, this::get); |
| } |
| |
| @Override |
| int copyIntoArray(Object[] dst, int offset) { |
| // this loop is faster for RandomAccess instances, which ImmutableLists are |
| int size = size(); |
| for (int i = 0; i < size; i++) { |
| dst[offset + i] = get(i); |
| } |
| return offset + size; |
| } |
| |
| /** |
| * Returns a view of this immutable list in reverse order. For example, {@code ImmutableList.of(1, |
| * 2, 3).reverse()} is equivalent to {@code ImmutableList.of(3, 2, 1)}. |
| * |
| * @return a view of this immutable list in reverse order |
| * @since 7.0 |
| */ |
| public ImmutableList<E> reverse() { |
| return (size() <= 1) ? this : new ReverseImmutableList<E>(this); |
| } |
| |
| private static class ReverseImmutableList<E> extends ImmutableList<E> { |
| private final transient ImmutableList<E> forwardList; |
| |
| ReverseImmutableList(ImmutableList<E> backingList) { |
| this.forwardList = backingList; |
| } |
| |
| private int reverseIndex(int index) { |
| return (size() - 1) - index; |
| } |
| |
| private int reversePosition(int index) { |
| return size() - index; |
| } |
| |
| @Override |
| public ImmutableList<E> reverse() { |
| return forwardList; |
| } |
| |
| @Override |
| public boolean contains(@Nullable Object object) { |
| return forwardList.contains(object); |
| } |
| |
| @Override |
| public int indexOf(@Nullable Object object) { |
| int index = forwardList.lastIndexOf(object); |
| return (index >= 0) ? reverseIndex(index) : -1; |
| } |
| |
| @Override |
| public int lastIndexOf(@Nullable Object object) { |
| int index = forwardList.indexOf(object); |
| return (index >= 0) ? reverseIndex(index) : -1; |
| } |
| |
| @Override |
| public ImmutableList<E> subList(int fromIndex, int toIndex) { |
| checkPositionIndexes(fromIndex, toIndex, size()); |
| return forwardList.subList(reversePosition(toIndex), reversePosition(fromIndex)).reverse(); |
| } |
| |
| @Override |
| public E get(int index) { |
| checkElementIndex(index, size()); |
| return forwardList.get(reverseIndex(index)); |
| } |
| |
| @Override |
| public int size() { |
| return forwardList.size(); |
| } |
| |
| @Override |
| boolean isPartialView() { |
| return forwardList.isPartialView(); |
| } |
| } |
| |
| @Override |
| public boolean equals(@Nullable Object obj) { |
| return Lists.equalsImpl(this, obj); |
| } |
| |
| @Override |
| public int hashCode() { |
| int hashCode = 1; |
| int n = size(); |
| for (int i = 0; i < n; i++) { |
| hashCode = 31 * hashCode + get(i).hashCode(); |
| |
| hashCode = ~~hashCode; |
| // needed to deal with GWT integer overflow |
| } |
| return hashCode; |
| } |
| |
| /* |
| * Serializes ImmutableLists as their logical contents. This ensures that |
| * implementation types do not leak into the serialized representation. |
| */ |
| static class SerializedForm implements Serializable { |
| final Object[] elements; |
| |
| SerializedForm(Object[] elements) { |
| this.elements = elements; |
| } |
| |
| Object readResolve() { |
| return copyOf(elements); |
| } |
| |
| private static final long serialVersionUID = 0; |
| } |
| |
| private void readObject(ObjectInputStream stream) throws InvalidObjectException { |
| throw new InvalidObjectException("Use SerializedForm"); |
| } |
| |
| @Override |
| Object writeReplace() { |
| return new SerializedForm(toArray()); |
| } |
| |
| /** |
| * Returns a new builder. The generated builder is equivalent to the builder created by the {@link |
| * Builder} constructor. |
| */ |
| public static <E> Builder<E> builder() { |
| return new Builder<E>(); |
| } |
| |
| /** |
| * Returns a new builder, expecting the specified number of elements to be added. |
| * |
| * <p>If {@code expectedSize} is exactly the number of elements added to the builder before {@link |
| * Builder#build} is called, the builder is likely to perform better than an unsized {@link |
| * #builder()} would have. |
| * |
| * <p>It is not specified if any performance benefits apply if {@code expectedSize} is close to, |
| * but not exactly, the number of elements added to the builder. |
| * |
| * @since 23.1 |
| */ |
| @Beta |
| public static <E> Builder<E> builderWithExpectedSize(int expectedSize) { |
| checkNonnegative(expectedSize, "expectedSize"); |
| return new ImmutableList.Builder<E>(expectedSize); |
| } |
| |
| /** |
| * A builder for creating immutable list instances, especially {@code public static final} lists |
| * ("constant lists"). Example: |
| * |
| * <pre>{@code |
| * public static final ImmutableList<Color> GOOGLE_COLORS |
| * = new ImmutableList.Builder<Color>() |
| * .addAll(WEBSAFE_COLORS) |
| * .add(new Color(0, 191, 255)) |
| * .build(); |
| * }</pre> |
| * |
| * <p>Elements appear in the resulting list in the same order they were added to the builder. |
| * |
| * <p>Builder instances can be reused; it is safe to call {@link #build} multiple times to build |
| * multiple lists in series. Each new list contains all the elements of the ones created before |
| * it. |
| * |
| * @since 2.0 |
| */ |
| public static final class Builder<E> extends ImmutableCollection.Builder<E> { |
| @VisibleForTesting Object[] contents; |
| private int size; |
| private boolean forceCopy; |
| |
| /** |
| * Creates a new builder. The returned builder is equivalent to the builder generated by {@link |
| * ImmutableList#builder}. |
| */ |
| public Builder() { |
| this(DEFAULT_INITIAL_CAPACITY); |
| } |
| |
| Builder(int capacity) { |
| this.contents = new Object[capacity]; |
| this.size = 0; |
| } |
| |
| private void getReadyToExpandTo(int minCapacity) { |
| if (contents.length < minCapacity) { |
| this.contents = Arrays.copyOf(contents, expandedCapacity(contents.length, minCapacity)); |
| forceCopy = false; |
| } else if (forceCopy) { |
| contents = Arrays.copyOf(contents, contents.length); |
| forceCopy = false; |
| } |
| } |
| |
| /** |
| * Adds {@code element} to the {@code ImmutableList}. |
| * |
| * @param element the element to add |
| * @return this {@code Builder} object |
| * @throws NullPointerException if {@code element} is null |
| */ |
| @CanIgnoreReturnValue |
| @Override |
| public Builder<E> add(E element) { |
| checkNotNull(element); |
| getReadyToExpandTo(size + 1); |
| contents[size++] = element; |
| return this; |
| } |
| |
| /** |
| * Adds each element of {@code elements} to the {@code ImmutableList}. |
| * |
| * @param elements the {@code Iterable} to add to the {@code ImmutableList} |
| * @return this {@code Builder} object |
| * @throws NullPointerException if {@code elements} is null or contains a null element |
| */ |
| @CanIgnoreReturnValue |
| @Override |
| public Builder<E> add(E... elements) { |
| checkElementsNotNull(elements); |
| add(elements, elements.length); |
| return this; |
| } |
| |
| private void add(Object[] elements, int n) { |
| getReadyToExpandTo(size + n); |
| System.arraycopy(elements, 0, contents, size, n); |
| size += n; |
| } |
| |
| /** |
| * Adds each element of {@code elements} to the {@code ImmutableList}. |
| * |
| * @param elements the {@code Iterable} to add to the {@code ImmutableList} |
| * @return this {@code Builder} object |
| * @throws NullPointerException if {@code elements} is null or contains a null element |
| */ |
| @CanIgnoreReturnValue |
| @Override |
| public Builder<E> addAll(Iterable<? extends E> elements) { |
| checkNotNull(elements); |
| if (elements instanceof Collection) { |
| Collection<?> collection = (Collection<?>) elements; |
| getReadyToExpandTo(size + collection.size()); |
| if (collection instanceof ImmutableCollection) { |
| ImmutableCollection<?> immutableCollection = (ImmutableCollection<?>) collection; |
| size = immutableCollection.copyIntoArray(contents, size); |
| return this; |
| } |
| } |
| super.addAll(elements); |
| return this; |
| } |
| |
| /** |
| * Adds each element of {@code elements} to the {@code ImmutableList}. |
| * |
| * @param elements the {@code Iterator} to add to the {@code ImmutableList} |
| * @return this {@code Builder} object |
| * @throws NullPointerException if {@code elements} is null or contains a null element |
| */ |
| @CanIgnoreReturnValue |
| @Override |
| public Builder<E> addAll(Iterator<? extends E> elements) { |
| super.addAll(elements); |
| return this; |
| } |
| |
| @CanIgnoreReturnValue |
| Builder<E> combine(Builder<E> builder) { |
| checkNotNull(builder); |
| add(builder.contents, builder.size); |
| return this; |
| } |
| |
| /** |
| * Returns a newly-created {@code ImmutableList} based on the contents of the {@code Builder}. |
| */ |
| @Override |
| public ImmutableList<E> build() { |
| forceCopy = true; |
| return asImmutableList(contents, size); |
| } |
| } |
| } |