| /* |
| * Copyright (C) 2007 Google Inc. |
| * |
| * 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 com.google.common.annotations.GwtCompatible; |
| |
| import java.io.InvalidObjectException; |
| import java.io.ObjectInputStream; |
| import java.io.Serializable; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.RandomAccess; |
| |
| import javax.annotation.Nullable; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| |
| /** |
| * A high-performance, immutable, random-access {@code List} implementation. |
| * Does not permit null elements. |
| * |
| * <p>Unlike {@link Collections#unmodifiableList}, which is a <i>view</i> of a |
| * separate collection that can still change, an instance of {@code |
| * ImmutableList} contains its own private data and will <i>never</i> change. |
| * {@code ImmutableList} is convenient for {@code public static final} lists |
| * ("constant lists") and also lets you easily make a "defensive copy" of a list |
| * provided to your class by a caller. |
| * |
| * <p><b>Note</b>: Although this class is not final, it cannot be subclassed as |
| * it has no public or protected constructors. Thus, instances of this type are |
| * guaranteed to be immutable. |
| * |
| * @see ImmutableMap |
| * @see ImmutableSet |
| * @author Kevin Bourrillion |
| * @since 2010.01.04 <b>stable</b> (imported from Google Collections Library) |
| */ |
| @GwtCompatible(serializable = true) |
| @SuppressWarnings("serial") // we're overriding default serialization |
| public abstract class ImmutableList<E> extends ImmutableCollection<E> |
| implements List<E>, RandomAccess { |
| /** |
| * Returns the empty immutable list. This set 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>) EmptyImmutableList.INSTANCE; |
| } |
| |
| /** |
| * Returns an immutable list containing a single element. This list behaves |
| * and performs comparably to {@link Collections#singleton}, 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); |
| } |
| |
| /** |
| * Identical to {@link #of(Object[])}. |
| * |
| * @throws NullPointerException if any element is null |
| */ |
| public static <E> ImmutableList<E> of(E e1, E e2) { |
| return new RegularImmutableList<E>(copyIntoArray(e1, e2)); |
| } |
| |
| /** |
| * Identical to {@link #of(Object[])}. |
| * |
| * @throws NullPointerException if any element is null |
| */ |
| public static <E> ImmutableList<E> of(E e1, E e2, E e3) { |
| return new RegularImmutableList<E>(copyIntoArray(e1, e2, e3)); |
| } |
| |
| /** |
| * Identical to {@link #of(Object[])}. |
| * |
| * @throws NullPointerException if any element is null |
| */ |
| public static <E> ImmutableList<E> of(E e1, E e2, E e3, E e4) { |
| return new RegularImmutableList<E>(copyIntoArray(e1, e2, e3, e4)); |
| } |
| |
| /** |
| * Identical to {@link #of(Object[])}. |
| * |
| * @throws NullPointerException if any element is null |
| */ |
| public static <E> ImmutableList<E> of(E e1, E e2, E e3, E e4, E e5) { |
| return new RegularImmutableList<E>(copyIntoArray(e1, e2, e3, e4, e5)); |
| } |
| |
| /** |
| * Identical to {@link #of(Object[])}. |
| * |
| * @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 new RegularImmutableList<E>(copyIntoArray(e1, e2, e3, e4, e5, e6)); |
| } |
| |
| /** |
| * Identical to {@link #of(Object[])}. |
| * |
| * @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 new RegularImmutableList<E>( |
| copyIntoArray(e1, e2, e3, e4, e5, e6, e7)); |
| } |
| |
| /** |
| * Identical to {@link #of(Object[])}. |
| * |
| * @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 new RegularImmutableList<E>( |
| copyIntoArray(e1, e2, e3, e4, e5, e6, e7, e8)); |
| } |
| |
| /** |
| * Identical to {@link #of(Object[])}. |
| * |
| * @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 new RegularImmutableList<E>( |
| copyIntoArray(e1, e2, e3, e4, e5, e6, e7, e8, e9)); |
| } |
| |
| /** |
| * Identical to {@link #of(Object[])}. |
| * |
| * @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 new RegularImmutableList<E>( |
| copyIntoArray(e1, e2, e3, e4, e5, e6, e7, e8, e9, e10)); |
| } |
| |
| /** |
| * Identical to {@link #of(Object[])}. |
| * |
| * @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 new RegularImmutableList<E>( |
| copyIntoArray(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. |
| * |
| * @throws NullPointerException if any of {@code elements} is null |
| */ |
| public static <E> ImmutableList<E> of(E... elements) { |
| checkNotNull(elements); // for GWT |
| switch (elements.length) { |
| case 0: |
| return ImmutableList.of(); |
| case 1: |
| return new SingletonImmutableList<E>(elements[0]); |
| default: |
| return new RegularImmutableList<E>(copyIntoArray(elements)); |
| } |
| } |
| |
| /** |
| * 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 any of {@code elements} is null |
| */ |
| @SuppressWarnings("unchecked") // bugs.sun.com/view_bug.do?bug_id=6558557 |
| public static <E> ImmutableList<E> copyOf(Iterable<? extends E> elements) { |
| checkNotNull(elements); |
| return (elements instanceof Collection) |
| ? copyOf((Collection<? extends E>) elements) |
| : copyOf(elements.iterator()); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * <p><b>Note:</b> Despite what the method name suggests, if {@code elements} |
| * is an {@code ImmutableList}, no copy will actually be performed, and the |
| * given list itself will be returned. |
| * |
| * <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 any of {@code elements} is null |
| * @since 2010.01.04 <b>stable</b> (Iterable overload existed previously) |
| */ |
| public static <E> ImmutableList<E> copyOf(Collection<? extends E> elements) { |
| checkNotNull(elements); |
| // TODO: Once the ImmutableAsList and ImmutableSortedAsList are |
| // GWT-compatible, return elements.asList() when elements is an |
| // ImmutableCollection. |
| if (elements instanceof ImmutableList) { |
| /* |
| * TODO: When given an ImmutableList that's a sublist, copy the referenced |
| * portion of the array into a new array to save space? |
| */ |
| @SuppressWarnings("unchecked") // all supported methods are covariant |
| ImmutableList<E> list = (ImmutableList<E>) elements; |
| return list; |
| } |
| return copyFromCollection(elements); |
| } |
| |
| /** |
| * Returns an immutable list containing the given elements, in order. |
| * |
| * @throws NullPointerException if any of {@code elements} is null |
| */ |
| public static <E> ImmutableList<E> copyOf(Iterator<? extends E> elements) { |
| return copyFromCollection(Lists.newArrayList(elements)); |
| } |
| |
| private static <E> ImmutableList<E> copyFromCollection( |
| Collection<? extends E> collection) { |
| Object[] elements = collection.toArray(); |
| switch (elements.length) { |
| case 0: |
| return of(); |
| case 1: |
| @SuppressWarnings("unchecked") // collection had only Es in it |
| ImmutableList<E> list = new SingletonImmutableList<E>((E) elements[0]); |
| return list; |
| default: |
| return new RegularImmutableList<E>(copyIntoArray(elements)); |
| } |
| } |
| |
| ImmutableList() {} |
| |
| // This declaration is needed to make List.iterator() and |
| // ImmutableCollection.iterator() consistent. |
| @Override public abstract UnmodifiableIterator<E> iterator(); |
| |
| // Mark these two methods with @Nullable |
| |
| public abstract int indexOf(@Nullable Object object); |
| |
| public abstract int lastIndexOf(@Nullable Object object); |
| |
| // 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.) |
| */ |
| public abstract ImmutableList<E> subList(int fromIndex, int toIndex); |
| |
| /** |
| * Guaranteed to throw an exception and leave the list unmodified. |
| * |
| * @throws UnsupportedOperationException always |
| */ |
| 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 |
| */ |
| public final E set(int index, E element) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** |
| * Guaranteed to throw an exception and leave the list unmodified. |
| * |
| * @throws UnsupportedOperationException always |
| */ |
| public final void add(int index, E element) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** |
| * Guaranteed to throw an exception and leave the list unmodified. |
| * |
| * @throws UnsupportedOperationException always |
| */ |
| public final E remove(int index) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| private static Object[] copyIntoArray(Object... source) { |
| Object[] array = new Object[source.length]; |
| int index = 0; |
| for (Object element : source) { |
| if (element == null) { |
| throw new NullPointerException("at index " + index); |
| } |
| array[index++] = element; |
| } |
| return array; |
| } |
| |
| /** |
| * Returns this list instance. |
| * |
| * @since 2010.01.04 <b>tentative</b> |
| */ |
| @Override public ImmutableList<E> asList() { |
| return this; |
| } |
| |
| /* |
| * Serializes ImmutableLists as their logical contents. This ensures that |
| * implementation types do not leak into the serialized representation. |
| */ |
| private static class SerializedForm implements Serializable { |
| final Object[] elements; |
| SerializedForm(Object[] elements) { |
| this.elements = elements; |
| } |
| Object readResolve() { |
| return of(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>(); |
| } |
| |
| /** |
| * A builder for creating immutable list instances, especially |
| * {@code public static final} lists ("constant lists"). |
| * |
| * <p>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>Builder instances can be reused - it is safe to call {@link #build} |
| * multiple times to build multiple lists in series. Each new list |
| * contains the one created before it. |
| */ |
| public static final class Builder<E> extends ImmutableCollection.Builder<E> { |
| private final ArrayList<E> contents = Lists.newArrayList(); |
| |
| /** |
| * Creates a new builder. The returned builder is equivalent to the builder |
| * generated by {@link ImmutableList#builder}. |
| */ |
| public Builder() {} |
| |
| /** |
| * 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 |
| */ |
| @Override public Builder<E> add(E element) { |
| contents.add(checkNotNull(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 |
| */ |
| @Override public Builder<E> addAll(Iterable<? extends E> elements) { |
| if (elements instanceof Collection) { |
| Collection<?> collection = (Collection<?>) elements; |
| contents.ensureCapacity(contents.size() + collection.size()); |
| } |
| super.addAll(elements); |
| 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 |
| */ |
| @Override public Builder<E> add(E... elements) { |
| checkNotNull(elements); // for GWT |
| contents.ensureCapacity(contents.size() + elements.length); |
| super.add(elements); |
| 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 |
| */ |
| @Override public Builder<E> addAll(Iterator<? extends E> elements) { |
| super.addAll(elements); |
| return this; |
| } |
| |
| /** |
| * Returns a newly-created {@code ImmutableList} based on the contents of |
| * the {@code Builder}. |
| */ |
| @Override public ImmutableList<E> build() { |
| return copyOf(contents); |
| } |
| } |
| } |