/*
* Copyright (C) 2009 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.checkNotNull;
import com.google.common.collect.Lists;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.RandomAccess;
import javax.annotation.Nullable;
/**
* GWT emulated version of {@link ImmutableList}.
* TODO(cpovirk): more doc
*
* @author Hayward Chan
*/
@SuppressWarnings("serial") // we're overriding default serialization
public abstract class ImmutableList<E> extends ImmutableCollection<E>
implements List<E>, RandomAccess {
ImmutableList() {}
// 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;
}
public static <E> ImmutableList<E> of(E element) {
return new SingletonImmutableList<E>(element);
}
public static <E> ImmutableList<E> of(E e1, E e2) {
return new RegularImmutableList<E>(
ImmutableList.<E>nullCheckedList(e1, e2));
}
public static <E> ImmutableList<E> of(E e1, E e2, E e3) {
return new RegularImmutableList<E>(
ImmutableList.<E>nullCheckedList(e1, e2, e3));
}
public static <E> ImmutableList<E> of(E e1, E e2, E e3, E e4) {
return new RegularImmutableList<E>(
ImmutableList.<E>nullCheckedList(e1, e2, e3, e4));
}
public static <E> ImmutableList<E> of(E e1, E e2, E e3, E e4, E e5) {
return new RegularImmutableList<E>(
ImmutableList.<E>nullCheckedList(e1, e2, e3, e4, e5));
}
public static <E> ImmutableList<E> of(E e1, E e2, E e3, E e4, E e5, E e6) {
return new RegularImmutableList<E>(
ImmutableList.<E>nullCheckedList(e1, e2, e3, e4, e5, e6));
}
public static <E> ImmutableList<E> of(
E e1, E e2, E e3, E e4, E e5, E e6, E e7) {
return new RegularImmutableList<E>(
ImmutableList.<E>nullCheckedList(e1, e2, e3, e4, e5, e6, e7));
}
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>(
ImmutableList.<E>nullCheckedList(e1, e2, e3, e4, e5, e6, e7, e8));
}
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>(
ImmutableList.<E>nullCheckedList(e1, e2, e3, e4, e5, e6, e7, e8, e9));
}
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>(ImmutableList.<E>nullCheckedList(
e1, e2, e3, e4, e5, e6, e7, e8, e9, e10));
}
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>(ImmutableList.<E>nullCheckedList(
e1, e2, e3, e4, e5, e6, e7, e8, e9, e10, e11));
}
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) {
final int paramCount = 12;
Object[] array = new Object[paramCount + others.length];
arrayCopy(array, 0, e1, e2, e3, e4, e5, e6, e7, e8, e9, e10, e11, e12);
arrayCopy(array, paramCount, others);
return new RegularImmutableList<E>(ImmutableList.<E>nullCheckedList(array));
}
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>(
ImmutableList.<E>nullCheckedList(elements));
}
}
private static void arrayCopy(Object[] dest, int pos, Object... source) {
System.arraycopy(source, 0, dest, pos, source.length);
}
public static <E> ImmutableList<E> copyOf(Iterable<? extends E> elements) {
checkNotNull(elements); // for GWT
return (elements instanceof Collection)
? copyOf((Collection<? extends E>) elements)
: copyOf(elements.iterator());
}
public static <E> ImmutableList<E> copyOf(Iterator<? extends E> elements) {
return copyFromCollection(Lists.newArrayList(elements));
}
public static <E> ImmutableList<E> copyOf(Collection<? extends E> elements) {
if (elements instanceof ImmutableCollection) {
/*
* 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
ImmutableCollection<E> list = (ImmutableCollection<E>) elements;
return list.asList();
}
return copyFromCollection(elements);
}
public static <E> ImmutableList<E> copyOf(E[] elements) {
checkNotNull(elements); // eager for GWT
return copyOf(Arrays.asList(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>(ImmutableList.<E>nullCheckedList(elements));
}
}
// Factory method that skips the null checks. Used only when the elements
// are guaranteed to be non-null.
static <E> ImmutableList<E> unsafeDelegateList(List<? extends E> list) {
switch (list.size()) {
case 0:
return of();
case 1:
return new SingletonImmutableList<E>(list.iterator().next());
default:
@SuppressWarnings("unchecked")
List<E> castedList = (List<E>) list;
return new RegularImmutableList<E>(castedList);
}
}
/**
* Views the array as an immutable list. The array must have only {@code E} elements.
*
* <p>The array must be internally created.
*/
@SuppressWarnings("unchecked") // caller is reponsible for getting this right
static <E> ImmutableList<E> asImmutableList(Object[] elements) {
return unsafeDelegateList((List) Arrays.asList(elements));
}
private static <E> List<E> nullCheckedList(Object... array) {
for (int i = 0, len = array.length; i < len; i++) {
if (array[i] == null) {
throw new NullPointerException("at index " + i);
}
}
@SuppressWarnings("unchecked")
E[] castedArray = (E[]) array;
return Arrays.asList(castedArray);
}
@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);
}
public final boolean addAll(int index, Collection<? extends E> newElements) {
throw new UnsupportedOperationException();
}
public final E set(int index, E element) {
throw new UnsupportedOperationException();
}
public final void add(int index, E element) {
throw new UnsupportedOperationException();
}
public final E remove(int index) {
throw new UnsupportedOperationException();
}
@Override public UnmodifiableIterator<E> iterator() {
return listIterator();
}
@Override public ImmutableList<E> subList(int fromIndex, int toIndex) {
return unsafeDelegateList(Lists.subListImpl(this, fromIndex, toIndex));
}
@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 ImmutableList<E> asList() {
return this;
}
public ImmutableList<E> reverse() {
List<E> list = Lists.newArrayList(this);
Collections.reverse(list);
return unsafeDelegateList(list);
}
public static <E> Builder<E> builder() {
return new Builder<E>();
}
public static final class Builder<E> extends ImmutableCollection.Builder<E> {
private final ArrayList<E> contents = Lists.newArrayList();
public Builder() {}
@Override public Builder<E> add(E element) {
contents.add(checkNotNull(element));
return this;
}
@Override public Builder<E> addAll(Iterable<? extends E> elements) {
super.addAll(elements);
return this;
}
@Override public Builder<E> add(E... elements) {
checkNotNull(elements); // for GWT
super.add(elements);
return this;
}
@Override public Builder<E> addAll(Iterator<? extends E> elements) {
super.addAll(elements);
return this;
}
@Override public ImmutableList<E> build() {
return copyOf(contents);
}
}
}