com.google.common.collect.RegularImmutableList Maven / Gradle / Ivy
/*
* Copyright (C) 2009 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 com.google.common.base.Preconditions;
import java.util.List;
import java.util.ListIterator;
import java.util.NoSuchElementException;
import javax.annotation.Nullable;
/**
* Implementation of {@link ImmutableList} with one or more elements.
*
* @author Kevin Bourrillion
*/
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
class RegularImmutableList extends ImmutableList {
private final transient int offset;
private final transient int size;
private final transient Object[] array;
RegularImmutableList(Object[] array, int offset, int size) {
this.offset = offset;
this.size = size;
this.array = array;
}
RegularImmutableList(Object[] array) {
this(array, 0, array.length);
}
public int size() {
return size;
}
@Override public boolean isEmpty() {
return false;
}
@Override public boolean contains(Object target) {
return indexOf(target) != -1;
}
// The fake cast to E is safe because the creation methods only allow E's
@SuppressWarnings("unchecked")
@Override public UnmodifiableIterator iterator() {
return (UnmodifiableIterator) Iterators.forArray(array, offset, size);
}
@Override public Object[] toArray() {
Object[] newArray = new Object[size()];
System.arraycopy(array, offset, newArray, 0, size);
return newArray;
}
@Override public T[] toArray(T[] other) {
if (other.length < size) {
other = ObjectArrays.newArray(other, size);
} else if (other.length > size) {
other[size] = null;
}
System.arraycopy(array, offset, other, 0, size);
return other;
}
// The fake cast to E is safe because the creation methods only allow E's
@SuppressWarnings("unchecked")
public E get(int index) {
Preconditions.checkElementIndex(index, size);
return (E) array[index + offset];
}
@Override public int indexOf(Object target) {
if (target != null) {
for (int i = offset; i < offset + size; i++) {
if (array[i].equals(target)) {
return i - offset;
}
}
}
return -1;
}
@Override public int lastIndexOf(Object target) {
if (target != null) {
for (int i = offset + size - 1; i >= offset; i--) {
if (array[i].equals(target)) {
return i - offset;
}
}
}
return -1;
}
@Override public ImmutableList subList(int fromIndex, int toIndex) {
Preconditions.checkPositionIndexes(fromIndex, toIndex, size);
return (fromIndex == toIndex)
? ImmutableList.of()
: new RegularImmutableList(
array, offset + fromIndex, toIndex - fromIndex);
}
public ListIterator listIterator() {
return listIterator(0);
}
public ListIterator listIterator(final int start) {
Preconditions.checkPositionIndex(start, size);
return new ListIterator() {
int index = start;
public boolean hasNext() {
return index < size;
}
public boolean hasPrevious() {
return index > 0;
}
public int nextIndex() {
return index;
}
public int previousIndex() {
return index - 1;
}
public E next() {
E result;
try {
result = get(index);
} catch (IndexOutOfBoundsException rethrown) {
throw new NoSuchElementException();
}
index++;
return result;
}
public E previous() {
E result;
try {
result = get(index - 1);
} catch (IndexOutOfBoundsException rethrown) {
throw new NoSuchElementException();
}
index--;
return result;
}
public void set(E o) {
throw new UnsupportedOperationException();
}
public void add(E o) {
throw new UnsupportedOperationException();
}
public void remove() {
throw new UnsupportedOperationException();
}
};
}
@Override public boolean equals(@Nullable Object object) {
if (object == this) {
return true;
}
if (!(object instanceof List)) {
return false;
}
List that = (List) object;
if (this.size() != that.size()) {
return false;
}
int index = offset;
if (object instanceof RegularImmutableList) {
RegularImmutableList other = (RegularImmutableList) object;
for (int i = other.offset; i < other.offset + other.size; i++) {
if (!array[index++].equals(other.array[i])) {
return false;
}
}
} else {
for (Object element : that) {
if (!array[index++].equals(element)) {
return false;
}
}
}
return true;
}
@Override public int hashCode() {
// not caching hash code since it could change if the elements are mutable
// in a way that modifies their hash codes
int hashCode = 1;
for (int i = offset; i < offset + size; i++) {
hashCode = 31 * hashCode + array[i].hashCode();
}
return hashCode;
}
@Override public String toString() {
StringBuilder sb = new StringBuilder(size() * 16);
sb.append('[').append(array[offset]);
for (int i = offset + 1; i < offset + size; i++) {
sb.append(", ").append(array[i]);
}
return sb.append(']').toString();
}
int offset() {
return offset;
}
Object[] array() {
return array;
}
}