/*
* Copyright (c) 2015 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.yangtools.util;
import com.google.common.base.Preconditions;
import com.google.common.collect.UnmodifiableIterator;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import javax.annotation.Nonnull;
/**
* Internal array-backed {@link List}. It assumes the array does not contain nulls and it does not get modified
* externally. These assumptions are not checked. It does not allow modification of the underlying array -- thus it
* is very useful for use with {@link ImmutableOffsetMap}.
*
* @param <E> the type of elements in this list
*/
final class ConstantArrayCollection<E> implements Collection<E>, Serializable {
private static final long serialVersionUID = 1L;
private final E[] array;
ConstantArrayCollection(final E[] array) {
this.array = Preconditions.checkNotNull(array);
}
@Override
public int size() {
return array.length;
}
@Override
public boolean isEmpty() {
return array.length == 0;
}
@Override
public boolean contains(final Object o) {
for (Object wlk : array) {
if (o.equals(wlk)) {
return true;
}
}
return false;
}
@Nonnull
@Override
public Iterator<E> iterator() {
return new UnmodifiableIterator<E>() {
private int i = 0;
@Override
public boolean hasNext() {
return i < array.length;
}
@Override
public E next() {
if (i >= array.length) {
throw new NoSuchElementException();
}
return array[i++];
}
};
}
@Nonnull
@Override
public Object[] toArray() {
return array.clone();
}
@Nonnull
@SuppressWarnings("unchecked")
@Override
public <T> T[] toArray(@Nonnull final T[] a) {
if (a.length < array.length) {
return Arrays.copyOf(array, array.length, (Class<T[]>)a.getClass().getComponentType());
}
System.arraycopy(array, 0, a, 0, array.length);
if (a.length > array.length) {
a[array.length] = null;
}
return a;
}
@Override
public boolean add(final E e) {
throw new UnsupportedOperationException();
}
@Override
public boolean remove(final Object o) {
throw new UnsupportedOperationException();
}
@Override
public boolean containsAll(@Nonnull final Collection<?> c) {
for (Object o : c) {
if (!contains(o)) {
return false;
}
}
return true;
}
@Override
public boolean addAll(@Nonnull final Collection<? extends E> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean removeAll(@Nonnull final Collection<?> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean retainAll(@Nonnull final Collection<?> c) {
throw new UnsupportedOperationException();
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
@Override
public int hashCode() {
int result = 1;
for (E e : array) {
result = 31 * result + e.hashCode();
}
return result;
}
@Override
public boolean equals(final Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof ConstantArrayCollection)) {
return false;
}
return Arrays.equals(array, ((ConstantArrayCollection<?>) obj).array);
}
@Override
public String toString() {
if (array.length == 0) {
return "[]";
}
final StringBuilder sb = new StringBuilder("[");
int i = 0;
while (i < array.length - 1) {
sb.append(String.valueOf(array[i++])).append(", ");
}
return sb.append(String.valueOf(array[i])).append(']').toString();
}
}