| /*=============================================================================# |
| # Copyright (c) 2009, 2020 Stephan Wahlbrink and others. |
| # |
| # This program and the accompanying materials are made available under the |
| # terms of the Eclipse Public License 2.0 which is available at |
| # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0 |
| # which is available at https://www.apache.org/licenses/LICENSE-2.0. |
| # |
| # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 |
| # |
| # Contributors: |
| # Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation |
| #=============================================================================*/ |
| |
| package org.eclipse.statet.internal.jcommons.collections; |
| |
| import java.util.Collection; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.ListIterator; |
| import java.util.NoSuchElementException; |
| import java.util.RandomAccess; |
| import java.util.Spliterator; |
| import java.util.Spliterators; |
| |
| import org.eclipse.statet.jcommons.collections.IdentityList; |
| import org.eclipse.statet.jcommons.collections.ImIdentityList; |
| import org.eclipse.statet.jcommons.collections.ImList; |
| import org.eclipse.statet.jcommons.lang.NonNullByDefault; |
| import org.eclipse.statet.jcommons.lang.Nullable; |
| |
| |
| /** |
| * Empty list implementation. |
| * <p> |
| * Comparable to <code>Collections.emptyList()</code>.</p> |
| * |
| * @since de.walware.ecommons.coremisc 1.5 |
| */ |
| @NonNullByDefault |
| public final class ImEmptyIdentityList<E> extends AbstractImList<E> implements ImIdentityList<E>, |
| RandomAccess { |
| |
| |
| @SuppressWarnings("rawtypes") |
| public static final ImEmptyIdentityList INSTANCE= new ImEmptyIdentityList(); |
| |
| |
| private final Object[] array= new Object[0]; |
| |
| private final ListIterator<E> iterator= new AbstractImListIter<>() { |
| |
| @Override |
| public boolean hasNext() { |
| return false; |
| } |
| |
| @Override |
| public int nextIndex() { |
| return 0; |
| } |
| |
| @Override |
| public E next() { |
| throw new NoSuchElementException(); |
| } |
| |
| @Override |
| public boolean hasPrevious() { |
| return false; |
| } |
| |
| @Override |
| public int previousIndex() { |
| return -1; |
| } |
| |
| @Override |
| public E previous() { |
| throw new NoSuchElementException(); |
| } |
| |
| }; |
| |
| |
| public ImEmptyIdentityList() { |
| } |
| |
| |
| @Override |
| public int size() { |
| return 0; |
| } |
| |
| @Override |
| public boolean isEmpty() { |
| return true; |
| } |
| |
| @Override |
| public boolean contains(final @Nullable Object o) { |
| return false; |
| } |
| |
| @Override |
| public boolean containsAll(final Collection<?> c) { |
| return c.isEmpty(); |
| } |
| |
| @Override |
| public E get(final int index) { |
| throw new IndexOutOfBoundsException("index= " + index); //$NON-NLS-1$ |
| } |
| |
| @Override |
| public int indexOf(final @Nullable Object o) { |
| return -1; |
| } |
| |
| @Override |
| public int lastIndexOf(final @Nullable Object o) { |
| return -1; |
| } |
| |
| |
| @Override |
| public Iterator<E> iterator() { |
| return this.iterator; |
| } |
| |
| @Override |
| public ListIterator<E> listIterator() { |
| return this.iterator; |
| } |
| |
| @Override |
| public ListIterator<E> listIterator(final int index) { |
| if (index != 0) { |
| throw new IndexOutOfBoundsException("index= " + index); //$NON-NLS-1$ |
| } |
| return this.iterator; |
| } |
| |
| @Override |
| public Spliterator<E> spliterator() { |
| return Spliterators.emptySpliterator(); |
| } |
| |
| |
| @Override |
| public ImIdentityList<E> subList(final int fromIndex, final int toIndex) { |
| if (fromIndex < 0 || toIndex > 0) { |
| throw new IndexOutOfBoundsException("fromIndex= " + fromIndex + ", toIndex= " + toIndex + ", size= " + 1); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ |
| } |
| if (fromIndex > toIndex) { |
| throw new IllegalArgumentException("fromIndex > toIndex: fromIndex= " + fromIndex + ", toIndex= " + toIndex); //$NON-NLS-1$ //$NON-NLS-2$ |
| } |
| return this; |
| } |
| |
| @Override |
| public Object[] toArray() { |
| return this.array; |
| } |
| |
| @Override |
| @SuppressWarnings("null") |
| public <T> T[] toArray(final T[] dest) { |
| if (dest.length > 0) { |
| dest[0]= null; |
| } |
| return dest; |
| } |
| |
| @Override |
| public void copyTo(final Object[] dest, final int destPos) { |
| } |
| |
| @Override |
| public void copyTo(final int srcPos, final Object[] dest, final int destPos, final int length) { |
| assert (false); |
| } |
| |
| @Override |
| @SuppressWarnings("unchecked") |
| public ImList<E> toImList() { |
| return ImEmptyList.INSTANCE; |
| } |
| |
| @Override |
| public ImIdentityList<E> toImIdentityList() { |
| return this; |
| } |
| |
| |
| @Override |
| public int hashCode() { |
| return 1; |
| } |
| |
| @Override |
| public boolean equals(final @Nullable Object obj) { |
| if (obj == this) { |
| return true; |
| } |
| if (obj instanceof IdentityList) { |
| final List<?> other= (List<?>) obj; |
| return (other.isEmpty()); |
| } |
| return false; |
| } |
| |
| @Override |
| public String toString() { |
| return "[]"; //$NON-NLS-1$ |
| } |
| |
| } |