--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/util/AbstractCollection.java Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,480 @@
+/*
+ * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package java.util;
+
+/**
+ * This class provides a skeletal implementation of the {@code Collection}
+ * interface, to minimize the effort required to implement this interface. <p>
+ *
+ * To implement an unmodifiable collection, the programmer needs only to
+ * extend this class and provide implementations for the {@code iterator} and
+ * {@code size} methods. (The iterator returned by the {@code iterator}
+ * method must implement {@code hasNext} and {@code next}.)<p>
+ *
+ * To implement a modifiable collection, the programmer must additionally
+ * override this class's {@code add} method (which otherwise throws an
+ * {@code UnsupportedOperationException}), and the iterator returned by the
+ * {@code iterator} method must additionally implement its {@code remove}
+ * method.<p>
+ *
+ * The programmer should generally provide a void (no argument) and
+ * {@code Collection} constructor, as per the recommendation in the
+ * {@code Collection} interface specification.<p>
+ *
+ * The documentation for each non-abstract method in this class describes its
+ * implementation in detail. Each of these methods may be overridden if
+ * the collection being implemented admits a more efficient implementation.<p>
+ *
+ * This class is a member of the
+ * <a href="{@docRoot}/java/util/package-summary.html#CollectionsFramework">
+ * Java Collections Framework</a>.
+ *
+ * @author Josh Bloch
+ * @author Neal Gafter
+ * @see Collection
+ * @since 1.2
+ */
+
+public abstract class AbstractCollection<E> implements Collection<E> {
+ /**
+ * Sole constructor. (For invocation by subclass constructors, typically
+ * implicit.)
+ */
+ protected AbstractCollection() {
+ }
+
+ // Query Operations
+
+ /**
+ * Returns an iterator over the elements contained in this collection.
+ *
+ * @return an iterator over the elements contained in this collection
+ */
+ public abstract Iterator<E> iterator();
+
+ public abstract int size();
+
+ /**
+ * {@inheritDoc}
+ *
+ * @implSpec
+ * This implementation returns {@code size() == 0}.
+ */
+ public boolean isEmpty() {
+ return size() == 0;
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ * @implSpec
+ * This implementation iterates over the elements in the collection,
+ * checking each element in turn for equality with the specified element.
+ *
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ */
+ public boolean contains(Object o) {
+ Iterator<E> it = iterator();
+ if (o==null) {
+ while (it.hasNext())
+ if (it.next()==null)
+ return true;
+ } else {
+ while (it.hasNext())
+ if (o.equals(it.next()))
+ return true;
+ }
+ return false;
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ * @implSpec
+ * This implementation returns an array containing all the elements
+ * returned by this collection's iterator, in the same order, stored in
+ * consecutive elements of the array, starting with index {@code 0}.
+ * The length of the returned array is equal to the number of elements
+ * returned by the iterator, even if the size of this collection changes
+ * during iteration, as might happen if the collection permits
+ * concurrent modification during iteration. The {@code size} method is
+ * called only as an optimization hint; the correct result is returned
+ * even if the iterator returns a different number of elements.
+ *
+ * <p>This method is equivalent to:
+ *
+ * <pre> {@code
+ * List<E> list = new ArrayList<E>(size());
+ * for (E e : this)
+ * list.add(e);
+ * return list.toArray();
+ * }</pre>
+ */
+ public Object[] toArray() {
+ // Estimate size of array; be prepared to see more or fewer elements
+ Object[] r = new Object[size()];
+ Iterator<E> it = iterator();
+ for (int i = 0; i < r.length; i++) {
+ if (! it.hasNext()) // fewer elements than expected
+ return Arrays.copyOf(r, i);
+ r[i] = it.next();
+ }
+ return it.hasNext() ? finishToArray(r, it) : r;
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ * @implSpec
+ * This implementation returns an array containing all the elements
+ * returned by this collection's iterator in the same order, stored in
+ * consecutive elements of the array, starting with index {@code 0}.
+ * If the number of elements returned by the iterator is too large to
+ * fit into the specified array, then the elements are returned in a
+ * newly allocated array with length equal to the number of elements
+ * returned by the iterator, even if the size of this collection
+ * changes during iteration, as might happen if the collection permits
+ * concurrent modification during iteration. The {@code size} method is
+ * called only as an optimization hint; the correct result is returned
+ * even if the iterator returns a different number of elements.
+ *
+ * <p>This method is equivalent to:
+ *
+ * <pre> {@code
+ * List<E> list = new ArrayList<E>(size());
+ * for (E e : this)
+ * list.add(e);
+ * return list.toArray(a);
+ * }</pre>
+ *
+ * @throws ArrayStoreException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ */
+ @SuppressWarnings("unchecked")
+ public <T> T[] toArray(T[] a) {
+ // Estimate size of array; be prepared to see more or fewer elements
+ int size = size();
+ T[] r = a.length >= size ? a :
+ (T[])java.lang.reflect.Array
+ .newInstance(a.getClass().getComponentType(), size);
+ Iterator<E> it = iterator();
+
+ for (int i = 0; i < r.length; i++) {
+ if (! it.hasNext()) { // fewer elements than expected
+ if (a == r) {
+ r[i] = null; // null-terminate
+ } else if (a.length < i) {
+ return Arrays.copyOf(r, i);
+ } else {
+ System.arraycopy(r, 0, a, 0, i);
+ if (a.length > i) {
+ a[i] = null;
+ }
+ }
+ return a;
+ }
+ r[i] = (T)it.next();
+ }
+ // more elements than expected
+ return it.hasNext() ? finishToArray(r, it) : r;
+ }
+
+ /**
+ * The maximum size of array to allocate.
+ * Some VMs reserve some header words in an array.
+ * Attempts to allocate larger arrays may result in
+ * OutOfMemoryError: Requested array size exceeds VM limit
+ */
+ private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
+
+ /**
+ * Reallocates the array being used within toArray when the iterator
+ * returned more elements than expected, and finishes filling it from
+ * the iterator.
+ *
+ * @param r the array, replete with previously stored elements
+ * @param it the in-progress iterator over this collection
+ * @return array containing the elements in the given array, plus any
+ * further elements returned by the iterator, trimmed to size
+ */
+ @SuppressWarnings("unchecked")
+ private static <T> T[] finishToArray(T[] r, Iterator<?> it) {
+ int i = r.length;
+ while (it.hasNext()) {
+ int cap = r.length;
+ if (i == cap) {
+ int newCap = cap + (cap >> 1) + 1;
+ // overflow-conscious code
+ if (newCap - MAX_ARRAY_SIZE > 0)
+ newCap = hugeCapacity(cap + 1);
+ r = Arrays.copyOf(r, newCap);
+ }
+ r[i++] = (T)it.next();
+ }
+ // trim if overallocated
+ return (i == r.length) ? r : Arrays.copyOf(r, i);
+ }
+
+ private static int hugeCapacity(int minCapacity) {
+ if (minCapacity < 0) // overflow
+ throw new OutOfMemoryError
+ ("Required array size too large");
+ return (minCapacity > MAX_ARRAY_SIZE) ?
+ Integer.MAX_VALUE :
+ MAX_ARRAY_SIZE;
+ }
+
+ // Modification Operations
+
+ /**
+ * {@inheritDoc}
+ *
+ * @implSpec
+ * This implementation always throws an
+ * {@code UnsupportedOperationException}.
+ *
+ * @throws UnsupportedOperationException {@inheritDoc}
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ * @throws IllegalArgumentException {@inheritDoc}
+ * @throws IllegalStateException {@inheritDoc}
+ */
+ public boolean add(E e) {
+ throw new UnsupportedOperationException();
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ * @implSpec
+ * This implementation iterates over the collection looking for the
+ * specified element. If it finds the element, it removes the element
+ * from the collection using the iterator's remove method.
+ *
+ * <p>Note that this implementation throws an
+ * {@code UnsupportedOperationException} if the iterator returned by this
+ * collection's iterator method does not implement the {@code remove}
+ * method and this collection contains the specified object.
+ *
+ * @throws UnsupportedOperationException {@inheritDoc}
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ */
+ public boolean remove(Object o) {
+ Iterator<E> it = iterator();
+ if (o==null) {
+ while (it.hasNext()) {
+ if (it.next()==null) {
+ it.remove();
+ return true;
+ }
+ }
+ } else {
+ while (it.hasNext()) {
+ if (o.equals(it.next())) {
+ it.remove();
+ return true;
+ }
+ }
+ }
+ return false;
+ }
+
+
+ // Bulk Operations
+
+ /**
+ * {@inheritDoc}
+ *
+ * @implSpec
+ * This implementation iterates over the specified collection,
+ * checking each element returned by the iterator in turn to see
+ * if it's contained in this collection. If all elements are so
+ * contained {@code true} is returned, otherwise {@code false}.
+ *
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ * @see #contains(Object)
+ */
+ public boolean containsAll(Collection<?> c) {
+ for (Object e : c)
+ if (!contains(e))
+ return false;
+ return true;
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ * @implSpec
+ * This implementation iterates over the specified collection, and adds
+ * each object returned by the iterator to this collection, in turn.
+ *
+ * <p>Note that this implementation will throw an
+ * {@code UnsupportedOperationException} unless {@code add} is
+ * overridden (assuming the specified collection is non-empty).
+ *
+ * @throws UnsupportedOperationException {@inheritDoc}
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ * @throws IllegalArgumentException {@inheritDoc}
+ * @throws IllegalStateException {@inheritDoc}
+ *
+ * @see #add(Object)
+ */
+ public boolean addAll(Collection<? extends E> c) {
+ boolean modified = false;
+ for (E e : c)
+ if (add(e))
+ modified = true;
+ return modified;
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ * @implSpec
+ * This implementation iterates over this collection, checking each
+ * element returned by the iterator in turn to see if it's contained
+ * in the specified collection. If it's so contained, it's removed from
+ * this collection with the iterator's {@code remove} method.
+ *
+ * <p>Note that this implementation will throw an
+ * {@code UnsupportedOperationException} if the iterator returned by the
+ * {@code iterator} method does not implement the {@code remove} method
+ * and this collection contains one or more elements in common with the
+ * specified collection.
+ *
+ * @throws UnsupportedOperationException {@inheritDoc}
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ *
+ * @see #remove(Object)
+ * @see #contains(Object)
+ */
+ public boolean removeAll(Collection<?> c) {
+ Objects.requireNonNull(c);
+ boolean modified = false;
+ Iterator<?> it = iterator();
+ while (it.hasNext()) {
+ if (c.contains(it.next())) {
+ it.remove();
+ modified = true;
+ }
+ }
+ return modified;
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ * @implSpec
+ * This implementation iterates over this collection, checking each
+ * element returned by the iterator in turn to see if it's contained
+ * in the specified collection. If it's not so contained, it's removed
+ * from this collection with the iterator's {@code remove} method.
+ *
+ * <p>Note that this implementation will throw an
+ * {@code UnsupportedOperationException} if the iterator returned by the
+ * {@code iterator} method does not implement the {@code remove} method
+ * and this collection contains one or more elements not present in the
+ * specified collection.
+ *
+ * @throws UnsupportedOperationException {@inheritDoc}
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ *
+ * @see #remove(Object)
+ * @see #contains(Object)
+ */
+ public boolean retainAll(Collection<?> c) {
+ Objects.requireNonNull(c);
+ boolean modified = false;
+ Iterator<E> it = iterator();
+ while (it.hasNext()) {
+ if (!c.contains(it.next())) {
+ it.remove();
+ modified = true;
+ }
+ }
+ return modified;
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ * @implSpec
+ * This implementation iterates over this collection, removing each
+ * element using the {@code Iterator.remove} operation. Most
+ * implementations will probably choose to override this method for
+ * efficiency.
+ *
+ * <p>Note that this implementation will throw an
+ * {@code UnsupportedOperationException} if the iterator returned by this
+ * collection's {@code iterator} method does not implement the
+ * {@code remove} method and this collection is non-empty.
+ *
+ * @throws UnsupportedOperationException {@inheritDoc}
+ */
+ public void clear() {
+ Iterator<E> it = iterator();
+ while (it.hasNext()) {
+ it.next();
+ it.remove();
+ }
+ }
+
+
+ // String conversion
+
+ /**
+ * Returns a string representation of this collection. The string
+ * representation consists of a list of the collection's elements in the
+ * order they are returned by its iterator, enclosed in square brackets
+ * ({@code "[]"}). Adjacent elements are separated by the characters
+ * {@code ", "} (comma and space). Elements are converted to strings as
+ * by {@link String#valueOf(Object)}.
+ *
+ * @return a string representation of this collection
+ */
+ public String toString() {
+ Iterator<E> it = iterator();
+ if (! it.hasNext())
+ return "[]";
+
+ StringBuilder sb = new StringBuilder();
+ sb.append('[');
+ for (;;) {
+ E e = it.next();
+ sb.append(e == this ? "(this Collection)" : e);
+ if (! it.hasNext())
+ return sb.append(']').toString();
+ sb.append(',').append(' ');
+ }
+ }
+
+}