8187443: Forest Consolidation: Move files to unified layout

Reviewed-by: darcy, ihse

src/java.base/share/classes/java/util/Enumeration.java

@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 1994, 2015, 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;
+
+/**
+ * An object that implements the Enumeration interface generates a
+ * series of elements, one at a time. Successive calls to the
+ * {@code nextElement} method return successive elements of the
+ * series.
+ * <p>
+ * For example, to print all elements of a {@code Vector<E>} <i>v</i>:
+ * <pre>
+ *   for (Enumeration&lt;E&gt; e = v.elements(); e.hasMoreElements();)
+ *       System.out.println(e.nextElement());</pre>
+ * <p>
+ * Methods are provided to enumerate through the elements of a
+ * vector, the keys of a hashtable, and the values in a hashtable.
+ * Enumerations are also used to specify the input streams to a
+ * {@code SequenceInputStream}.
+ *
+ * @apiNote
+ * The functionality of this interface is duplicated by the {@link Iterator}
+ * interface.  In addition, {@code Iterator} adds an optional remove operation,
+ * and has shorter method names.  New implementations should consider using
+ * {@code Iterator} in preference to {@code Enumeration}. It is possible to
+ * adapt an {@code Enumeration} to an {@code Iterator} by using the
+ * {@link #asIterator} method.
+ *
+ * @see     java.util.Iterator
+ * @see     java.io.SequenceInputStream
+ * @see     java.util.Enumeration#nextElement()
+ * @see     java.util.Hashtable
+ * @see     java.util.Hashtable#elements()
+ * @see     java.util.Hashtable#keys()
+ * @see     java.util.Vector
+ * @see     java.util.Vector#elements()
+ *
+ * @author  Lee Boynton
+ * @since   1.0
+ */
+public interface Enumeration<E> {
+    /**
+     * Tests if this enumeration contains more elements.
+     *
+     * @return  {@code true} if and only if this enumeration object
+     *           contains at least one more element to provide;
+     *          {@code false} otherwise.
+     */
+    boolean hasMoreElements();
+
+    /**
+     * Returns the next element of this enumeration if this enumeration
+     * object has at least one more element to provide.
+     *
+     * @return     the next element of this enumeration.
+     * @exception  NoSuchElementException  if no more elements exist.
+     */
+    E nextElement();
+
+    /**
+     * Returns an {@link Iterator} that traverses the remaining elements
+     * covered by this enumeration. Traversal is undefined if any methods
+     * are called on this enumeration after the call to {@code asIterator}.
+     *
+     * @apiNote
+     * This method is intended to help adapt code that produces
+     * {@code Enumeration} instances to code that consumes {@code Iterator}
+     * instances. For example, the {@link java.util.jar.JarFile#entries
+     * JarFile.entries()} method returns an {@code Enumeration<JarEntry>}.
+     * This can be turned into an {@code Iterator}, and then the
+     * {@code forEachRemaining()} method can be used:
+     *
+     * <pre>{@code
+     *     JarFile jarFile = ... ;
+     *     jarFile.entries().asIterator().forEachRemaining(entry -> { ... });
+     * }</pre>
+     *
+     * (Note that there is also a {@link java.util.jar.JarFile#stream
+     * JarFile.stream()} method that returns a {@code Stream} of entries,
+     * which may be more convenient in some cases.)
+     *
+     * @implSpec
+     * The default implementation returns an {@code Iterator} whose
+     * {@link Iterator#hasNext hasNext} method calls this Enumeration's
+     * {@code hasMoreElements} method, whose {@link Iterator#next next}
+     * method calls this Enumeration's {@code nextElement} method, and
+     * whose {@link Iterator#remove remove} method throws
+     * {@code UnsupportedOperationException}.
+     *
+     * @return an Iterator representing the remaining elements of this Enumeration
+     *
+     * @since 9
+     */
+    default Iterator<E> asIterator() {
+        return new Iterator<>() {
+            @Override public boolean hasNext() {
+                return hasMoreElements();
+            }
+            @Override public E next() {
+                return nextElement();
+            }
+        };
+    }
+}