8187443: Forest Consolidation: Move files to unified layout

Reviewed-by: darcy, ihse

src/java.base/share/classes/java/nio/file/FileTreeIterator.java

@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 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.nio.file;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.nio.file.FileTreeWalker.Event;
+
+/**
+ * An {@code Iterator} to iterate over the nodes of a file tree.
+ *
+ * <pre>{@code
+ *     try (FileTreeIterator iterator = new FileTreeIterator(start, maxDepth, options)) {
+ *         while (iterator.hasNext()) {
+ *             Event ev = iterator.next();
+ *             Path path = ev.file();
+ *             BasicFileAttributes attrs = ev.attributes();
+ *         }
+ *     }
+ * }</pre>
+ */
+
+class FileTreeIterator implements Iterator<Event>, Closeable {
+    private final FileTreeWalker walker;
+    private Event next;
+
+    /**
+     * Creates a new iterator to walk the file tree starting at the given file.
+     *
+     * @throws  IllegalArgumentException
+     *          if {@code maxDepth} is negative
+     * @throws  IOException
+     *          if an I/O errors occurs opening the starting file
+     * @throws  SecurityException
+     *          if the security manager denies access to the starting file
+     * @throws  NullPointerException
+     *          if {@code start} or {@code options} is {@code null} or
+     *          the options array contains a {@code null} element
+     */
+    FileTreeIterator(Path start, int maxDepth, FileVisitOption... options)
+        throws IOException
+    {
+        this.walker = new FileTreeWalker(Arrays.asList(options), maxDepth);
+        this.next = walker.walk(start);
+        assert next.type() == FileTreeWalker.EventType.ENTRY ||
+               next.type() == FileTreeWalker.EventType.START_DIRECTORY;
+
+        // IOException if there a problem accessing the starting file
+        IOException ioe = next.ioeException();
+        if (ioe != null)
+            throw ioe;
+    }
+
+    private void fetchNextIfNeeded() {
+        if (next == null) {
+            FileTreeWalker.Event ev = walker.next();
+            while (ev != null) {
+                IOException ioe = ev.ioeException();
+                if (ioe != null)
+                    throw new UncheckedIOException(ioe);
+
+                // END_DIRECTORY events are ignored
+                if (ev.type() != FileTreeWalker.EventType.END_DIRECTORY) {
+                    next = ev;
+                    return;
+                }
+                ev = walker.next();
+            }
+        }
+    }
+
+    @Override
+    public boolean hasNext() {
+        if (!walker.isOpen())
+            throw new IllegalStateException();
+        fetchNextIfNeeded();
+        return next != null;
+    }
+
+    @Override
+    public Event next() {
+        if (!walker.isOpen())
+            throw new IllegalStateException();
+        fetchNextIfNeeded();
+        if (next == null)
+            throw new NoSuchElementException();
+        Event result = next;
+        next = null;
+        return result;
+    }
+
+    @Override
+    public void close() {
+        walker.close();
+    }
+}