/* * 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.util.Objects; import java.nio.file.FileTreeWalker.Event; /** * An {@code Iterator to iterate over the nodes of a file tree. * *
{@code
 *     try (FileTreeIterator iterator = new FileTreeIterator(start, maxDepth, options)) {
 *         while (iterator.hasNext()) {
 *             Event ev = iterator.next();
 *             Path path = ev.file();
 *             BasicFileAttributes attrs = ev.attributes();
 *         }
 *     }
 * }
*/ class FileTreeIterator implements Iterator, 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 {@ocde 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(); } }