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/*
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* Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.nio.file;
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import java.io.Closeable;
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import java.io.IOException;
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import java.io.UncheckedIOException;
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import java.util.Arrays;
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import java.util.Iterator;
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import java.util.NoSuchElementException;
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import java.util.Objects;
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import java.nio.file.FileTreeWalker.Event;
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/**
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* An {@code Iterator to iterate over the nodes of a file tree.
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*
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* <pre>{@code
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* try (FileTreeIterator iterator = new FileTreeIterator(start, maxDepth, options)) {
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* while (iterator.hasNext()) {
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* Event ev = iterator.next();
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* Path path = ev.file();
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* BasicFileAttributes attrs = ev.attributes();
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* }
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* }
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* }</pre>
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*/
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class FileTreeIterator implements Iterator<Event>, Closeable {
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private final FileTreeWalker walker;
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private Event next;
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/**
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* Creates a new iterator to walk the file tree starting at the given file.
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*
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* @throws IllegalArgumentException
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* if {@code maxDepth} is negative
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* @throws IOException
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* if an I/O errors occurs opening the starting file
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* @throws SecurityException
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* if the security manager denies access to the starting file
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* @throws NullPointerException
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* if {@code start} or {@code options} is {@ocde null} or
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* the options array contains a {@code null} element
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*/
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FileTreeIterator(Path start, int maxDepth, FileVisitOption... options)
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throws IOException
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{
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this.walker = new FileTreeWalker(Arrays.asList(options), maxDepth);
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this.next = walker.walk(start);
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assert next.type() == FileTreeWalker.EventType.ENTRY ||
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next.type() == FileTreeWalker.EventType.START_DIRECTORY;
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// IOException if there a problem accessing the starting file
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IOException ioe = next.ioeException();
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if (ioe != null)
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throw ioe;
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}
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private void fetchNextIfNeeded() {
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if (next == null) {
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FileTreeWalker.Event ev = walker.next();
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while (ev != null) {
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IOException ioe = ev.ioeException();
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if (ioe != null)
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throw new UncheckedIOException(ioe);
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// END_DIRECTORY events are ignored
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if (ev.type() != FileTreeWalker.EventType.END_DIRECTORY) {
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next = ev;
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return;
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}
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ev = walker.next();
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}
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}
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}
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@Override
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public boolean hasNext() {
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if (!walker.isOpen())
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throw new IllegalStateException();
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fetchNextIfNeeded();
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return next != null;
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}
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@Override
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public Event next() {
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if (!walker.isOpen())
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throw new IllegalStateException();
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fetchNextIfNeeded();
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if (next == null)
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throw new NoSuchElementException();
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Event result = next;
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next = null;
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return result;
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}
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@Override
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public void close() {
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walker.close();
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}
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}
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