1 /* 2 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.nio.file; 27 28 import java.io.Closeable; 29 import java.io.IOException; 30 import java.io.UncheckedIOException; 31 import java.util.Iterator; 32 import java.util.List; 33 import java.util.NoSuchElementException; 34 import java.nio.file.FileTreeWalker.Event; 35 36 /** 37 * An {@code Iterator to iterate over the nodes of a file tree. 38 * 39 * <pre>{@code 40 * try (FileTreeIterator iterator = new FileTreeIterator(start, maxDepth, options)) { 41 * while (iterator.hasNext()) { 42 * Event ev = iterator.next(); 43 * Path path = ev.file(); 44 * BasicFileAttributes attrs = ev.attributes(); 45 * } 46 * } 47 * }</pre> 48 */ 49 50 class FileTreeIterator implements Iterator<Event>, Closeable { 51 private final FileTreeWalker walker; 52 private Event next; 53 54 /** 55 * Creates a new iterator to walk the file tree starting at the given file. 56 * 57 * @throws IllegalArgumentException 58 * if {@code maxDepth} is negative 59 * @throws IOException 60 * if an I/O errors occurs opening the starting file 61 * @throws SecurityException 62 * if the security manager denies access to the starting file 63 * @throws NullPointerException 64 * if {@code start} or {@code options} is {@code null} or 65 * the options array contains a {@code null} element 66 */ 67 FileTreeIterator(Path start, int maxDepth, FileVisitOption... options) 68 throws IOException 69 { 70 // Since options may be a mutable array, use List.of to copy the array 71 // and prevent TOCTOU. 72 this.walker = new FileTreeWalker(List.of(options), maxDepth); 73 this.next = walker.walk(start); 74 assert next.type() == FileTreeWalker.EventType.ENTRY || 75 next.type() == FileTreeWalker.EventType.START_DIRECTORY; 76 77 // IOException if there a problem accessing the starting file 78 IOException ioe = next.ioeException(); 79 if (ioe != null) 80 throw ioe; 81 } 82 83 private void fetchNextIfNeeded() { 84 if (next == null) { 85 FileTreeWalker.Event ev = walker.next(); 86 while (ev != null) { 87 IOException ioe = ev.ioeException(); 88 if (ioe != null) 89 throw new UncheckedIOException(ioe); 90 91 // END_DIRECTORY events are ignored 92 if (ev.type() != FileTreeWalker.EventType.END_DIRECTORY) { 93 next = ev; 94 return; 95 } 96 ev = walker.next(); 97 } 98 } 99 } 100 101 @Override 102 public boolean hasNext() { 103 if (!walker.isOpen()) 104 throw new IllegalStateException(); 105 fetchNextIfNeeded(); 106 return next != null; 107 } 108 109 @Override 110 public Event next() { 111 if (!walker.isOpen()) 112 throw new IllegalStateException(); 113 fetchNextIfNeeded(); 114 if (next == null) 115 throw new NoSuchElementException(); 116 Event result = next; 117 next = null; 118 return result; 119 } 120 121 @Override 122 public void close() { 123 walker.close(); 124 } 125 }