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.Arrays; 32 import java.util.Iterator; 33 import java.util.NoSuchElementException; 34 import java.util.Objects; 35 import java.nio.file.FileTreeWalker.Event; 36 import java.util.function.Consumer; 37 38 /** 39 * An {@code Iterator to iterate over the nodes of a file tree. 40 * 41 * <pre>{@code 42 * try (FileTreeIterator iterator = new FileTreeIterator(start, maxDepth, options)) { 43 * while (iterator.hasNext()) { 44 * Event ev = iterator.next(); 45 * Path path = ev.file(); 46 * BasicFileAttributes attrs = ev.attributes(); 47 * } 48 * } 49 * }</pre> 50 */ 51 52 class FileTreeIterator implements Iterator<Event>, Closeable { 53 private final Consumer<IOException> ioExceptionHandler; 54 private final FileTreeWalker walker; 55 private Event next; 56 57 /** 58 * Creates a new iterator to walk the file tree starting at the given file. 59 * 60 * @throws IllegalArgumentException 61 * if {@code maxDepth} is negative 62 * @throws SecurityException 63 * if the security manager denies access to the starting file 64 * @throws NullPointerException 65 * if {@code start} or {@code options} or {@code ioExceptionHandler} 66 * is {@code null} or the options array contains a {@code null} element 67 */ 68 FileTreeIterator(Path start, int maxDepth, 69 Consumer<IOException> ioExceptionHandler, 70 FileVisitOption... options) 71 { 72 this.ioExceptionHandler = Objects.requireNonNull(ioExceptionHandler); 73 this.walker = new FileTreeWalker(Arrays.asList(options), maxDepth); 74 this.next = walker.walk(start); 75 assert next.type() == FileTreeWalker.EventType.ENTRY || 76 next.type() == FileTreeWalker.EventType.START_DIRECTORY; 77 78 // handle IOException if there a problem accessing the starting file 79 IOException ioe = next.ioeException(); 80 if (ioe != null) { 81 next = null; 82 try { 83 ioExceptionHandler.accept(ioe); 84 } catch (Throwable t) { 85 // clean-up when constructors throws 86 try { 87 close(); 88 } catch (Throwable ct) { 89 t.addSuppressed(ct); 90 } 91 throw t; 92 } 93 } 94 } 95 96 private void fetchNextIfNeeded() { 97 if (next == null) { 98 FileTreeWalker.Event ev = walker.next(); 99 while (ev != null) { 100 IOException ioe = ev.ioeException(); 101 if (ioe != null) { 102 ioExceptionHandler.accept(ioe); 103 } 104 // END_DIRECTORY events are ignored 105 else if (ev.type() != FileTreeWalker.EventType.END_DIRECTORY) { 106 next = ev; 107 return; 108 } 109 ev = walker.next(); 110 } 111 } 112 } 113 114 @Override 115 public boolean hasNext() { 116 if (!walker.isOpen()) 117 throw new IllegalStateException(); 118 fetchNextIfNeeded(); 119 return next != null; 120 } 121 122 @Override 123 public Event next() { 124 if (!walker.isOpen()) 125 throw new IllegalStateException(); 126 fetchNextIfNeeded(); 127 if (next == null) 128 throw new NoSuchElementException(); 129 Event result = next; 130 next = null; 131 return result; 132 } 133 134 @Override 135 public void close() { 136 walker.close(); 137 } 138 }