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FileTreeIterator.java
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124 lines (113 loc) · 3.17 KB
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/*
* Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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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.
*
* <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 {@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();
}
}