eu.infomas.annotation.FileIterator Maven / Gradle / Ivy
/* FileIterator.java
*
* Created: 2011-10-10 (Year-Month-Day)
* Character encoding: UTF-8
*
****************************************** LICENSE *******************************************
*
* Copyright (c) 2011 - 2013 XIAM Solutions B.V. (http://www.xiam.nl)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package eu.infomas.annotation;
import java.io.File;
import java.io.IOException;
import java.util.Deque;
import java.util.LinkedList;
import java.util.NoSuchElementException;
/**
* {@code FileIterator} enables iteration over all files in a directory and all its sub
* directories.
*
* Usage:
*
* FileIterator iter = new FileIterator(new File("./src"));
* File f;
* while ((f = iter.next()) != null) {
* // do something with f
* assert f == iter.getCurrent();
* }
*
*
* @author Ronald K. Muller
* @since annotation-detector 3.0.0
*/
final class FileIterator {
private final Deque stack = new LinkedList();
private int rootCount;
private File current;
/**
* Create a new {@code FileIterator} using the specified 'filesOrDirectories' as root.
*
* If 'filesOrDirectories' contains a file, the iterator just returns that single file.
* If 'filesOrDirectories' contains a directory, all files in that directory
* and its sub directories are returned (depth first).
*
* @param filesOrDirectories Zero or more {@link File} objects, which are iterated
* in the specified order (depth first)
*/
FileIterator(final File... filesOrDirectories) {
addReverse(filesOrDirectories);
rootCount = stack.size();
}
/**
* Return the last returned file or {@code null} if no more files are available.
*
* @see #next()
*/
public File getFile() {
return current;
}
/**
* Return {@code true} if the current file is one of the files originally
* specified as one of the constructor file parameters, i.e. is a root file
* or directory.
*/
public boolean isRootFile() {
if (current == null) {
throw new NoSuchElementException();
}
return stack.size() < rootCount;
}
/**
* Return the next {@link File} object or {@code null} if no more files are
* available.
*
* @see #getFile()
*/
public File next() throws IOException {
if (stack.isEmpty()) {
current = null;
return null;
} else {
current = stack.removeLast();
if (current.isDirectory()) {
if (stack.size() < rootCount) {
rootCount = stack.size();
}
addReverse(current.listFiles());
return next();
} else {
return current;
}
}
}
/**
* Add the specified files in reverse order.
*/
private void addReverse(final File[] files) {
for (int i = files.length - 1; i >= 0; --i) {
stack.add(files[i]);
}
}
}