platform/sensinact-security/sensinact-security-none/src/test/java/org/eclipse/sensinact/gateway/core/security/test/FilesEnumerator.java

/*
* Copyright (c) 2020 Kentyou.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
*    Kentyou - initial API and implementation
 */
package org.eclipse.sensinact.gateway.core.security.test;

import java.io.File;
import java.util.Enumeration;
import java.util.Stack;

public class FilesEnumerator implements Enumeration<File> {
	Stack<Enumeration<File>> stack = null;

	public FilesEnumerator(File sourceDirectory) {
		stack = new Stack<Enumeration<File>>();
		stack.push(newEnumeration(sourceDirectory));
	}

	@Override
	public boolean hasMoreElements() {
		if (stack.isEmpty()) {
			return false;
		}
		Enumeration<File> current = null;
		while (!stack.isEmpty() && !(current = stack.pop()).hasMoreElements()) {
			current = null;
		}
		if (current != null) {
			stack.push(current);
			return true;
		}
		return false;
	}

	@Override
	public File nextElement() {
		if (stack.isEmpty()) {
			return null;
		}
		Enumeration<File> current = stack.pop();
		File file = current.nextElement();
		stack.push(current);
		if (file.isDirectory()) {
			stack.push(newEnumeration(file));
		}
		return file;
	}

	private static Enumeration<File> newEnumeration(final File file) {
		return new Enumeration<File>() {
			int position = 0;
			File[] files = file.isDirectory() ? file.listFiles() : new File[] { file };

			@Override
			public boolean hasMoreElements() {
				return position < files.length;
			}

			@Override
			public File nextElement() {
				if (hasMoreElements()) {
					return files[position++];
				}
				return null;
			}
		};
	}
}