Utils.java

/*
 * Copyright (C) 2011 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.exoplatform.portal.mop.user;

/**
 * A set of utils for this package.
 *
 * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
 */
class Utils {

    /**
     * Parse the path with the following algorithm:
     *
     * <ul>
     * <li>The one char <code>/</code> string returns the null array</li>
     * <li>Any leading <code>/<code> char is ommited</li>
     * <li>Any trailing </code>/</code> chars are ommited</li>
     * <li>All the substrings obtained by slicing the remaining string by the <code>/</code> char are returned as an array, even
     * the empty strings</li>
     * </ul>
     *
     * <p>
     * Note that this is a reimplementation of a previous method that was using regex splitting, this reimplementation was done
     * in order to minimize the created object count in mind and attempt to create the minimum required.
     * </p>
     *
     * @param path the path
     * @return the parse result
     * @throws NullPointerException if the path argument is null
     */
    static String[] parsePath(String path) throws NullPointerException {
        // Where we start
        final int start = 0 < path.length() && path.charAt(0) == '/' ? 1 : 0;

        //
        if (start == path.length()) {
            return null;
        }

        // Where we end
        int end = path.length();
        while (end > start && path.charAt(end - 1) == '/') {
            end--;
        }

        // Count the number of slash
        int count = 0;
        int i = start;
        while (true) {
            int pos = path.indexOf('/', i);
            if (pos == -1) {
                pos = end;
            }
            if (pos == end) {
                if (pos > i) {
                    count++;
                }
                break;
            } else {
                count++;
                i = pos + 1;
            }
        }

        // Now fill the array
        String[] names = new String[count];
        i = start;
        int index = 0;
        while (true) {
            int pos = path.indexOf('/', i);
            if (pos == -1) {
                pos = end;
            }
            if (pos == end) {
                if (pos > i) {
                    names[index] = path.substring(i, end);
                }
                break;
            } else {
                if (i < pos) {
                    names[index++] = path.substring(i, pos);
                } else {
                    names[index++] = "";
                }
                i = pos + 1;
            }
        }

        //
        return names;
    }
}