Java Path Relative Get getRelativePath(File ref_file, File tst

Description

get Relative Path

License

Open Source License

Declaration

public static String getRelativePath(File ref_file, File tst_file)

Method Source Code

//package com.java2s;
/*//from  w  w w .ja v a 2s .c o m
 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

import java.io.File;

import java.io.IOException;

import java.util.Vector;

public class Main {
    private static File[] fileSysRoots;
    private static boolean fileSysRootsGot = false;

    /**
     * Constructs 'relative' path for given two paths. For example, for
     * "/aaa/bbb/ccc/ddd" and "/aaa/xxx/yyy" relative path would be
     * "../../../xxx/yyy". NOTE: this code is probably system dependent
     *
     * @param ref_path reference path
     * @param tst_path path to construct relative form for
     * @return constructed relative path
     */
    public static String getRelativePath(String ref_path, String tst_path) {
        String[] ref_arr = split(ref_path, File.separatorChar);
        String[] tst_arr = split(tst_path, File.separatorChar);
        int last_match_ind = -1;
        String res = "";

        for (int i = 0; i < ref_arr.length && i < tst_arr.length; i++) {
            if (!ref_arr[i].equals(tst_arr[i])) {
                break;
            }
            last_match_ind = i;
        }
        for (int i = 0; i < ref_arr.length - last_match_ind - 1; i++) {
            res += ".." + File.separator;
        }
        for (int i = last_match_ind + 1; i < tst_arr.length; i++) {
            res += tst_arr[i] + File.separator;
        }
        if (res.equals("")) {
            res = "." + File.separator;
        }
        return res.substring(0, res.length() - 1);
    }

    public static String getRelativePath(File ref_file, File tst_file) {
        File[] roots = getFileSystemRoots();
        String ref_path = null;
        String tst_path = null;

        try {
            ref_path = ref_file.getCanonicalPath();
            tst_path = tst_file.getCanonicalPath();
        } catch (IOException e) {
            ref_path = ref_file.getAbsolutePath();
            tst_path = tst_file.getAbsolutePath();
        }
        if (roots != null) {
            for (int i = 0; i < roots.length; i++) {
                String root = roots[i].getAbsolutePath();
                if (ref_path.startsWith(root) != tst_path.startsWith(root)) {
                    return null;
                }
            }
        }
        return getRelativePath(ref_path, tst_path);
    }

    public static String[] split(String s, char delim) {
        String str = s;
        if (str == null) {
            return null;
        }
        Vector v = new Vector();
        for (int ind = str.indexOf(delim); ind >= 0; ind = str.indexOf(delim)) {
            if (ind > 0) {
                v.addElement(str.substring(0, ind));
            }
            str = str.substring(ind + 1);
        }
        if (str.length() > 0) {
            v.addElement(str);
        }
        String[] res = new String[v.size()];
        v.copyInto(res);
        return res;
    }

    private static File[] getFileSystemRoots() {
        if (!fileSysRootsGot) {
            fileSysRoots = File.listRoots();
            fileSysRootsGot = true;
        }
        return fileSysRoots;
    }
}

Java Path Relative Get getRelativePath(File ref_file, File tst_file)

Description

License

Declaration

Method Source Code

Related