Java Path Relative Get getRelativePath(File fromFile, File toFile)

Description

Calculates the relative path between two files.

License

Apache License

Parameter

Parameter	Description
fromFile	the <code>File</code> to calculate the path from
toFile	the <code>File</code> to calculate the path to

Exception

Parameter	Description
Exception	for undocumented reasons

Return

the relative path between the files

Declaration

public static String getRelativePath(File fromFile, File toFile) throws Exception

Method Source Code


//package com.java2s;
/*//from  w w  w. j  a  v a  2s  . c om
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You 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.
 *
 */

import java.io.File;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;

public class Main {
    /**
     * Calculates the relative path between two files.
     * <p>
     * Implementation note:<br/> This function may throw an IOException if an I/O error occurs
     * because its use of the canonical pathname may require filesystem queries.
     * </p>
     *
     * @param fromFile the <code>File</code> to calculate the path from
     * @param toFile   the <code>File</code> to calculate the path to
     * @return the relative path between the files
     * @throws Exception for undocumented reasons
     * @see File#getCanonicalPath()
     * @since Ant 1.7
     */
    public static String getRelativePath(File fromFile, File toFile) throws Exception {
        String fromPath = fromFile.getCanonicalPath();
        String toPath = toFile.getCanonicalPath();

        // build the path stack info to compare
        String[] fromPathStack = getPathStack(fromPath);
        String[] toPathStack = getPathStack(toPath);

        if (0 < toPathStack.length && 0 < fromPathStack.length) {
            if (!fromPathStack[0].equals(toPathStack[0])) {
                // not the same device (would be "" on Linux/Unix)

                return getPath(Arrays.asList(toPathStack));
            }
        } else {
            // no comparison possible
            return getPath(Arrays.asList(toPathStack));
        }

        int minLength = Math.min(fromPathStack.length, toPathStack.length);
        int same = 1; // Used outside the for loop

        // get index of parts which are equal
        for (; same < minLength && fromPathStack[same].equals(toPathStack[same]); same++) {
            // Do nothing
        }

        List relativePathStack = new ArrayList();

        // if "from" part is longer, fill it up with ".."
        // to reach path which is equal to both paths
        for (int i = same; i < fromPathStack.length; i++) {
            relativePathStack.add("..");
        }

        // fill it up path with parts which were not equal
        for (int i = same; i < toPathStack.length; i++) {
            relativePathStack.add(toPathStack[i]);
        }

        return getPath(relativePathStack);
    }

    /**
     * Gets all names of the path as an array of <code>String</code>s.
     *
     * @param path to get names from
     * @return <code>String</code>s, never <code>null</code>
     * @since Ant 1.7
     */
    public static String[] getPathStack(String path) {
        String normalizedPath = path.replace(File.separatorChar, '/');

        return normalizedPath.split("/");
    }

    /**
     * Gets path from a <code>List</code> of <code>String</code>s.
     *
     * @param pathStack <code>List</code> of <code>String</code>s to be concatenated as a path.
     * @return <code>String</code>, never <code>null</code>
     * @since Ant 1.7
     */
    public static String getPath(List pathStack) {
        // can safely use '/' because Windows understands '/' as separator
        return getPath(pathStack, '/');
    }

    /**
     * Gets path from a <code>List</code> of <code>String</code>s.
     *
     * @param pathStack     <code>List</code> of <code>String</code>s to be concated as a path.
     * @param separatorChar <code>char</code> to be used as separator between names in path
     * @return <code>String</code>, never <code>null</code>
     * @since Ant 1.7
     */
    public static String getPath(final List pathStack, final char separatorChar) {
        final StringBuffer buffer = new StringBuffer();

        final Iterator iter = pathStack.iterator();
        if (iter.hasNext()) {
            buffer.append(iter.next());
        }
        while (iter.hasNext()) {
            buffer.append(separatorChar);
            buffer.append(iter.next());
        }
        return buffer.toString();
    }
}

Java Path Relative Get getRelativePath(File fromFile, File toFile)

Description

License

Parameter

Exception

Return

Declaration

Method Source Code

Related