Java File Base Name Get baseName(String fn)

Description

Given a full or partial path name, locate the "base name" from the name.

License

Open Source License

Parameter

Parameter	Description
fn	the String filename to scan

Return

the base name element of the string. If the path name does not include a basename element (for example, consists only of a directory specification) then an empty string is returned.

Declaration

public static String baseName(String fn)

Method Source Code

//package com.java2s;
/*//from  w  ww  . ja  va2s.com
 * THIS SOURCE FILE IS PART OF JBASIC, AN OPEN SOURCE PUBLICLY AVAILABLE
 * JAVA SOFTWARE PACKAGE HOSTED BY SOURCEFORGE.NET
 *
 * THIS SOFTWARE IS PROVIDED VIA THE GNU PUBLIC LICENSE AND IS FREELY
 * AVAILABLE FOR ANY PURPOSE COMMERCIAL OR OTHERWISE AS LONG AS THE AUTHORSHIP
 * AND COPYRIGHT INFORMATION IS RETAINED INTACT AND APPROPRIATELY VISIBLE
 * TO THE END USER.
 * 
 * SEE THE PROJECT FILE AT HTTP://WWW.SOURCEFORGE.NET/PROJECTS/JBASIC FOR
 * MORE INFORMATION.
 * 
 * COPYRIGHT 2003-2011 BY TOM COLE, TOMCOLE@USERS.SF.NET
 *
 * Created on Jun 23, 2007 by tom
 *
 */

public class Main {
    /**
     * Given a full or partial path name, locate the "base name" from
     * the name.  This means removing all absolute or relative path 
     * name prefixes and any extension suffix.
     * @param fn the String filename to scan
     * @return the base name element of the string.  If the path name
     * does not include a basename element (for example, consists only of a
     * directory specification) then an empty string is returned.
     */
    public static String baseName(String fn) {

        /*
         * Start at the end of the string and search for a path
         * separator character.
         */

        String separator = System.getProperty("file.separator");

        int sepLen = separator.length();
        int startPos = fn.length() - sepLen;
        if (startPos < 0)
            return "";

        int pos;
        for (pos = startPos; pos >= 0; pos--) {
            String testChar = fn.substring(pos, pos + sepLen);
            if (testChar.equals(separator))
                break;
            if (testChar.equals(":"))
                break;
        }

        if (pos == startPos)
            return "";

        /*
         * Make a new copy of the part of the string that has only
         * the filename.  If we never found a separator, adjust to 
         * the start of the string. If we did find a separator, then
         * don't include it in the new filename string.
         */

        if (pos < 0)
            pos = 0;
        else
            pos += 1;

        String fileName = fn.substring(pos);

        /*
         * Strip off the last part of the filename (the "extension")
         * if there is one, identified by the "dot".
         */

        for (pos = fileName.length() - 1; pos >= 0; pos--)
            if (fileName.charAt(pos) == '.')
                break;
        if (pos < 0)
            pos = fileName.length();

        return fileName.substring(0, pos);
    }
}