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A collection of various utility classes to ease working with strings, files, command lines, XML and more.

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package org.codehaus.plexus.util;

/*
 * Copyright The Codehaus Foundation.
 *
 * Licensed 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.StringTokenizer;

/**
 * Path tool contains static methods to assist in determining path-related information such as relative paths.
 *
 * @author Pete Kazmier
 * @author Vincent Massol
 * @author Vincent Siveton
 * @version $Id$
 */
public class PathTool
{
    /**
     * 

Determines the relative path of a filename from a base directory. This method is useful in building relative * links within pages of a web site. It provides similar functionality to Anakia's $relativePath * context variable. The arguments to this method may contain either forward or backward slashes as file separators. * The relative path returned is formed using forward slashes as it is expected this path is to be used as a link in * a web page (again mimicking Anakia's behavior).

* *

This method is thread-safe.

* *
     * PathTool.getRelativePath( null, null )                                   = ""
     * PathTool.getRelativePath( null, "/usr/local/java/bin" )                  = ""
     * PathTool.getRelativePath( "/usr/local/", null )                          = ""
     * PathTool.getRelativePath( "/usr/local/", "/usr/local/java/bin" )         = ".."
     * PathTool.getRelativePath( "/usr/local/", "/usr/local/java/bin/java.sh" ) = "../.."
     * PathTool.getRelativePath( "/usr/local/java/bin/java.sh", "/usr/local/" ) = ""
     * 
* * @param basedir The base directory. * @param filename The filename that is relative to the base directory. * @return The relative path of the filename from the base directory. This value is not terminated with a forward * slash. A zero-length string is returned if: the filename is not relative to the base directory, * basedir is null or zero-length, or filename is null or zero-length. */ public static final String getRelativePath( String basedir, String filename ) { basedir = uppercaseDrive( basedir ); filename = uppercaseDrive( filename ); /* * Verify the arguments and make sure the filename is relative to the base directory. */ if ( basedir == null || basedir.length() == 0 || filename == null || filename.length() == 0 || !filename.startsWith( basedir ) ) { return ""; } /* * Normalize the arguments. First, determine the file separator that is being used, then strip that off the end * of both the base directory and filename. */ String separator = determineSeparator( filename ); basedir = StringUtils.chompLast( basedir, separator ); filename = StringUtils.chompLast( filename, separator ); /* * Remove the base directory from the filename to end up with a relative filename (relative to the base * directory). This filename is then used to determine the relative path. */ String relativeFilename = filename.substring( basedir.length() ); return determineRelativePath( relativeFilename, separator ); } /** *

Determines the relative path of a filename. This method is useful in building relative links within pages of a * web site. It provides similar functionality to Anakia's $relativePath context variable. The argument * to this method may contain either forward or backward slashes as file separators. The relative path returned is * formed using forward slashes as it is expected this path is to be used as a link in a web page (again mimicking * Anakia's behavior).

* *

This method is thread-safe.

* * @param filename The filename to be parsed. * @return The relative path of the filename. This value is not terminated with a forward slash. A zero-length * string is returned if: filename is null or zero-length. * @see #getRelativeFilePath(String, String) */ public static final String getRelativePath( String filename ) { filename = uppercaseDrive( filename ); if ( filename == null || filename.length() == 0 ) { return ""; } /* * Normalize the argument. First, determine the file separator that is being used, then strip that off the end * of the filename. Then, if the filename doesn't begin with a separator, add one. */ String separator = determineSeparator( filename ); filename = StringUtils.chompLast( filename, separator ); if ( !filename.startsWith( separator ) ) { filename = separator + filename; } return determineRelativePath( filename, separator ); } /** *

Determines the directory component of a filename. This is useful within DVSL templates when used in conjunction * with the DVSL's $context.getAppValue("infilename") to get the current directory that is currently * being processed.

* *

This method is thread-safe.

* *
     * PathTool.getDirectoryComponent( null )                                   = ""
     * PathTool.getDirectoryComponent( "/usr/local/java/bin" )                  = "/usr/local/java"
     * PathTool.getDirectoryComponent( "/usr/local/java/bin/" )                 = "/usr/local/java/bin"
     * PathTool.getDirectoryComponent( "/usr/local/java/bin/java.sh" )          = "/usr/local/java/bin"
     * 
* * @param filename The filename to be parsed. * @return The directory portion of the filename. If the filename does not contain a directory * component, "." is returned. */ public static final String getDirectoryComponent( String filename ) { if ( filename == null || filename.length() == 0 ) { return ""; } String separator = determineSeparator( filename ); String directory = StringUtils.chomp( filename, separator ); if ( filename.equals( directory ) ) { return "."; } return directory; } /** * Calculates the appropriate link given the preferred link and the relativePath of the document. * *
     * PathTool.calculateLink( "/index.html", "../.." )                                        = "../../index.html"
     * PathTool.calculateLink( "http://plexus.codehaus.org/plexus-utils/index.html", "../.." ) = "http://plexus.codehaus.org/plexus-utils/index.html"
     * PathTool.calculateLink( "/usr/local/java/bin/java.sh", "../.." )                        = "../../usr/local/java/bin/java.sh"
     * PathTool.calculateLink( "../index.html", "/usr/local/java/bin" )                        = "/usr/local/java/bin/../index.html"
     * PathTool.calculateLink( "../index.html", "http://plexus.codehaus.org/plexus-utils" )    = "http://plexus.codehaus.org/plexus-utils/../index.html"
     * 
* * @param link * @param relativePath * @return String */ public static final String calculateLink( String link, String relativePath ) { if ( link == null ) { link = ""; } if ( relativePath == null ) { relativePath = ""; } // This must be some historical feature if ( link.startsWith( "/site/" ) ) { return link.substring( 5 ); } // Allows absolute links in nav-bars etc if ( link.startsWith( "/absolute/" ) ) { return link.substring( 10 ); } // This traps urls like http:// if ( link.contains( ":" ) ) { return link; } // If relativepath is current directory, just pass the link through if ( StringUtils.equals( relativePath, "." ) ) { if ( link.startsWith( "/" ) ) { return link.substring( 1 ); } return link; } // If we don't do this, you can end up with ..//bob.html rather than ../bob.html if ( relativePath.endsWith( "/" ) && link.startsWith( "/" ) ) { return relativePath + "." + link.substring( 1 ); } if ( relativePath.endsWith( "/" ) || link.startsWith( "/" ) ) { return relativePath + link; } return relativePath + "/" + link; } /** * This method can calculate the relative path between two paths on a web site. * *
     * PathTool.getRelativeWebPath( null, null )                                          = ""
     * PathTool.getRelativeWebPath( null, "http://plexus.codehaus.org/" )                 = ""
     * PathTool.getRelativeWebPath( "http://plexus.codehaus.org/", null )                 = ""
     * PathTool.getRelativeWebPath( "http://plexus.codehaus.org/",
     *                      "http://plexus.codehaus.org/plexus-utils/index.html" )        = "plexus-utils/index.html"
     * PathTool.getRelativeWebPath( "http://plexus.codehaus.org/plexus-utils/index.html",
     *                      "http://plexus.codehaus.org/"                                 = "../../"
     * 
* * @param oldPath * @param newPath * @return a relative web path from oldPath. */ public static final String getRelativeWebPath( final String oldPath, final String newPath ) { if ( StringUtils.isEmpty( oldPath ) || StringUtils.isEmpty( newPath ) ) { return ""; } String resultPath = buildRelativePath( newPath, oldPath, '/' ); if ( newPath.endsWith( "/" ) && !resultPath.endsWith( "/" ) ) { return resultPath + "/"; } return resultPath; } /** * This method can calculate the relative path between two paths on a file system. * *
     * PathTool.getRelativeFilePath( null, null )                                   = ""
     * PathTool.getRelativeFilePath( null, "/usr/local/java/bin" )                  = ""
     * PathTool.getRelativeFilePath( "/usr/local", null )                           = ""
     * PathTool.getRelativeFilePath( "/usr/local", "/usr/local/java/bin" )          = "java/bin"
     * PathTool.getRelativeFilePath( "/usr/local", "/usr/local/java/bin/" )         = "java/bin"
     * PathTool.getRelativeFilePath( "/usr/local/java/bin", "/usr/local/" )         = "../.."
     * PathTool.getRelativeFilePath( "/usr/local/", "/usr/local/java/bin/java.sh" ) = "java/bin/java.sh"
     * PathTool.getRelativeFilePath( "/usr/local/java/bin/java.sh", "/usr/local/" ) = "../../.."
     * PathTool.getRelativeFilePath( "/usr/local/", "/bin" )                        = "../../bin"
     * PathTool.getRelativeFilePath( "/bin", "/usr/local/" )                        = "../usr/local"
     * 
* * Note: On Windows based system, the / character should be replaced by \ character. * * @param oldPath * @param newPath * @return a relative file path from oldPath. */ public static final String getRelativeFilePath( final String oldPath, final String newPath ) { if ( StringUtils.isEmpty( oldPath ) || StringUtils.isEmpty( newPath ) ) { return ""; } // normalise the path delimiters String fromPath = new File( oldPath ).getPath(); String toPath = new File( newPath ).getPath(); // strip any leading slashes if its a windows path if ( toPath.matches( "^\\[a-zA-Z]:" ) ) { toPath = toPath.substring( 1 ); } if ( fromPath.matches( "^\\[a-zA-Z]:" ) ) { fromPath = fromPath.substring( 1 ); } // lowercase windows drive letters. if ( fromPath.startsWith( ":", 1 ) ) { fromPath = Character.toLowerCase( fromPath.charAt( 0 ) ) + fromPath.substring( 1 ); } if ( toPath.startsWith( ":", 1 ) ) { toPath = Character.toLowerCase( toPath.charAt( 0 ) ) + toPath.substring( 1 ); } // check for the presence of windows drives. No relative way of // traversing from one to the other. if ( ( toPath.startsWith( ":", 1 ) && fromPath.startsWith( ":", 1 ) ) && ( !toPath.substring( 0, 1 ).equals( fromPath.substring( 0, 1 ) ) ) ) { // they both have drive path element but they dont match, no // relative path return null; } if ( ( toPath.startsWith( ":", 1 ) && !fromPath.startsWith( ":", 1 ) ) || ( !toPath.startsWith( ":", 1 ) && fromPath.startsWith( ":", 1 ) ) ) { // one has a drive path element and the other doesnt, no relative // path. return null; } String resultPath = buildRelativePath( toPath, fromPath, File.separatorChar ); if ( newPath.endsWith( File.separator ) && !resultPath.endsWith( File.separator ) ) { return resultPath + File.separator; } return resultPath; } // ---------------------------------------------------------------------- // Private methods // ---------------------------------------------------------------------- /** * Determines the relative path of a filename. For each separator within the filename (except the leading if * present), append the "../" string to the return value. * * @param filename The filename to parse. * @param separator The separator used within the filename. * @return The relative path of the filename. This value is not terminated with a forward slash. A zero-length * string is returned if: the filename is zero-length. */ private static final String determineRelativePath( String filename, String separator ) { if ( filename.length() == 0 ) { return ""; } /* * Count the slashes in the relative filename, but exclude the leading slash. If the path has no slashes, then * the filename is relative to the current directory. */ int slashCount = StringUtils.countMatches( filename, separator ) - 1; if ( slashCount <= 0 ) { return "."; } /* * The relative filename contains one or more slashes indicating that the file is within one or more * directories. Thus, each slash represents a "../" in the relative path. */ StringBuilder sb = new StringBuilder(); for ( int i = 0; i < slashCount; i++ ) { sb.append( "../" ); } /* * Finally, return the relative path but strip the trailing slash to mimic Anakia's behavior. */ return StringUtils.chop( sb.toString() ); } /** * Helper method to determine the file separator (forward or backward slash) used in a filename. The slash that * occurs more often is returned as the separator. * * @param filename The filename parsed to determine the file separator. * @return The file separator used within filename. This value is either a forward or backward slash. */ private static final String determineSeparator( String filename ) { int forwardCount = StringUtils.countMatches( filename, "/" ); int backwardCount = StringUtils.countMatches( filename, "\\" ); return forwardCount >= backwardCount ? "/" : "\\"; } /** * Cygwin prefers lowercase drive letters, but other parts of maven use uppercase * * @param path * @return String */ static final String uppercaseDrive( String path ) { if ( path == null ) { return null; } if ( path.length() >= 2 && path.charAt( 1 ) == ':' ) { path = Character.toUpperCase( path.charAt( 0 ) ) + path.substring( 1 ); } return path; } private static final String buildRelativePath( String toPath, String fromPath, final char separatorChar ) { // use tokeniser to traverse paths and for lazy checking StringTokenizer toTokeniser = new StringTokenizer( toPath, String.valueOf( separatorChar ) ); StringTokenizer fromTokeniser = new StringTokenizer( fromPath, String.valueOf( separatorChar ) ); int count = 0; // walk along the to path looking for divergence from the from path while ( toTokeniser.hasMoreTokens() && fromTokeniser.hasMoreTokens() ) { if ( separatorChar == '\\' ) { if ( !fromTokeniser.nextToken().equalsIgnoreCase( toTokeniser.nextToken() ) ) { break; } } else { if ( !fromTokeniser.nextToken().equals( toTokeniser.nextToken() ) ) { break; } } count++; } // reinitialise the tokenisers to count positions to retrieve the // gobbled token toTokeniser = new StringTokenizer( toPath, String.valueOf( separatorChar ) ); fromTokeniser = new StringTokenizer( fromPath, String.valueOf( separatorChar ) ); while ( count-- > 0 ) { fromTokeniser.nextToken(); toTokeniser.nextToken(); } String relativePath = ""; // add back refs for the rest of from location. while ( fromTokeniser.hasMoreTokens() ) { fromTokeniser.nextToken(); relativePath += ".."; if ( fromTokeniser.hasMoreTokens() ) { relativePath += separatorChar; } } if ( relativePath.length() != 0 && toTokeniser.hasMoreTokens() ) { relativePath += separatorChar; } // add fwd fills for whatevers left of newPath. while ( toTokeniser.hasMoreTokens() ) { relativePath += toTokeniser.nextToken(); if ( toTokeniser.hasMoreTokens() ) { relativePath += separatorChar; } } return relativePath; } }




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