PathElement and Path
* objects. It is used to represent a classpath or path like nested parameters
* in task definitions:
*
*
* <sometask>
* <somepath>
* <element location="/path/to/file.jar" />
* <element path="/path/to/file2.jar:/path/to/class2;/path/to/class3" />
* <element location="/path/to/file3.jar" />
* <element location="/path/to/file4.jar" />
* </somepath>
* </sometask>
* *
* The object implemention sometask must provide a method called
* createSomepath which returns an instance of Path.
* Nested path definitions are handled by the Path object and must be labeled
* path.
*
* The path element takes a parameter path which will be parsed
* and split into PathElement objects. It will usually be used
* to define a path from an environment variable.
*
* @author Thomas.Haas@softwired-inc.com
*/
public class Path {
private Vector definition = new Vector();
private PathElement element = null;
/**
* Handles a single element definition.
* Each Path object creates at most one PathElement object. PathElement
* objects can be shared, as they are currently stateless.
**/
public class PathElement {
/**
* Adds a element definition to the path.
* @param location the location of the element to add (must not be
* null nor empty.
**/
public void setLocation(String location) {
if (location != null && location.length() > 0) {
definition.addElement(new File(location));
}
}
/**
* Parses a path definition and creates single PatheElements.
* @param path the path definition.
*/
public void setPath(String path) {
// TODO: could be improved, iftranslatePath returns list instead
// of a string.
final StringTokenizer tokenizer = new StringTokenizer(
translatePath(path), File.pathSeparator, false);
while(tokenizer.hasMoreTokens()) {
setLocation(tokenizer.nextToken());
}
}
}
/**
* Creates a PathElement for path element definitions.
* @return an empty PathElement object.
*/
public PathElement createElement() {
if (element == null) {
element = new PathElement();
}
return element;
}
/**
* Creates a nested path object.
* @return a nested path object.
*/
public Path createPath() {
return this;
}
/**
* Returns all path elements defined by this and netsed path objects.
* @return list of path elements.
*/
public File[] list() {
final File[] result = new File[definition.size()];
definition.copyInto(result);
return result;
}
/**
* Returns a textual representation of the path, which can be used as
* CLASSPATH or PATH environment variable definition.
* @return a textual representation of the path.
*/
public String toString() {
final File[] list = list();
// empty path return empty string
if (list.length == 0) return "";
// path containing one or more elements
final StringBuffer result = new StringBuffer(list[0].toString());
for (int i=1; i < list.length; i++) {
result.append(File.pathSeparatorChar);
result.append(list[i]);
}
return result.toString();
}
/**
Translate a path into its native (platform specific)
path. This should be extremely fast, code is
borrowed from ECS project.
All it does is translate the : into ; and / into \ if needed. In other words, it isn't perfect. @returns translated string or empty string if to_process is null or empty @author Jon S. Stevens jon@clearink.com */ public static String translatePath(String to_process) { // TODO: Improve by getting rid of temp creation of strings by only // working with characters. // Return list of strings instead of String to ease further // processing. if ( to_process == null || to_process.length() == 0 ) return ""; final StringBuffer bs = new StringBuffer(to_process.length() + 50); final StringCharacterIterator sci = new StringCharacterIterator(to_process); final String path = File.pathSeparator; final String file = File.separator; for (char c = sci.first(); c != CharacterIterator.DONE; c = sci.next()) { String tmp = String.valueOf(c); if (tmp.equals(":")) { // could be a DOS drive or a Unix path separator... // if followed by a backslash, assume it is a drive c = sci.next(); tmp = String.valueOf(c); bs.append( tmp.equals("\\") ? ":" : path ); if (c == CharacterIterator.DONE) break; } if (tmp.equals(":") || tmp.equals(";")) tmp = path; else if (tmp.equals("/") || tmp.equals ("\\")) tmp = file; bs.append(tmp); } return bs.toString(); } }