org.simpleframework.http.parse
Class PathParser

java.lang.Object
  org.simpleframework.common.parse.Parser
      org.simpleframework.http.parse.PathParser

All Implemented Interfaces:

Path

public class PathParser
extends Parser
implements Path

This is used to parse a path given as part of a URI. This will read the path, normalize it, and break it up into its components. The normalization of the path is the conversion of the path given into it's actual path by removing the references to the parent directories and to the current dir.

If the path that this represents is /usr/bin/../etc/./README then the actual path, normalized, is /usr/etc/README. Once the path has been normalized it is possible to acquire the segments as an array of strings, which allows simple manipulation of the path.

Although RFC 2396 defines the path within a URI to have parameters this does not extract those parameters this will simply normalize the path and include the path parameters in the path. If the path is to be converted into a OS specific file system path that has the parameters extracted then the AddressParser should be used.

Author:

Niall Gallagher

Field Summary

Fields inherited from class org.simpleframework.common.parse.Parser

buf, count, off

Constructor Summary

PathParser()
The default constructor will create a PathParser that contains no specifics.

PathParser(String path)
This is primarily a convineance constructor.

Method Summary

String	getDirectory() This will return the highest directory that exists within the path.
String	getExtension() This will return the extension that the file name contains.
String	getName() This will return the full name of the file without the path.
String	getPath() This will return the normalized path.
String	getPath(int from) This will return the normalized path from the specified path segment.
String	getPath(int from, int count) This will return the normalized path from the specified path segment.
String	getRelative(String path) This will return the path as it is relative to the issued path.
String[]	getSegments() This method is used to break the path into individual parts called segments, see RFC 2396.
protected void	init() This will initialize the parser so that it is in a ready state.
protected void	parse() This will parse the path in such a way that it ensures that at no stage there are trailing back references, using path normalization.
String	toString() This will return the normalized path.

Methods inherited from class org.simpleframework.common.parse.Parser

digit, ensureCapacity, parse, skip, space, toLower

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

PathParser

public PathParser()

The default constructor will create a PathParser that contains no specifics. The instance will return null for all the get methods. The PathParser's get methods may be populated by using the parse method.

PathParser

public PathParser(String path)

This is primarily a convineance constructor. This will parse the String given to extract the specifics. This could be achived by calling the default no-arg constructor and then using the instance to invoke the parse method on that String to extract the parts.

Parameters:

path - a String containing a path value

Method Detail

parse

protected void parse()

This will parse the path in such a way that it ensures that at no stage there are trailing back references, using path normalization. The need to remove the back references is so that this PathParser will create the same String path given a set of paths that have different back references. For example the paths /path/../path and /path are the same path but different String's.

This will NOT parse an immediate back reference as this signifies a path that cannot exist. So a path such as /../ will result in a null for all methods. Paths such as ../bin will not be allowed.

Specified by:

parse in class Parser

init

protected void init()

This will initialize the parser so that it is in a ready state. This allows the parser to be used to parse many paths. This will clear the parse buffer objects and reset the offset to point to the start of the char buffer. The count variable is reset by the Parser.parse method.

Specified by:

init in class Parser

getExtension

public String getExtension()

This will return the extension that the file name contains. For example a file name file.en_US.extension will produce an extension of extension. This will return null if the path contains no file extension.

Specified by:

getExtension in interface Path

Returns:

this will return the extension this path contains

getName

public String getName()

This will return the full name of the file without the path. As regargs the definition of the path in RFC 2396 the name would be considered the last path segment. So if the path was /usr/README the name is README. Also for directorys the name of the directory in the last path segment is returned. This returns the name without any of the path parameters. As RFC 2396 defines the path to have path parameters after the path segments.

Specified by:

getName in interface Path

Returns:

this will return the name of the file in the path

getPath

public String getPath()

This will return the normalized path. The normalized path is the path without any references to its parent or itself. So if the path to be parsed is /usr/../etc/./ the path is /etc/. If the path that this represents is a path with an immediate back reference then this will return null. This is the path with all its information even the parameter information if it was defined in the path.

Specified by:

getPath in interface Path

Returns:

this returns the normalize path without ../ or ./

getPath

public String getPath(int from)

This will return the normalized path from the specified path segment. This allows various path parts to be acquired in an efficient means what does not require copy operations of the use of substring invocations. Of particular interest is the extraction of context based paths. This is the path with all its information even the parameter information if it was defined in the path.

Specified by:

getPath in interface Path

Parameters:

from - this is the segment offset to get the path for

Returns:

this returns the normalize path without ../ or ./

getPath

public String getPath(int from,
                      int count)

This will return the normalized path from the specified path segment. This allows various path parts to be acquired in an efficient means what does not require copy operations of the use of substring invocations. Of particular interest is the extraction of context based paths. This is the path with all its information even the parameter information if it was defined in the path.

Specified by:

getPath in interface Path

Parameters:

from - this is the segment offset to get the path for

count - this is the number of path segments to include

Returns:

this returns the normalize path without ../ or ./

getDirectory

public String getDirectory()

This will return the highest directory that exists within the path. This is used to that files within the same path can be acquired. An example of that this would do given the path /pub/./bin/README would be to return the highest directory path /pub/bin/. The "/" character will allways be the last character in the path.

Specified by:

getDirectory in interface Path

Returns:

this method will return the highest directory

getSegments

public String[] getSegments()

This method is used to break the path into individual parts called segments, see RFC 2396. This can be used as an easy way to compare paths and to examine the directory tree that the path points to. For example, if an path was broken from the string /usr/bin/../etc then the segments returned would be usr and etc as the path is normalized before the segments are extracted.

Specified by:

getSegments in interface Path

Returns:

return all the path segments within the directory

getRelative

public String getRelative(String path)

This will return the path as it is relative to the issued path. This in effect will chop the start of this path if it's start matches the highest directory of the given path as of getDirectory. This is useful if paths that are relative to a specific location are required. To illustrate what this method will do the following example is provided. If this object represented the path string /usr/share/rfc/rfc2396.txt and the issued path was /usr/share/text.txt then this will return the path string /rfc/rfc2396.txt.

Specified by:

getRelative in interface Path

Parameters:

path - the path prefix to acquire a relative path

Returns:

returns a path relative to the one it is given otherwize this method will return null

toString

public String toString()

This will return the normalized path. The normalized path is the path without any references to its parent or itself. So if the path to be parsed is /usr/../etc/./ the path is /etc/. If the path that this represents is a path with an immediate back reference then this will return null. This is the path with all its information even the parameter information if it was defined in the path.

Specified by:

toString in interface Path

Overrides:

toString in class Object

Returns:

this returns the normalize path without ../ or ./