org.jaffa.util
Class URLHelper

java.lang.Object
  org.jaffa.util.URLHelper

public class URLHelper

extends Object

Utility class to manipulate URL's and provide some additional capability for using them.

Version:

1.0

Author:

PaulE

Field Summary

static String	DEFAULT_PAGE This is the default value for the initial page of the application
static String	PROTOCOL_CLASSPATH This contains the name of the URL protocol that implies the resouce can be located in the classpath
static String	PROTOCOL_WEBROOT This contains the name of the URL protocol that implies the resource can be found relative to the location of the web-root on the local file system, This assumes that you are running this inside a servlet, on a web server

Constructor Summary

URLHelper()

Method Summary

static String	buildUrl(String url, HttpServletRequest req) Build up a valid URL string based on the supplied source URL string.
static String	getBase(HttpServletRequest request) Based on a HttpRequest, this routine will ingure out the URL that represents the root of the web application.
static String	getFullUrl(HttpServletRequest request) Get a complete string based representation of a request's source URL include query parameters
static InputStream	getInputStream(String resourceName) This method will try to load the input resource off the classpath.
static URL	getUrl(String resourceName) Deprecated. Use the newExtendedURL() method.
static void	main(String[] args) Test rig
static URL	newExtendedURL(String url) Create a URL object from a string, this can handle the two new Custom URL protocols, 'classpath:///' and 'webroot:///'.

Methods inherited from class java.lang.Object

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

Field Detail

PROTOCOL_CLASSPATH

public static final String PROTOCOL_CLASSPATH

This contains the name of the URL protocol that implies the resouce can be located in the classpath

See Also:

Constant Field Values

PROTOCOL_WEBROOT

public static final String PROTOCOL_WEBROOT

This contains the name of the URL protocol that implies the resource can be found relative to the location of the web-root on the local file system, This assumes that you are running this inside a servlet, on a web server

See Also:

Constant Field Values

DEFAULT_PAGE

public static final String DEFAULT_PAGE

This is the default value for the initial page of the application

See Also:

Constant Field Values

Constructor Detail

URLHelper

public URLHelper()

Method Detail

getBase

public static String getBase(HttpServletRequest request)

Based on a HttpRequest, this routine will ingure out the URL that represents the root of the web application. It derives the URL protocol, host, port and application. An example of a returned string may be http://www.example.org/myApp/ or https://www.example.com:888/SecureApp/

Parameters:

request - A HttpRequest used to derive information about the root of the web applicatoin

Returns:

a string that represents the base URL for this web application

buildUrl

public static String buildUrl(String url,
                              HttpServletRequest req)

Build up a valid URL string based on the supplied source URL string. If the supplied string in null, use the string defined in DEFAULT_PAGE and append this to web root ( using URLHelper.getBase() ) If the supplied string already is a valid url, leave it as is. If it is currently invalid, see if it can be made valid by making it relative to the web application base ( using URLHelper.getBase() ), if so return this value If this still doesn't yield a valid url, assume it was null, and build it based on DEFAULT_PAGE and getBase()

Parameters:

url - The URL to build and validate

req - The httpRequest needed to derive the web app base

Returns:

A fully expressed valid URL

getFullUrl

public static String getFullUrl(HttpServletRequest request)

Get a complete string based representation of a request's source URL include query parameters

Parameters:

request - HttpRequest containing the url to extracts

Returns:

string representation of URL

getInputStream

public static InputStream getInputStream(String resourceName)
                                  throws IOException

This method will try to load the input resource off the classpath. If its not found, then it will look for it in the filesystem. A null will be returned, if the resource could not be located.

Parameters:

resourceName - the resource to be located.

Returns:

an input stream for reading from the resource.

Throws:

IOException - if any error occurs while opening the stream.

getUrl

public static URL getUrl(String resourceName)

Deprecated. Use the newExtendedURL() method.

This method will try to load the input resource off the classpath. If its not found, then it will look for it in the filesystem. A null will be returned, if the resource could not be located. This method merely invokes the newExtendedURL() method, returning a null if any exception is raised.

Parameters:

resourceName - the resource to be located.

Returns:

a URL for reading from the resource.

newExtendedURL

public static URL newExtendedURL(String url)
                          throws MalformedURLException

Create a URL object from a string, this can handle the two new Custom URL protocols, 'classpath:///' and 'webroot:///'. If either of these new ones are used they will be converted into the appropriate 'file://' format. If no protocol is specified, then it'll try to load the input resource off the classpath. If its not found, then it will look for the input resource in the filesystem.

Parameters:

url - source URL that may use one of the new protocols

Returns:

valid URL object, as these two new protocols are not really supported by the java.net.URL object

Throws:

MalformedURLException - if the supplied URL is not valid, or can't be translated into something that is valid

main

public static void main(String[] args)

Test rig

Parameters:

args - none required