Package ch.hevs.utils

Class ResourceLoader

java.lang.Object

ch.hevs.utils.ResourceLoader

public class ResourceLoader
extends java.lang.Object

Offers a consistent interface in order to load resources from either the file system, the classpath (JAR bundle), the OSGI bundle or from an http server.

The resource has to be given using an URI scheme as for example "file:/etc/my_config.conf". The following URI schemes are supported:

• 
  classpath:
  The file is located in the classpath (Either in the JAR file or inside the same OSGi Bundle).
• 
  file:
  The file is located on the local file system. An absolute path to the file has to be given.
• 
  home:
  The file is located in the home directory of the actual user. The given path is relative to the user's home directory.
• 
  http:
  The resource (file) is located on an HTTP server and will be downloaded on demand.

Constructor Summary

Constructors

Constructor	Description
ResourceLoader()

Method Summary

Modifier and Type	Method	Description
static java.io.InputStream	getResource(java.lang.String location, java.lang.Object target)	Locates the requested resource and returns an open InputStream if the requested resource could be located, otherwise an exception will be thrown.
static java.io.InputStream	getResource(java.net.URI uri, java.lang.Object target)	Locates the requested resource and returns an open InputStream if the requested resource could be located, otherwise an exception will be thrown.
static java.io.InputStream	getResourceFromLocations(java.lang.String filename, java.lang.Object target, java.lang.String... locations)	Tries to open an input stream for the given file name by trying to open the stream from the given locations one after another.

Methods inherited from class java.lang.Object

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

Constructor Detail

ResourceLoader

public ResourceLoader()

Method Detail

getResource

public static java.io.InputStream getResource(java.lang.String location,
                                              java.lang.Object target)
                                       throws java.net.URISyntaxException,
                                              java.io.IOException

Locates the requested resource and returns an open InputStream if the requested resource could be located, otherwise an exception will be thrown. See ResourceLoader for supported URI schemes.

Parameters:

location - Location as URI of the resource/file.

target - The object which will use the resource, this is only important when the URI scheme is "classpath" as the class loader of the given class will be used in order to find the resource.

Returns:

Ready to use input stream of the resource.

Throws:

java.io.FileNotFoundException - If the file could not be found.

java.net.URISyntaxException - The syntax of the given URI is invalid.

java.net.MalformedURLException - The URL in the case the scheme is http is invalid.

java.io.IOException - Any other exception that can happen during opening a resource.

getResource

public static java.io.InputStream getResource(java.net.URI uri,
                                              java.lang.Object target)
                                       throws java.net.URISyntaxException,
                                              java.io.IOException

Locates the requested resource and returns an open InputStream if the requested resource could be located, otherwise an exception will be thrown. See ResourceLoader for supported URI schemes.

Parameters:

uri - Location of the resource/file.

target - The object which will use the resource, this is only important when the URI scheme is "classpath" as the class loader of the given class will be used in order to find the resource.

Returns:

Ready to use input stream of the resource.

Throws:

java.io.FileNotFoundException - If the file could not be found.

java.net.URISyntaxException - The syntax of the given URI is invalid.

java.net.MalformedURLException - The URL in the case the scheme is http is invalid.

java.io.IOException - Any other exception that can happen during opening a resource.

getResourceFromLocations

public static java.io.InputStream getResourceFromLocations(java.lang.String filename,
                                                           java.lang.Object target,
                                                           java.lang.String... locations)
                                                    throws java.io.FileNotFoundException

Tries to open an input stream for the given file name by trying to open the stream from the given locations one after another. Once the file could be found in one of the given locations, the input stream to that resource is returned. See ResourceLoader for supported URI schemes.

Parameters:

filename - File name of the resource to open.

target - The object which will use the resource, this is only important when the URI scheme is "classpath" as the class loader of the given class will be used in order to find the resource.

locations - All the locations as URIs to search for.

Returns:

Ready to use input stream of the resource.

Throws:

java.io.FileNotFoundException - If the file could not be found in any of the given locations.