org.mdiutil.lang

Class ResourceLoader

java.lang.Object

org.mdiutil.lang.ResourceLoader

Direct Known Subclasses:

ResourceUILoader

public class ResourceLoader
extends Object

Manages application resources. This class is useful to retrieve bundled resources. To use this class:

• Create the ResourceLoader with a choice of:
  • the reference package (if you want to retrieve bundled resources)
  • or the reference URL (if you want to retrieve external resources). This reference URL can either be the URL of a file or a directory
• get the different resources, which can be:
  • relative to the reference package or URL
  • absolute if the reference URL was a File

Remark: The resources can be: PropertyResourceBundles, Icons, or Images.

ClassLoader

By default the ClassLoader used to retrieve the resources is the current ContextClassLoader. However one of the constructors allows to create the class and specify which ClassLoader to use. It is important to consider that if you try to retrieve resources in jar files which are not part of the application or library ClassPath (such as jar files loaded at runtime), you will need to create an URLClassLoader to load these resources, because the original ContextClassLoader won't be able to load the resources in this jar file.

Example

For example, suppose that we have a Jar File loaded at runtime with the following structure:

 theJarFile.jar:
 ==> the
 ====> package
 ======> resource.xml
 

We could use the following code to retrieve the resource.xml resource:

 URL url = theJarFile.toURI().toURL();
 URL[] urls = new URL[1]
 urls[0] = url;

 ClassLoader parentLoader = Thread.currentThread().getContextClassLoader();
 URLClassLoader loader = new URLClassLoader(urls, parentLoader);

 ResourceLoader loader = new ResourceLoader("the/package", loader);
 URL resourceURL = loader.getURL("resource.xml");
 

Field Summary

Fields

Modifier and Type	Field and Description
protected ClassLoader	loader The class loader used to retrieve the resources.
protected String	pack The package path.
protected URL	resourceURL

Constructor Summary

Constructors

Constructor and Description
ResourceLoader(File file) Creates a new resource loader, fetching resources in the file File, which can be a directory.
ResourceLoader(String pack) Creates a new resource loader, retrieving resources in a package, using the current ContextClassLoader.
ResourceLoader(String pack, Class clazz) Creates a new resource loader, retrieving resources in the pack package, using the ClassLoader associated with a class.
ResourceLoader(String pack, ClassLoader loader) Creates a new resource loader, retrieving resources in the pack package, using a specified ClassLoader.
ResourceLoader(String pack, Object o) Creates a new resource loader, retrieving resources in the pack package, using the ClassLoader associated with an Object.
ResourceLoader(URL url) Creates a new resource loader, fetching resources in the url URL (which can be a directory).

Method Summary

Modifier and Type	Method and Description
static ResourceLoader	createFromContext(String pack) CreateResourceLoader to use the ClassLoader or the caller class.
static ResourceLoader	createFromContext(String pack, boolean useInternalAPI) CreateResourceLoader to use the ClassLoader or the caller class.
ClassLoader	getDefaultClassLoader() Return the default ClassLoader used by this Class.
String	getPackage() Return the ResourceLoader used package.
PropertyResourceBundle	getPropertyResourceBundle() Return the PropertyResourceBundle of the selected absolute URL.
PropertyResourceBundle	getPropertyResourceBundle(String bundle) Return the PropertyResourceBundle looking for the bundle in the resource package or URL.
InputStream	getResourceAsStream(String name) Return an InputStream for a resource, using the default ClassLoader.
InputStream	getResourceAsStream(String name, Class clazz) Return an InputStream for a resource, using the ClassLoader associated with the Class which is passed in the arguments.
InputStream	getResourceAsStream(String name, Object o) Return an InputStream for a resource, using the ClassLoader associated with the Object which is passed in the arguments.
static InputStream	getResourceAsStream(String pack, String name) Return an InputStream for a resource, using the current ContextClassLoader.
static InputStream	getResourceAsStream(String pack, String name, Class clazz) Return an InputStream for a resource, using the ClassLoader associated with the Class which is passed in the arguments.
static InputStream	getResourceAsStream(String pack, String name, ClassLoader loader) Return an InputStream for a resource, using the a specified ClassLoader.
static InputStream	getResourceAsStream(String pack, String name, Object o) Return an InputStream for a resource, using the ClassLoader associated with the Object which is passed in the arguments.
URL	getResourceURL() Return the resource URL.
URL	getURL(String path) Return the URL with a specified path, using the package provided at the class creation, and the default ClassLoader.
URL	getURL(String path, Class clazz) Return the URL with a specified path, using the package provided at the class creation, and the ClassLoader associated with the Class which is passed in the arguments.
URL	getURL(String path, ClassLoader loader) Return the URL with a specified path, using a specified ClassLoader.
URL	getURL(String path, Object o) Return the URL with a specified path, using the package provided at the class creation, and the ClassLoader associated with the Object which is passed in the arguments.
static URL	getURL(String pack, String name) Return an URL for a resource, using the current ContextClassLoader.
static URL	getURL(String pack, String name, ClassLoader loader) Return an URL for a resource, using a specified ClassLoader.

Methods inherited from class java.lang.Object

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

Field Detail

resourceURL

protected URL resourceURL

pack

protected String pack

The package path.

loader

protected ClassLoader loader

The class loader used to retrieve the resources.

Constructor Detail

ResourceLoader

public ResourceLoader(String pack)

Creates a new resource loader, retrieving resources in a package, using the current ContextClassLoader. Example:

 ResourceLoader loader = new ResourceLoader("svglab/resources");
 

It is useful to retrieve bundled resources.

Parameters:

pack - the package

ResourceLoader

public ResourceLoader(String pack,
                      ClassLoader loader)

Creates a new resource loader, retrieving resources in the pack package, using a specified ClassLoader. Example:

 ResourceLoader loader = new ResourceLoader("mypack/resources", myClassLoader);
 

Parameters:

pack - the package

loader - the ClassLoader

ResourceLoader

public ResourceLoader(String pack,
                      Class clazz)

Creates a new resource loader, retrieving resources in the pack package, using the ClassLoader associated with a class. Example:

 ResourceLoader loader = new ResourceLoader("mypack/resources", myClassLoader);
 

Parameters:

pack - the package

clazz - the class used to get the Class loader

ResourceLoader

public ResourceLoader(String pack,
                      Object o)

Creates a new resource loader, retrieving resources in the pack package, using the ClassLoader associated with an Object. Example:

 ResourceLoader loader = new ResourceLoader("mypack/resources", myClassLoader);
 

Parameters:

pack - the package

o - the Object used to get the Class loader

ResourceLoader

public ResourceLoader(File file)

Creates a new resource loader, fetching resources in the file File, which can be a directory. It is useful to retrieve use properties resources.

Parameters:

file - the File

ResourceLoader

public ResourceLoader(URL url)

Creates a new resource loader, fetching resources in the url URL (which can be a directory).

Parameters:

url - the URL

Method Detail

createFromContext

public static ResourceLoader createFromContext(String pack)

CreateResourceLoader to use the ClassLoader or the caller class. Defer to createFromContext(java.lang.String, boolean) with false for the second argument

Parameters:

pack - the package

Returns:

a ResourceLoader

createFromContext

public static ResourceLoader createFromContext(String pack,
                                               boolean useInternalAPI)

CreateResourceLoader to use the ClassLoader or the caller class.

Parameters:

pack - the package

useInternalAPI - true if the sun.reflect.Reflection will be used

Returns:

a ResourceLoader

getResourceURL

public URL getResourceURL()

Return the resource URL.

Returns:

the resource URL

getPackage

public String getPackage()

Return the ResourceLoader used package.

Returns:

the ResourceLoader used package

getDefaultClassLoader

public ClassLoader getDefaultClassLoader()

Return the default ClassLoader used by this Class.

Returns:

the default ClassLoader used by this Class

getPropertyResourceBundle

public PropertyResourceBundle getPropertyResourceBundle()

Return the PropertyResourceBundle of the selected absolute URL.

Returns:

the PropertyResourceBundle

getPropertyResourceBundle

public PropertyResourceBundle getPropertyResourceBundle(String bundle)

Return the PropertyResourceBundle looking for the bundle in the resource package or URL. This method will use the default ClassLoader.

Parameters:

bundle - the bundle

Returns:

the PropertyResourceBundle

getURL

public URL getURL(String path)

Return the URL with a specified path, using the package provided at the class creation, and the default ClassLoader. The package will be the package specified at the class creation (see getPackage()). There are two cases for returning the URL:

• If the package is null, return the URL as an absolute URL
• If the package is not null, return the URL as an URL relative to the package

Parameters:

path - the path

Returns:

the URL, or null if the class was not created specifying a package

getURL

public URL getURL(String path,
                  ClassLoader loader)

Return the URL with a specified path, using a specified ClassLoader. The package will be the package specified at the class creation (see getPackage()). There are two cases for returning the URL:

• If the package is null, return the URL as an absolute URL
• If the package is not null, return the URL as an URL relative to the package

Parameters:

loader - the ClassLoader

path - the path

Returns:

the URL, or null if the class was not created specifying a package

getURL

public URL getURL(String path,
                  Class clazz)

Return the URL with a specified path, using the package provided at the class creation, and the ClassLoader associated with the Class which is passed in the arguments. The package will be the package specified at the class creation (see getPackage()). There are two cases for returning the URL:

• If the package is null, return the URL as an absolute URL
• If the package is not null, return the URL as an URL relative to the package

Parameters:

clazz - the Class used to get the ClassLoader

path - the path

Returns:

the URL, or null if the class was not created specifying a package

getURL

public URL getURL(String path,
                  Object o)

Return the URL with a specified path, using the package provided at the class creation, and the ClassLoader associated with the Object which is passed in the arguments. The package will be the package specified at the class creation (see getPackage()). There are two cases for returning the URL:

• If the package is null, return the URL as an absolute URL
• If the package is not null, return the URL as an URL relative to the package

Parameters:

o - the Object used to get the ClassLoader

path - the path

Returns:

the URL, or null if the class was not created specifying a package

getURL

public static URL getURL(String pack,
                         String name)

Return an URL for a resource, using the current ContextClassLoader. The package will be the package specified at the class creation (see getPackage()).

Parameters:

pack - the package

name - the resource name

Returns:

the resource URL, or null if the class was not created specifying a package

getURL

public static URL getURL(String pack,
                         String name,
                         ClassLoader loader)

Return an URL for a resource, using a specified ClassLoader. The package will be the package specified at the class creation (see getPackage()).

Parameters:

pack - the package

name - the resource name

loader - the ClassLoader

Returns:

the resource URL, or null if the class was not created specifying a package

getResourceAsStream

public InputStream getResourceAsStream(String name)

Return an InputStream for a resource, using the default ClassLoader. The package will be the package specified at the class creation (see getPackage()).

Parameters:

name - the resource name

Returns:

the resource URL, or null if the class was not created specifying a package

getResourceAsStream

public InputStream getResourceAsStream(String name,
                                       Class clazz)

Return an InputStream for a resource, using the ClassLoader associated with the Class which is passed in the arguments. The package will be the package specified at the class creation (see getPackage()).

Parameters:

name - the resource name

clazz - the Class used to get the ClassLoader

Returns:

the resource URL, or null if the class was not created specifying a package

getResourceAsStream

public InputStream getResourceAsStream(String name,
                                       Object o)

Return an InputStream for a resource, using the ClassLoader associated with the Object which is passed in the arguments. The package will be the package specified at the class creation (see getPackage()).

Parameters:

name - the resource name

o - the Object used to get the ClassLoader

Returns:

the resource URL, or null if the class was not created specifying a package

getResourceAsStream

public static InputStream getResourceAsStream(String pack,
                                              String name)

Return an InputStream for a resource, using the current ContextClassLoader.

Parameters:

pack - the package

name - the resource name

Returns:

the resource URL

getResourceAsStream

public static InputStream getResourceAsStream(String pack,
                                              String name,
                                              ClassLoader loader)

Return an InputStream for a resource, using the a specified ClassLoader.

Parameters:

pack - the package

name - the resource name

loader - the ClassLoader

Returns:

the resource URL

getResourceAsStream

public static InputStream getResourceAsStream(String pack,
                                              String name,
                                              Class clazz)

Return an InputStream for a resource, using the ClassLoader associated with the Class which is passed in the arguments.

Parameters:

pack - the package

name - the resource name

clazz - the Class used to get the ClassLoader

Returns:

the resource URL

getResourceAsStream

public static InputStream getResourceAsStream(String pack,
                                              String name,
                                              Object o)

Return an InputStream for a resource, using the ClassLoader associated with the Object which is passed in the arguments.

Parameters:

pack - the package

name - the resource name

o - the Object used to get the ClassLoader

Returns:

the resource URL