org.crosswire.common.util

Class CWClassLoader

java.lang.Object

java.lang.ClassLoader

org.crosswire.common.util.CWClassLoader

public final class CWClassLoader
extends ClassLoader

CWClassLoader extends the regular class loader by using looking in more places. This is needed so that ResourceBundle can find resources that are not held in the same package as the class. This is expressed as a list of locations, called homes, that the program will look in.

Author:

DM Smith

See Also:

The GNU Lesser General Public License for details.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	CWClassLoader.PrivilegedLoader<T> PrivilegedLoader creates a CWClassLoader if it is able to obtain java security permissions to do so.

Field Summary

Fields

Modifier and Type	Field and Description
private static URI[]	homes Notion of a project's home from where additional resources can be found.
private Class<?>	owner The class to which the resources belong

Constructor Summary

Constructors

Constructor and Description
CWClassLoader() Creates a class loader that finds resources for the calling class that may not be in the class' package.
CWClassLoader(Class<?> resourceOwner) Creates a class loader that finds resources for the supplied class that may not be in the class' package.

Method Summary

Methods

Modifier and Type	Method and Description
private String	adjustPackageSearch(String aSearch) Prefix the search with a package prefix, if not already.
private String	adjustPathSearch(String aSearch) Change all but a leading '/' to '.'
static URI	findHomeResource(String search) Look for the resource in the home directories, returning the first readable file.
URL	findResource(String search)
ClassLoader	getClassLoader() Pick the best class loader
static URI	getHome(int i) If the application has set the homes, it will return the application's requested home directory, otherwise it returns null.
static CWClassLoader	instance() Creates a privileged class loader that finds resources for the calling class that may not be in the class' package.
static CWClassLoader	instance(Class<?> resourceOwner) Creates a privileged class loader that finds resources for the supplied class that may not be in the class' package.
private static ClassLoader	pickLoader(ClassLoader loader1, ClassLoader loader2) Returns 'true' if 'loader2' is a delegation child of 'loader1' [or if 'loader1'=='loader2'].
static void	setHome(URI[] newHomes) Establish the applications home directory from where additional resources can be found.

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findClass, findLibrary, findLoadedClass, findResources, findSystemClass, getClassLoadingLock, getPackage, getPackages, getParent, getResource, getResourceAsStream, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, loadClass, loadClass, registerAsParallelCapable, resolveClass, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Field Detail

owner

private Class<?> owner

The class to which the resources belong

homes

private static URI[] homes

Notion of a project's home from where additional resources can be found.

Constructor Detail

CWClassLoader

CWClassLoader(Class<?> resourceOwner)

Creates a class loader that finds resources for the supplied class that may not be in the class' package. You can use this within base classes by passing getClass() to load resources for a derived class.

Parameters:

resourceOwner - is the owner of the resource

CWClassLoader

CWClassLoader()

Creates a class loader that finds resources for the calling class that may not be in the class' package. Use this only within classes that are directly looking up their resources.

Method Detail

instance

public static CWClassLoader instance(Class<?> resourceOwner)

Creates a privileged class loader that finds resources for the supplied class that may not be in the class' package. You can use this within base classes by passing getClass() to load resources for a derived class.

Parameters:

resourceOwner - is the owner of the resource

Returns:

the CrossWire Class Loader

instance

public static CWClassLoader instance()

Creates a privileged class loader that finds resources for the calling class that may not be in the class' package. Use this only within classes that are directly looking up their resources.

Returns:

the CrossWire Class Loader

findResource

public URL findResource(String search)

Overrides:

findResource in class ClassLoader

adjustPackageSearch

private String adjustPackageSearch(String aSearch)

Prefix the search with a package prefix, if not already. Skip a leading '/' if present.

Parameters:

aSearch - the search to adjust

Returns:

the adjusted search

adjustPathSearch

private String adjustPathSearch(String aSearch)

Change all but a leading '/' to '.'

Parameters:

aSearch - the search to adjust

Returns:

the adjusted search

getClassLoader

public ClassLoader getClassLoader()

Pick the best class loader

Returns:

the class loader

pickLoader

private static ClassLoader pickLoader(ClassLoader loader1,
                     ClassLoader loader2)

Returns 'true' if 'loader2' is a delegation child of 'loader1' [or if 'loader1'=='loader2']. Of course, this works only for classloaders that set their parent pointers correctly. 'null' is interpreted as the primordial loader [i.e., everybody's parent].

Parameters:

loader1 - a class loader to consider

loader2 - a class loader to consider

Returns:

one of the class loaders

getHome

public static URI getHome(int i)

If the application has set the homes, it will return the application's requested home directory, otherwise it returns null.

Parameters:

i - get the i-th home

Returns:

Returns the home.

setHome

public static void setHome(URI[] newHomes)

Establish the applications home directory from where additional resources can be found. URL is expected to end with the directory name, not '/'.

Parameters:

newHomes - The home to set.

findHomeResource

public static URI findHomeResource(String search)

Look for the resource in the home directories, returning the first readable file.

Parameters:

search - must be non-null, non-empty

Returns:

the URI of the home of the resource