com.ibm.oti.shared
Interface SharedClassHelperFactory

All Known Implementing Classes:
SharedClassHelperFactoryImpl

public interface SharedClassHelperFactory

SharedClassHelperFactory provides an interface used to create various types of SharedClassHelper for ClassLoaders.

ClassLoaders and SharedClassHelpers have a one-to-one relationship. Any attempts to get a helper for a ClassLoader that already has a different type of helper will result in a HelperAlreadyDefinedException.

There are 3 diferent types of SharedClassHelper:

1) SharedClassTokenHelper

Store and find classes using a String token generated by the ClassLoader. For use by ClassLoaders which require complete control over cache contents.

2) SharedClassURLHelper

Store and find classes using a URL location. Any URL may be used to store or find classes.
For use by ClassLoaders which do not have the concept of a classpath, which load classes from multiple locations.
Classes may only be stored using jar/zip or file URLs. Classes are automatically kept up-to-date by the cache.
Classes stored using SharedClassURLClasspathHelper may be found using this helper and vice-versa.

3) SharedClassURLClasspathHelper

Store and find classes using a URL classpath. URLs may be appended to the classpath at any time. The classpath may also be modified under certain cirumstances (see SharedClassURLClasspathHelper javadoc).
For use by ClassLoaders which load classes using a URL classpath.
Classes may only be stored using jar/zip or file URLs. Classes are automatically kept up-to-date by the cache.
Classes stored using SharedClassURLHelper may be found using this helper and vice-versa.

Version:
initial
Author:
OTI
See Also:
SharedClassTokenHelper, SharedClassURLHelper, SharedClassURLClasspathHelper

Method Summary
 SharedClassHelper findHelperForClassLoader(java.lang.ClassLoader loader)
          Utility function which returns a SharedClassHelper for a given ClassLoader.
 SharedClassTokenHelper getTokenHelper(java.lang.ClassLoader loader)
          Return a SharedClassTokenHelper for a given ClassLoader.
 SharedClassTokenHelper getTokenHelper(java.lang.ClassLoader loader, SharedClassFilter filter)
          Return a SharedClassTokenHelper for a given ClassLoader.
 SharedClassURLClasspathHelper getURLClasspathHelper(java.lang.ClassLoader loader, java.net.URL[] classpath)
          Return a SharedClassURLClasspathHelper for a given ClassLoader.
 SharedClassURLClasspathHelper getURLClasspathHelper(java.lang.ClassLoader loader, java.net.URL[] classpath, SharedClassFilter filter)
          Return a SharedClassURLClasspathHelper for a given ClassLoader.
 SharedClassURLHelper getURLHelper(java.lang.ClassLoader loader)
          Return a SharedClassURLHelper for a given ClassLoader.
 SharedClassURLHelper getURLHelper(java.lang.ClassLoader loader, SharedClassFilter filter)
          Return a SharedClassURLHelper for a given ClassLoader.
 

Method Detail

getTokenHelper

SharedClassTokenHelper getTokenHelper(java.lang.ClassLoader loader)
                                      throws HelperAlreadyDefinedException
Return a SharedClassTokenHelper for a given ClassLoader.

Creates a new SharedClassTokenHelper if one cannot be found, otherwise returns existing SharedClassTokenHelper.
Throws a HelperAlreadyDefinedException if the ClassLoader already has a different type of helper.
Returns null if a SecurityManager is installed and there is no SharedClassPermission for the ClassLoader specified.

Parameters:
loader - ClassLoader. ClassLoader to which this SharedClassTokenHelper will belong
Returns:
SharedClassTokenHelper. A new or existing SharedClassTokenHelper
Throws:
HelperAlreadyDefinedException
See Also:
SharedClassTokenHelper

getTokenHelper

SharedClassTokenHelper getTokenHelper(java.lang.ClassLoader loader,
                                      SharedClassFilter filter)
                                      throws HelperAlreadyDefinedException
Return a SharedClassTokenHelper for a given ClassLoader.

Creates a new SharedClassTokenHelper if one cannot be found, otherwise returns existing SharedClassTokenHelper.
Throws a HelperAlreadyDefinedException if the ClassLoader already has a different type of helper.
Returns null if a SecurityManager is installed and there is no SharedClassPermission for the ClassLoader specified.

Parameters:
loader - ClassLoader. ClassLoader to which this SharedClassTokenHelper will belong
filter - SharedClassURLFilter. Specify a filter which limits the classes that are found or stored in the cache
Returns:
SharedClassTokenHelper. A new or existing SharedClassTokenHelper
Throws:
HelperAlreadyDefinedException
See Also:
SharedClassTokenHelper

getURLHelper

SharedClassURLHelper getURLHelper(java.lang.ClassLoader loader)
                                  throws HelperAlreadyDefinedException
Return a SharedClassURLHelper for a given ClassLoader.

Creates a new SharedClassURLHelper if one cannot be found, otherwise returns existing SharedClassURLHelper.
Throws a HelperAlreadyDefinedException if the ClassLoader already has a different type of helper.
Returns null if a SecurityManager is installed and there is no SharedClassPermission for the ClassLoader specified.

Parameters:
loader - ClassLoader. ClassLoader to which this SharedClassURLHelper will belong
Returns:
SharedClassURLHelper. A new or existing SharedClassURLHelper
Throws:
HelperAlreadyDefinedException
See Also:
SharedClassURLHelper

getURLClasspathHelper

SharedClassURLClasspathHelper getURLClasspathHelper(java.lang.ClassLoader loader,
                                                    java.net.URL[] classpath)
                                                    throws HelperAlreadyDefinedException
Return a SharedClassURLClasspathHelper for a given ClassLoader.

Creates a new SharedClassURLClasspathHelper if one cannot be found, otherwise if the classpath specified matches the classpath of an existing helper, returns existing SharedClassURLClasspathHelper.
Throws a HelperAlreadyDefinedException if the ClassLoader already has a different type of helper OR if the ClassLoader has a SharedClassURLClasspathHelper with a different classpath.
Returns null if a SecurityManager is installed and there is no SharedClassPermission for the ClassLoader specified.

Parameters:
loader - ClassLoader. ClassLoader to which this SharedClassURLClasspathHelper will belong
classpath - URL[]. The current URL classpath of this ClassLoader
Returns:
SharedClassURLClasspathHelper. A new or existing SharedClassURLClasspathHelper
Throws:
HelperAlreadyDefinedException
See Also:
SharedClassURLClasspathHelper

getURLClasspathHelper

SharedClassURLClasspathHelper getURLClasspathHelper(java.lang.ClassLoader loader,
                                                    java.net.URL[] classpath,
                                                    SharedClassFilter filter)
                                                    throws HelperAlreadyDefinedException
Return a SharedClassURLClasspathHelper for a given ClassLoader.

Creates a new SharedClassURLClasspathHelper if one cannot be found, otherwise if the classpath specified matches the classpath of an existing helper, returns existing SharedClassURLClasspathHelper.
If a new SharedClassHelper is created, the specified SharedClassURLFilter is applied to it. If the filter argument is null, no filter is applied.
Throws a HelperAlreadyDefinedException if the ClassLoader already has a different type of helper OR if the ClassLoader has a SharedClassURLClasspathHelper with a different classpath.
Returns null if a SecurityManager is installed and there is no SharedClassPermission for the ClassLoader specified.

Parameters:
loader - ClassLoader. ClassLoader to which this SharedClassURLClasspathHelper will belong
classpath - URL[]. The current URL classpath of this ClassLoader
filter - SharedClassURLFilter. Specify a filter which limits the classes that are found or stored in the cache
Returns:
SharedClassURLClasspathHelper. A new or existing SharedClassURLClasspathHelper
Throws:
HelperAlreadyDefinedException
See Also:
SharedClassURLClasspathHelper, SharedClassFilter

getURLHelper

SharedClassURLHelper getURLHelper(java.lang.ClassLoader loader,
                                  SharedClassFilter filter)
                                  throws HelperAlreadyDefinedException
Return a SharedClassURLHelper for a given ClassLoader.

Creates a new SharedClassURLHelper if one cannot be found, otherwise returns existing SharedClassURLHelper.
If a new SharedClassHelper is created, the specified SharedClassURLFilter is applied to it. If the filter argument is null, no filter is applied.
Throws a HelperAlreadyDefinedException if the ClassLoader already has a different type of helper.
Returns null if a SecurityManager is installed and there is no SharedClassPermission for the ClassLoader specified.

Parameters:
loader - ClassLoader. ClassLoader to which this SharedClassURLHelper will belong
filter - SharedClassURLFilter. Specify a filter which limits the classes that are found or stored in the cache
Returns:
SharedClassURLHelper. A new or existing SharedClassURLHelper
Throws:
HelperAlreadyDefinedException
See Also:
SharedClassURLHelper, SharedClassFilter

findHelperForClassLoader

SharedClassHelper findHelperForClassLoader(java.lang.ClassLoader loader)
Utility function which returns a SharedClassHelper for a given ClassLoader.

Can be used to determine whether a given ClassLoader already has a helper, before calling a getter method.
Returns an existing SharedClassHelper or null.

Parameters:
loader - ClassLoader. ClassLoader which may or may not have a SharedClassHelper
Returns:
SharedClassHelper. A helper if one exists for this ClassLoader or null otherwise.
See Also:
SharedClassHelper