com.ibm.oti.shared
Class SharedClassURLHelperImpl

java.lang.Object
  extended by com.ibm.oti.shared.SharedAbstractHelper
      extended by com.ibm.oti.shared.SharedClassAbstractHelper
          extended by com.ibm.oti.shared.SharedClassURLHelperImpl
All Implemented Interfaces:
SharedClassHelper, SharedClassURLHelper, SharedHelper

public class SharedClassURLHelperImpl
extends SharedClassAbstractHelper
implements SharedClassURLHelper

Implementation of SharedClassURLHelper.

Version:
initial
Author:
OTI
See Also:
SharedClassURLHelper, SharedClassHelperFactory, SharedClassAbstractHelper

Field Summary
static boolean MINIMIZE_ENABLED
           
 
Method Summary
 byte[] findSharedClass(java.lang.String partition, java.net.URL path, java.lang.String className)
          Find a class in the shared cache using a specific URL, class name and user-defined partition (see "Partitions" above).
 byte[] findSharedClass(java.net.URL path, java.lang.String className)
          Find a class in the shared cache using a specific URL and class name.
 boolean setMinimizeUpdateChecks()
          Minimize update checking on jar files for optimal performance
 boolean storeSharedClass(java.lang.String partition, java.net.URL path, java.lang.Class clazz)
          Store a class in the shared cache using the URL location it was loaded from and a user-defined partition (see "Partitions" above).
 boolean storeSharedClass(java.net.URL path, java.lang.Class clazz)
          Store a class in the shared cache using the URL location it was loaded from.
 
Methods inherited from class com.ibm.oti.shared.SharedClassAbstractHelper
getSharingFilter, isSharedClassCookie, setSharingFilter
 
Methods inherited from class com.ibm.oti.shared.SharedAbstractHelper
getClassLoader
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface com.ibm.oti.shared.SharedClassHelper
getSharingFilter, setSharingFilter
 
Methods inherited from interface com.ibm.oti.shared.SharedHelper
getClassLoader
 

Field Detail

MINIMIZE_ENABLED

public static final boolean MINIMIZE_ENABLED
See Also:
Constant Field Values
Method Detail

setMinimizeUpdateChecks

public boolean setMinimizeUpdateChecks()
Description copied from interface: SharedClassURLHelper
Minimize update checking on jar files for optimal performance

By default, when a class is loaded from the shared class cache, the timestamp of the container it was originally loaded from is compared with the timestamp of the actual container on the filesystem. If the two do not match, the original class is marked stale and is not returned by findSharedClass(). These checks are not performed if the container is held open by the ClassLoader.
If the ClassLoader does not want to open the container, but doesn't want the timestamp to be constantly checked when classes are loaded, it should call this function immediately after the SharedClassURLHelper object has been created. Once this function has been called, each container timestamp is checked once and then is not checked again for the lifetime of the SharedClassURLHelper.
This feature cannot be unset.

Specified by:
setMinimizeUpdateChecks in interface SharedClassURLHelper
Returns:
boolean True if the feature has been successfully set, false otherwise.

findSharedClass

public byte[] findSharedClass(java.net.URL path,
                              java.lang.String className)
Description copied from interface: SharedClassURLHelper
Find a class in the shared cache using a specific URL and class name.

A class will be returned if it was stored against the same URL.
Null is returned if the class cannot be found or if it is stale (see "Dynamic Cache Updates" above).
To obtain an instance of the class, the byte[] returned must be passed to defineClass by the caller ClassLoader.
Also returns false if the URL at foundAtIndex is not a file URL or if the resource it refers to does not exist.

Specified by:
findSharedClass in interface SharedClassURLHelper
Parameters:
path - URL A URL path. Cannot be null.
className - String The name of the class to be found
Returns:
byte[] A byte array describing the class found, or null.

findSharedClass

public byte[] findSharedClass(java.lang.String partition,
                              java.net.URL path,
                              java.lang.String className)
Description copied from interface: SharedClassURLHelper
Find a class in the shared cache using a specific URL, class name and user-defined partition (see "Partitions" above).

A class will only be returned if it was stored against the same URL and using the same partition. Null is returned if the class cannot be found or if it is stale (see "Dynamic Cache Updates" above).
To obtain an instance of the class, the byte[] returned must be passed to defineClass by the caller ClassLoader.
Also returns false if the URL at foundAtIndex is not a file URL or if the resource it refers to does not exist.

Specified by:
findSharedClass in interface SharedClassURLHelper
Parameters:
partition - String. User-defined partition if finding modified bytecode (see "Partitions" above). Passing null is equivalent of calling non-partition findSharedClass call.
path - URL. A URL path. Cannot be null.
className - String. The name of the class to be found
Returns:
byte[]. A byte array describing the found class, or null.

storeSharedClass

public boolean storeSharedClass(java.net.URL path,
                                java.lang.Class clazz)
Description copied from interface: SharedClassURLHelper
Store a class in the shared cache using the URL location it was loaded from.

The class being stored must have been defined by the caller ClassLoader and must exist in the URL location specified. Returns true if the class is stored successfully or false otherwise.
Will return false if the class being stored was not defined by the caller ClassLoader.
Also returns false if the URL at foundAtIndex is not a file URL or if the resource it refers to does not exist.

Specified by:
storeSharedClass in interface SharedClassURLHelper
Parameters:
path - URL. The URL path that the class was loaded from. Cannot be null.
clazz - Class. The class to store in the shared cache
Returns:
boolean. True if the class was stored successfully, false otherwise.

storeSharedClass

public boolean storeSharedClass(java.lang.String partition,
                                java.net.URL path,
                                java.lang.Class clazz)
Description copied from interface: SharedClassURLHelper
Store a class in the shared cache using the URL location it was loaded from and a user-defined partition (see "Partitions" above).

The class being stored must have been defined by the caller ClassLoader and must exist in the URL location specified. Returns true if the class is stored successfully or false otherwise.
Will return false if the class being stored was not defined by the caller ClassLoader.
Also returns false if the URL at foundAtIndex is not a file URL or if the resource it refers to does not exist.

Specified by:
storeSharedClass in interface SharedClassURLHelper
Parameters:
partition - String. User-defined partition if storing modified bytecode (see "Partitions" above). Passing null is equivalent of calling non-partition storeSharedClass call.
path - URL. The URL path that the class was loaded from. Cannot be null.
clazz - Class. The class to store in the shared cache
Returns:
boolean. True if the class was stored successfully, false otherwise.