com.ibm.oti.shared
Class SharedClassURLClasspathHelperImpl

java.lang.Object
  extended by com.ibm.oti.shared.SharedClassAbstractHelper
      extended by com.ibm.oti.shared.SharedClassURLClasspathHelperImpl
All Implemented Interfaces:
SharedClassHelper, SharedClassURLClasspathHelper

public class SharedClassURLClasspathHelperImpl
extends SharedClassAbstractHelper
implements SharedClassURLClasspathHelper

Implementation of SharedClassURLClasspathHelper.

Version:
initial
Author:
OTI
See Also:
SharedClassTokenHelper, SharedClassHelperFactory

Nested Class Summary
 
Nested classes/interfaces inherited from interface com.ibm.oti.shared.SharedClassURLClasspathHelper
SharedClassURLClasspathHelper.IndexHolder
 
Method Summary
 void addClasspathEntry(java.net.URL cpe)
          Update the helper's classpath by appending a URL (see "Usage" above).
 void confirmAllEntries()
          Confirms all entries in the classpath.
 byte[] findSharedClass(java.lang.String className, SharedClassURLClasspathHelper.IndexHolder indexFoundAtHolder)
          Find a class in the shared cache using the class name given (implicitly using the caller's classpath).
 byte[] findSharedClass(java.lang.String partition, java.lang.String className, SharedClassURLClasspathHelper.IndexHolder indexFoundAtHolder)
          Find a class in the shared cache using the class name and partition given (implicitly using the caller's classpath).
 void setClasspath(java.net.URL[] newClasspath)
          Update the helper's classpath with a new classpath.
 boolean storeSharedClass(java.lang.Class clazz, int foundAtIndex)
          Store a class in the shared cache using the caller's URL classpath.
 boolean storeSharedClass(java.lang.String partition, java.lang.Class clazz, int foundAtIndex)
          Store a class in the shared cache using the caller's URL classpath and with a user-defined partition.
 
Methods inherited from class com.ibm.oti.shared.SharedClassAbstractHelper
getClassLoader, isSharedClassCookie
 
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
getClassLoader
 

Method Detail

findSharedClass

public byte[] findSharedClass(java.lang.String className,
                              SharedClassURLClasspathHelper.IndexHolder indexFoundAtHolder)
Description copied from interface: SharedClassURLClasspathHelper
Find a class in the shared cache using the class name given (implicitly using the caller's classpath).

See "Using Classpaths" above for rules on when a class will be found
Null is returned if the class cannot be found, if it is stale (see "Dynamic Cache Updates" above) or if it is found for an unconfirmed entry (see "Using Classpaths" above).

Specified by:
findSharedClass in interface SharedClassURLClasspathHelper
Parameters:
className - String. The name of the class to be found
indexFoundAtHolder - IndexHolder. The index in the caller ClassLoader's classpath at which the class was found. This parameter can be null if this data is not needed.
Returns:
byte[]. A byte array describing the class found, or null.

findSharedClass

public byte[] findSharedClass(java.lang.String partition,
                              java.lang.String className,
                              SharedClassURLClasspathHelper.IndexHolder indexFoundAtHolder)
Description copied from interface: SharedClassURLClasspathHelper
Find a class in the shared cache using the class name and partition given (implicitly using the caller's classpath).

See "Finding Classes" above for rules on when a class will be found
Null is returned if the class cannot be found, if it is stale (see "Dynamic Cache Updates" above) or if it is found for an unconfirmed entry (see "Using Classpaths" above).

Specified by:
findSharedClass in interface SharedClassURLClasspathHelper
Parameters:
partition - String. User-defined partition if finding modified bytecode (see "Partitions" above). Passing null is equivalent of calling non-partition findSharedClass call.
className - String. The name of the class to be found
indexFoundAtHolder - IndexHolder. The index in the caller ClassLoader's classpath at which the class was found. This parameter can be null if this data is not needed.
Returns:
byte[]. A byte array describing the class found, or null.

storeSharedClass

public boolean storeSharedClass(java.lang.Class clazz,
                                int foundAtIndex)
Description copied from interface: SharedClassURLClasspathHelper
Store a class in the shared cache using the caller's URL classpath.

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 SharedClassURLClasspathHelper
Parameters:
clazz - Class. The class to store in the shared cache
foundAtIndex - int. The index in the caller's classpath where the class was loaded from (first entry is 0).
Returns:
boolean. True if the class was stored successfully, false otherwise.

storeSharedClass

public boolean storeSharedClass(java.lang.String partition,
                                java.lang.Class clazz,
                                int foundAtIndex)
Description copied from interface: SharedClassURLClasspathHelper
Store a class in the shared cache using the caller's URL classpath and with a user-defined partition.

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 SharedClassURLClasspathHelper
Parameters:
partition - String. User-defined partition if storing modified bytecode (see "Partitions" above). Passing null is equivalent of calling non-partition storeSharedClass call.
clazz - Class. The class to store in the shared cache
foundAtIndex - int. The index in the caller's classpath where the class was loaded from (first entry is 0).
Returns:
boolean. True if the class was stored successfully, false otherwise.

addClasspathEntry

public void addClasspathEntry(java.net.URL cpe)
Description copied from interface: SharedClassURLClasspathHelper
Update the helper's classpath by appending a URL (see "Usage" above).

Note: It is ESSENTIAL that the helper's classpath is kept up-to-date with the classloader's.

Specified by:
addClasspathEntry in interface SharedClassURLClasspathHelper
Parameters:
cpe - URL. The classpath entry to append to the classpath

confirmAllEntries

public void confirmAllEntries()
Description copied from interface: SharedClassURLClasspathHelper
Confirms all entries in the classpath.

This means that the classpath cannot be modified by setClasspath, but entries can still be added using addClasspathEntry (see "Efficient use..." above).

Specified by:
confirmAllEntries in interface SharedClassURLClasspathHelper

setClasspath

public void setClasspath(java.net.URL[] newClasspath)
                  throws CannotSetClasspathException
Description copied from interface: SharedClassURLClasspathHelper
Update the helper's classpath with a new classpath.

This function is useful for ClassLoaders that compute their classpath lazily. The initial classpath is passed to the constructor optimistically, but if the classloader discovers a change while reading an entry, it can update the classpath using this function.
Note: It is ESSENTIAL that the helper's classpath is kept up-to-date with the classloader's.

The classpath passed to this function must be exactly the same as the original classpath upto and including the rightmost entry that classes have been loaded from (the righmost "confirmed" entry).
Throws a CannotSetClasspathException if this is not the case (see "Modifying Classpaths" above).

Once the classpath has been updated, any indexes passed to storeSharedClass and returned from findSharedClass correspond to the new classpath.

Specified by:
setClasspath in interface SharedClassURLClasspathHelper
Parameters:
newClasspath - The new URL classpath array
Throws:
CannotSetClasspathException