com.sapportals.portal.prt.util

Class AutoClassLoader

java.lang.Object
  java.lang.ClassLoader
      java.security.SecureClassLoader
          com.sap.engine.frame.core.load.ReferencedLoader
              com.sapportals.portal.prt.util.AutoClassLoader

Deprecated. Note: Due to architectural chnages in the prt infrastructure, this class is no longer used for class loading. See http://help.sap.com for more details.

public class AutoClassLoader
extends com.sap.engine.frame.core.load.ReferencedLoader

The AutoClassLoader is the class loader implementation used by the Java iView Runtime. It differs from an ordinary class loader by the following features:

• Modification of class path by dynamical adding of jars and folders;
• Modified delegation pattern:
  • Blocking of parent delegation by resource prefices and thereby enforcement of a class/resource loading barrier to protect an inner name space;
  • Non-Standard delegation model for registration onto "up/sibling" slots in the class loader tree;

Notes:

• 6.0 modification for transitive loading pattern: This is mostly token computation in App Management. The loader however may now be set to assume transitive loading, in which case it will (again) rely on the class cache by the VM. Note "transitive loading" here means that this loader will never be called with a set of loading tokens that is a strict subset of its own delegation tokens.
• Concurrency fixes:
  • Still and unavoidably (except for expensive wait operation patterns) dead lock risks when having cyclic dependencies
  • Double check on local class load for cache content to avoid "duplicate class definition" problems
  • Extended dead-lock detection! See _deadLockTestAndRecovery! Can also handle cycles etc.
• Caching of (in particular) Jar entry lists to be able to respond quickly to class loading queries that are prone to fail.
• Shutdown functionality: The class loader can be told to shut down. If so, it will reject loading new class (resoures) and will drop all caches.
• 06/04: removed dead lock detection mechanism, since it is on the one hand not complete and on the other hand too expensive. Since external instrumentation should now about cycles anyway, it should be indicated to the load whether it may participate in a cyclic situation. If so, it must make sure it is the only one starting a load at a time.

Copyright (c) SAP Portals Europe GmbH 2001

Field Summary

Fields inherited from class com.sap.engine.frame.core.load.ReferencedLoader

CLASS_NOT_FOUND_EXCEPTION, classes, DEBUG_PROPERTY, debugMode, domain, globalDebugMode, parentLoader, useNegativeCache

Constructor Summary

AutoClassLoader(ClassLoader parentLoader)
Deprecated. Constructor

AutoClassLoader(ClassLoader parentLoader, Object token)
Deprecated. Constructor with registration to parent (if applicable)

AutoClassLoader(ClassLoader parentLoader, Object token, boolean transitive)
Deprecated. Constructor with registration to parent (if applicable) and transitivity setting.

AutoClassLoader(ClassLoader parentLoader, Object token, Object[] delegationTokens)
Deprecated. Constructor with registration to parent and definition of default tokens.

AutoClassLoader(ClassLoader parentLoader, Object token, Object[] delegationTokens, boolean transitive)
Deprecated. Constructor with registration to parent and definition of default tokens and transitivity setting.

AutoClassLoader(ClassLoader parentLoader, Object token, Object[] delegationTokens, boolean transitive, boolean cyclic)
Deprecated.

Method Summary

void	addClassProtectionPrefix(String prefix) Deprecated. Adds a class prefix to the list of protected class prefixes.
void	addFile(File file) Deprecated. Adds a url to the current classpath
void	addFolder(File folder) Deprecated. Add a Folder to the classpath
void	addJarsInFolder(File libFolder) Deprecated. Adds all jar files in the specfied folder to the classpath
void	addResourceProtectionPrefix(String prefix) Deprecated. Adds a resource prefix to the list of protected resource prefixes.
protected Package	definePackage(String name, Manifest man, URL url) Deprecated.
protected Class	findClass(String name) Deprecated. The crucial methods Finds a class.
protected Enumeration	findLocalResources(String fileName) Deprecated.
protected URL	findResource(String name) Deprecated. find a resource in the current class path
protected Enumeration	findResources(String name) Deprecated. Find the resources
protected URL	getLocalResource(String fileName) Deprecated.
protected InputStream	getLocalResourceAsStream(String fileName) Deprecated.
Vector	getPath() Deprecated. Returns a Vector containing the path of this loader.
Vector	getPaths(boolean withDependencies) Deprecated. Returns a Vector of path.
static Vector	getPaths(ClassLoader loader, Object[] tokens, boolean delegateToParent) Deprecated. Returns a Vector of path.
URL	getResource(Object[] tokens, String name, boolean delegateToParent) Deprecated. This version of getResource respects a propagation barrier, i.e. it will not delegate loading of specified resources or resources that have a specified name space.
URL	getResource(String name) Deprecated. This is the default signature of getResource
InputStream	getResourceAsStream(String name) Deprecated. This version of getResourceAsStream switches off the cache of resource bundles.
String[]	getResourceNames() Deprecated.
protected Class	loadClass(Object[] tokens, String name, boolean resolve, boolean delegateToParent) Deprecated. This version of loadClass respects a propagation barrier, i.e. it will not delegate loading of specified classes or classes that have a specified name space.
Class	loadClass(String name, boolean resolve) Deprecated. This is the default version of loadClass
protected Class	loadLocalClass(String className, String fileName) Deprecated.
protected byte[]	modifyByteCode(String className, byte[] bytes) Deprecated. This method exists only for api compatability. Execution of this method will return null value.
void	registerDelegationLoader(Object token, AutoClassLoader loader) Deprecated. Hierarchy handling: here child loaders may register by token.
void	release() Deprecated. Release.
void	setForceDelegationToParent(boolean p_b) Deprecated.
String	toString() Deprecated.
void	unregisterDelegationLoader(Object token) Deprecated. Hierarchy handling: here child loader may unregister by token.

Methods inherited from class com.sap.engine.frame.core.load.ReferencedLoader

clearNegativeCache, clearNegativeCacheInReferees, definePackage, findRefResources, findResourcesByReference, getAdditionalInfo, getInfo, getLoadedClasses, getName, getParentLoader, getParentName, getReferencesFrom, getReferencesTo, getRefResource, getRefResourceAsStream, getResourceAsStreamByReference, getResourceByReference, invalidate, loadClass, loadClassByReference, loadRefClass, negativeCacheContains, prepareForRemove, setDebugMode, setLockMonitor, setName, setUseNegativeCache

Methods inherited from class java.security.SecureClassLoader

defineClass, defineClass, getPermissions

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findLibrary, findLoadedClass, findSystemClass, getPackage, getPackages, getParent, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, resolveClass, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Constructor Detail

AutoClassLoader

public AutoClassLoader(ClassLoader parentLoader)

Deprecated.

Constructor

AutoClassLoader

public AutoClassLoader(ClassLoader parentLoader,
                       Object token)

Deprecated.

Constructor with registration to parent (if applicable)

AutoClassLoader

public AutoClassLoader(ClassLoader parentLoader,
                       Object token,
                       Object[] delegationTokens)

Deprecated.

Constructor with registration to parent and definition of default tokens.

AutoClassLoader

public AutoClassLoader(ClassLoader parentLoader,
                       Object token,
                       boolean transitive)

Deprecated.

Constructor with registration to parent (if applicable) and transitivity setting.

The transitivity flag indicates whether this loader is used in an assured transitive class loader set up. This means that it will never be called with a set of delegation tokens that is not a superset of its own tokens. This must be ensured by its using environment. If this cannot be ensured, this loader should not be set to be in a transitive setup.

AutoClassLoader

public AutoClassLoader(ClassLoader parentLoader,
                       Object token,
                       Object[] delegationTokens,
                       boolean transitive)

Deprecated.

Constructor with registration to parent and definition of default tokens and transitivity setting.

The transitivity flag indicates whether this loader is used in an assured transitive class loader set up. This means that it will never be called with a set of delegation tokens that is not a superset of its own tokens. This must be ensured by its using environment. If this cannot be ensured, this loader should not be set to be in a transitive setup.

AutoClassLoader

public AutoClassLoader(ClassLoader parentLoader,
                       Object token,
                       Object[] delegationTokens,
                       boolean transitive,
                       boolean cyclic)

Deprecated.

Method Detail

release

public void release()

Deprecated.

Release. To do here: unregister if registered before, release the class path, release the class cache... i.e.: shut down!

registerDelegationLoader

public void registerDelegationLoader(Object token,
                                     AutoClassLoader loader)

Deprecated.

Hierarchy handling: here child loaders may register by token.

unregisterDelegationLoader

public void unregisterDelegationLoader(Object token)

Deprecated.

Hierarchy handling: here child loader may unregister by token.

addFile

public void addFile(File file)

Deprecated.

Adds a url to the current classpath

addJarsInFolder

public void addJarsInFolder(File libFolder)

Deprecated.

Adds all jar files in the specfied folder to the classpath

addFolder

public void addFolder(File folder)

Deprecated.

Add a Folder to the classpath

addClassProtectionPrefix

public void addClassProtectionPrefix(String prefix)

Deprecated.

Adds a class prefix to the list of protected class prefixes.

addResourceProtectionPrefix

public void addResourceProtectionPrefix(String prefix)

Deprecated.

Adds a resource prefix to the list of protected resource prefixes.

getPaths

public Vector getPaths(boolean withDependencies)

Deprecated.

Returns a Vector of path.

getPaths

public static Vector getPaths(ClassLoader loader,
                              Object[] tokens,
                              boolean delegateToParent)

Deprecated.

Returns a Vector of path.

getPath

public Vector getPath()

Deprecated.

Returns a Vector containing the path of this loader.

toString

public String toString()

Deprecated.

Overrides:

toString in class com.sap.engine.frame.core.load.ReferencedLoader

findClass

protected Class findClass(String name)
                   throws ClassNotFoundException

Deprecated.

The crucial methods Finds a class. If it cannot be found, throw a classnotfound exception. to be called from a synchronized block! This implementation is to satisfy the inheritance promise. Internally we use the other "unsecure" and non-exception-throwing version.

Overrides:

findClass in class com.sap.engine.frame.core.load.ReferencedLoader

Throws:

ClassNotFoundException

definePackage

protected Package definePackage(String name,
                                Manifest man,
                                URL url)
                         throws IllegalArgumentException

Deprecated.

Throws:

IllegalArgumentException

loadClass

protected Class loadClass(Object[] tokens,
                          String name,
                          boolean resolve,
                          boolean delegateToParent)

Deprecated.

This version of loadClass respects a propagation barrier, i.e. it will not delegate loading of specified classes or classes that have a specified name space. Furthermore, it respects the delegation tokens mechanism. I.e. if it gets passed a list of delegation tokens, it will try to identify corresponding registered delegation loaders and give them a try after delegating up to the parent loader and looking locally.

Parameters:

tokens - the delegation tokens to be used for further delegation

name - the name of the class to be loaded

resolve - resolve (initialize) the class right after loading

delegateToParent - is this loader supposed to delegate to its parent, or simply look locally and by side delegation See ClassLoader for the general documentation.

loadClass

public Class loadClass(String name,
                       boolean resolve)
                throws ClassNotFoundException

Deprecated.

This is the default version of loadClass

Overrides:

loadClass in class com.sap.engine.frame.core.load.ReferencedLoader

Throws:

ClassNotFoundException

findResource

protected URL findResource(String name)

Deprecated.

find a resource in the current class path

Overrides:

findResource in class ClassLoader

findResources

protected Enumeration findResources(String name)
                             throws IOException

Deprecated.

Find the resources

Overrides:

findResources in class com.sap.engine.frame.core.load.ReferencedLoader

Throws:

IOException

getResourceAsStream

public InputStream getResourceAsStream(String name)

Deprecated.

This version of getResourceAsStream switches off the cache of resource bundles. Switching off the cache is mandatory to allow hot deployment of portal applications including resource bundles in their JARs. This is a workaround recommended by SUN; please check: http://developer.java.sun.com/developer/bugParade/bugs/4386865.html

Overrides:

getResourceAsStream in class com.sap.engine.frame.core.load.ReferencedLoader

getResource

public URL getResource(Object[] tokens,
                       String name,
                       boolean delegateToParent)

Deprecated.

This version of getResource respects a propagation barrier, i.e. it will not delegate loading of specified resources or resources that have a specified name space. Furthermore, it respects the delegation tokens mechanism. I.e. if it gets passed a list of delegation tokens, it will try to identify corresponding registered delegation loaders and give them a try after delegating up to the parent loader and looking locally See ClassLoader for the general documentation.

getResource

public URL getResource(String name)

Deprecated.

This is the default signature of getResource

Overrides:

getResource in class com.sap.engine.frame.core.load.ReferencedLoader

loadLocalClass

protected Class loadLocalClass(String className,
                               String fileName)
                        throws ClassNotFoundException

Deprecated.

Specified by:

loadLocalClass in class com.sap.engine.frame.core.load.ReferencedLoader

Throws:

ClassNotFoundException

getLocalResource

protected URL getLocalResource(String fileName)

Deprecated.

Specified by:

getLocalResource in class com.sap.engine.frame.core.load.ReferencedLoader

findLocalResources

protected Enumeration findLocalResources(String fileName)
                                  throws IOException

Deprecated.

Specified by:

findLocalResources in class com.sap.engine.frame.core.load.ReferencedLoader

Throws:

IOException

getLocalResourceAsStream

protected InputStream getLocalResourceAsStream(String fileName)

Deprecated.

Specified by:

getLocalResourceAsStream in class com.sap.engine.frame.core.load.ReferencedLoader

getResourceNames

public String[] getResourceNames()

Deprecated.

Specified by:

getResourceNames in class com.sap.engine.frame.core.load.ReferencedLoader

setForceDelegationToParent

public void setForceDelegationToParent(boolean p_b)

Deprecated.

Parameters:

p_b -

modifyByteCode

protected byte[] modifyByteCode(String className,
                                byte[] bytes)

Deprecated. This method exists only for api compatability. Execution of this method will return null value.

Access Rights

This class can be accessed from:

SC	DC	Public Part	ACH
[sap.com] EP-BASIS-API	[sap.com] tc/epbc/prt/lib/api	api	EP-PIN
[sap.com] EP-BASIS-API	[sap.com] tc/epbc/prt/api	api	EP-PIN