public abstract class WebappClassLoaderBase extends URLClassLoader implements Lifecycle, InstrumentableClassLoader, WebappProperties
This class loader is a full reimplementation of the
URLClassLoader
from the JDK. It is designed to be fully
compatible with a normal URLClassLoader
, although its internal
behavior may be completely different.
IMPLEMENTATION NOTE - By default, this class loader follows
the delegation model required by the specification. The system class
loader will be queried first, then the local repositories, and only then
delegation to the parent class loader will occur. This allows the web
application to override any shared class except the classes from J2SE.
Special handling is provided from the JAXP XML parser interfaces, the JNDI
interfaces, and the classes from the servlet API, which are never loaded
from the webapp repositories. The delegate
property
allows an application to modify this behavior to move the parent class loader
ahead of the local repositories.
IMPLEMENTATION NOTE - Due to limitations in Jasper compilation technology, any repository which contains classes from the servlet API will be ignored by the class loader.
IMPLEMENTATION NOTE - The class loader generates source URLs which include the full JAR URL when a class is loaded from a JAR file, which allows setting security permission at the class level, even when a class is contained inside a JAR.
IMPLEMENTATION NOTE - Local repositories are searched in the order they are added via the initial constructor.
IMPLEMENTATION NOTE - No check for sealing violations or security is made unless a security manager is present.
IMPLEMENTATION NOTE - As of 8.0, this class
loader implements InstrumentableClassLoader
, permitting web
application classes to instrument other classes in the same web
application. It does not permit instrumentation of system or container
classes or classes in other web apps.
Modifier and Type | Class and Description |
---|---|
protected class |
WebappClassLoaderBase.PrivilegedFindClassByName |
protected static class |
WebappClassLoaderBase.PrivilegedGetClassLoader |
Lifecycle.SingleUse
Modifier and Type | Field and Description |
---|---|
protected boolean |
delegate
Should this class loader delegate to the parent class loader
before searching its own repositories (i.e. the
usual Java2 delegation model)?
|
protected HashMap<String,PermissionCollection> |
loaderPC
The PermissionCollection for each CodeSource for a web
application context.
|
protected ClassLoader |
parent
The parent class loader.
|
protected ArrayList<Permission> |
permissionList
A list of read File and Jndi Permission's required if this loader
is for a web application context.
|
protected Map<String,ResourceEntry> |
resourceEntries
The cache of ResourceEntry for classes and resources we have loaded,
keyed by resource path, not binary name.
|
protected WebResourceRoot |
resources
Associated web resources for this webapp.
|
protected SecurityManager |
securityManager
Instance of the SecurityManager installed.
|
protected static StringManager |
sm
The string manager for this package.
|
AFTER_DESTROY_EVENT, AFTER_INIT_EVENT, AFTER_START_EVENT, AFTER_STOP_EVENT, BEFORE_DESTROY_EVENT, BEFORE_INIT_EVENT, BEFORE_START_EVENT, BEFORE_STOP_EVENT, CONFIGURE_START_EVENT, CONFIGURE_STOP_EVENT, PERIODIC_EVENT, START_EVENT, STOP_EVENT
Modifier | Constructor and Description |
---|---|
protected |
WebappClassLoaderBase()
Construct a new ClassLoader with no defined repositories and no
parent ClassLoader.
|
protected |
WebappClassLoaderBase(ClassLoader parent)
Construct a new ClassLoader with no defined repositories and the given
parent ClassLoader.
|
Modifier and Type | Method and Description |
---|---|
void |
addLifecycleListener(LifecycleListener listener)
Add a lifecycle event listener to this component.
|
void |
addTransformer(ClassFileTransformer transformer)
Adds the specified class file transformer to this class loader.
|
protected void |
addURL(URL url) |
protected void |
checkStateForClassLoading(String className) |
protected void |
checkStateForResourceLoading(String resource) |
protected void |
clearReferences()
Clear references.
|
protected void |
copyStateWithoutTransformers(WebappClassLoaderBase base) |
void |
destroy()
Prepare to discard the object.
|
protected Class<?> |
doDefineClass(String name,
byte[] b,
int off,
int len,
ProtectionDomain protectionDomain) |
protected boolean |
filter(String name,
boolean isClassName)
Filter classes.
|
Class<?> |
findClass(String name)
Find the specified class in our local repositories, if possible.
|
protected Class<?> |
findClassInternal(String name)
Find specified class in local repositories.
|
LifecycleListener[] |
findLifecycleListeners()
Get the lifecycle listeners associated with this lifecycle.
|
protected Class<?> |
findLoadedClass0(String name)
Finds the class with the given name if it has previously been
loaded and cached by this class loader, and return the Class object.
|
URL |
findResource(String name)
Find the specified resource in our local repository, and return a
URL referring to it, or null if this resource
cannot be found. |
Enumeration<URL> |
findResources(String name)
Return an enumeration of
URLs representing all of the
resources with the given name. |
boolean |
getClearReferencesHttpClientKeepAliveThread() |
boolean |
getClearReferencesLogFactoryRelease() |
boolean |
getClearReferencesRmiTargets() |
boolean |
getClearReferencesStopThreads() |
boolean |
getClearReferencesStopTimerThreads() |
String |
getContextName() |
boolean |
getDelegate()
Return the "delegate first" flag for this class loader.
|
String |
getHostName()
Returns a name for the logging system to use for the Host where the
web application, if any, associated with the class loader is deployed.
|
protected ClassLoader |
getJavaseClassLoader() |
protected PermissionCollection |
getPermissions(CodeSource codeSource)
Get the Permissions for a CodeSource.
|
URL |
getResource(String name)
Find the resource with the given name.
|
InputStream |
getResourceAsStream(String name)
Find the resource with the given name, and return an input stream
that can be used for reading it.
|
WebResourceRoot |
getResources() |
String |
getServiceName()
Returns a name for the logging system to use for the Service where the
Host, if any, associated with the class loader is deployed.
|
LifecycleState |
getState()
Obtain the current state of the source component.
|
String |
getStateName()
Obtain a textual representation of the current component state.
|
URL[] |
getURLs()
Note that list of URLs returned by this method may not be complete.
|
String |
getWebappName()
Returns a name for the logging system to use for the web application, if
any, associated with the class loader.
|
void |
init()
Prepare the component for starting.
|
protected boolean |
isPackageSealed(String name,
Manifest man)
Returns true if the specified package name is sealed according to the
given manifest.
|
Class<?> |
loadClass(String name)
Load the class with the specified name.
|
Class<?> |
loadClass(String name,
boolean resolve)
Load the class with the specified name, searching using the following
algorithm until it finds and returns the class.
|
boolean |
modified()
Have one or more classes or resources been modified so that a reload
is appropriate?
|
protected void |
refreshPolicy()
Refresh the system policy file, to pick up eventual changes.
|
void |
removeLifecycleListener(LifecycleListener listener)
Remove a lifecycle event listener from this component.
|
void |
removeTransformer(ClassFileTransformer transformer)
Removes the specified class file transformer from this class loader.
|
void |
setClearReferencesHttpClientKeepAliveThread(boolean clearReferencesHttpClientKeepAliveThread)
Set the clearReferencesHttpClientKeepAliveThread feature for this
Context.
|
void |
setClearReferencesLogFactoryRelease(boolean clearReferencesLogFactoryRelease)
Set the clearReferencesLogFactoryRelease feature for this Context.
|
void |
setClearReferencesRmiTargets(boolean clearReferencesRmiTargets) |
void |
setClearReferencesStopThreads(boolean clearReferencesStopThreads)
Set the clearReferencesStopThreads feature for this Context.
|
void |
setClearReferencesStopTimerThreads(boolean clearReferencesStopTimerThreads)
Set the clearReferencesStopTimerThreads feature for this Context.
|
void |
setDelegate(boolean delegate)
Set the "delegate first" flag for this class loader.
|
protected void |
setJavaseClassLoader(ClassLoader classLoader) |
void |
setResources(WebResourceRoot resources)
Set associated resources.
|
void |
start()
Start the class loader.
|
void |
stop()
Stop the class loader.
|
String |
toString() |
close, definePackage, newInstance, newInstance
defineClass, defineClass
clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findLibrary, findLoadedClass, findSystemClass, getClassLoadingLock, getPackage, getPackages, getParent, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, registerAsParallelCapable, resolveClass, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
copyWithoutTransformers
protected static final StringManager sm
protected WebResourceRoot resources
protected final Map<String,ResourceEntry> resourceEntries
protected boolean delegate
false
,
this class loader will search its own repositories first, and
delegate to the parent only if the class or resource is not
found locally. Note that the default, false
, is
the behavior called for by the servlet specification.protected final ArrayList<Permission> permissionList
protected final HashMap<String,PermissionCollection> loaderPC
protected final SecurityManager securityManager
protected final ClassLoader parent
protected WebappClassLoaderBase()
protected WebappClassLoaderBase(ClassLoader parent)
Method is used via reflection -
see WebappLoader.createClassLoader()
parent
- Our parent class loaderpublic WebResourceRoot getResources()
public void setResources(WebResourceRoot resources)
resources
- the resources from which the classloader will
load the classespublic String getContextName()
public boolean getDelegate()
true
if the class lookup will delegate to
the parent first. The default in Tomcat is false
.public void setDelegate(boolean delegate)
false
(the default),
this class loader will search its own repositories first, and
delegate to the parent only if the class or resource is not
found locally, as per the servlet specification.delegate
- The new "delegate first" flagpublic boolean getClearReferencesRmiTargets()
public void setClearReferencesRmiTargets(boolean clearReferencesRmiTargets)
public boolean getClearReferencesStopThreads()
public void setClearReferencesStopThreads(boolean clearReferencesStopThreads)
clearReferencesStopThreads
- The new flag valuepublic boolean getClearReferencesStopTimerThreads()
public void setClearReferencesStopTimerThreads(boolean clearReferencesStopTimerThreads)
clearReferencesStopTimerThreads
- The new flag valuepublic boolean getClearReferencesLogFactoryRelease()
public void setClearReferencesLogFactoryRelease(boolean clearReferencesLogFactoryRelease)
clearReferencesLogFactoryRelease
- The new flag valuepublic boolean getClearReferencesHttpClientKeepAliveThread()
public void setClearReferencesHttpClientKeepAliveThread(boolean clearReferencesHttpClientKeepAliveThread)
clearReferencesHttpClientKeepAliveThread
- The new flag valuepublic void addTransformer(ClassFileTransformer transformer)
addTransformer
in interface InstrumentableClassLoader
transformer
- The transformer to add to the class loaderpublic void removeTransformer(ClassFileTransformer transformer)
removeTransformer
in interface InstrumentableClassLoader
transformer
- The transformer to removeprotected void copyStateWithoutTransformers(WebappClassLoaderBase base)
public boolean modified()
true
if there's been a modificationprotected final Class<?> doDefineClass(String name, byte[] b, int off, int len, ProtectionDomain protectionDomain)
public Class<?> findClass(String name) throws ClassNotFoundException
ClassNotFoundException
.findClass
in class URLClassLoader
name
- The binary name of the class to be loadedClassNotFoundException
- if the class was not foundpublic URL findResource(String name)
URL
referring to it, or null
if this resource
cannot be found.findResource
in class URLClassLoader
name
- Name of the resource to be foundpublic Enumeration<URL> findResources(String name) throws IOException
URLs
representing all of the
resources with the given name. If no resources with this name are
found, return an empty enumeration.findResources
in class URLClassLoader
name
- Name of the resources to be foundIOException
- if an input/output error occurspublic URL getResource(String name)
null
.
This method searches according to the following algorithm, returning
as soon as it finds the appropriate URL. If the resource cannot be
found, returns null
.
delegate
property is set to true
,
call the getResource()
method of the parent class
loader, if any.findResource()
to find this resource in our
locally defined repositories.getResource()
method of the parent class
loader, if any.getResource
in class ClassLoader
name
- Name of the resource to return a URL forpublic InputStream getResourceAsStream(String name)
getResource()
, after checking to see if the resource
data has been previously cached. If the resource cannot be found,
return null
.getResourceAsStream
in class URLClassLoader
name
- Name of the resource to return an input stream forpublic Class<?> loadClass(String name) throws ClassNotFoundException
loadClass(String, boolean)
with false
as the second argument.loadClass
in class ClassLoader
name
- The binary name of the class to be loadedClassNotFoundException
- if the class was not foundpublic Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException
ClassNotFoundException
.
findLoadedClass(String)
to check if the
class has already been loaded. If it has, the same
Class
object is returned.delegate
property is set to true
,
call the loadClass()
method of the parent class
loader, if any.findClass()
to find this class in our locally
defined repositories.loadClass()
method of our parent
class loader, if any.resolve
flag is true
, this method will then
call resolveClass(Class)
on the resulting Class object.loadClass
in class ClassLoader
name
- The binary name of the class to be loadedresolve
- If true
then resolve the classClassNotFoundException
- if the class was not foundprotected void checkStateForClassLoading(String className) throws ClassNotFoundException
ClassNotFoundException
protected void checkStateForResourceLoading(String resource) throws IllegalStateException
IllegalStateException
protected PermissionCollection getPermissions(CodeSource codeSource)
getPermissions
in class URLClassLoader
codeSource
- where the code was loaded frompublic URL[] getURLs()
Note that list of URLs returned by this method may not be complete. The
web application class loader accesses class loader resources via the
WebResourceRoot
which supports the arbitrary mapping of
additional files, directories and contents of JAR files under
WEB-INF/classes. Any such resources will not be included in the URLs
returned here.
getURLs
in class URLClassLoader
public void addLifecycleListener(LifecycleListener listener)
addLifecycleListener
in interface Lifecycle
listener
- The listener to addpublic LifecycleListener[] findLifecycleListeners()
findLifecycleListeners
in interface Lifecycle
public void removeLifecycleListener(LifecycleListener listener)
removeLifecycleListener
in interface Lifecycle
listener
- The listener to removepublic LifecycleState getState()
public String getStateName()
Lifecycle.getState()
.getStateName
in interface Lifecycle
public void init()
Lifecycle
LifecycleEvent
s will be fired in the following order:
public void start() throws LifecycleException
start
in interface Lifecycle
LifecycleException
- if a lifecycle error occurspublic void stop() throws LifecycleException
stop
in interface Lifecycle
LifecycleException
- if a lifecycle error occurspublic void destroy()
Lifecycle
LifecycleEvent
s will
be fired in the following order:
protected ClassLoader getJavaseClassLoader()
protected void setJavaseClassLoader(ClassLoader classLoader)
protected void clearReferences()
protected Class<?> findClassInternal(String name)
name
- The binary name of the class to be loadedprotected boolean isPackageSealed(String name, Manifest man)
name
- Path name to checkman
- Associated manifesttrue
if the manifest associated says it is sealedprotected Class<?> findLoadedClass0(String name)
null
.name
- The binary name of the resource to returnprotected void refreshPolicy()
protected boolean filter(String name, boolean isClassName)
name
- class nameisClassName
- true
if name is a class name,
false
if name is a resource nametrue
if the class should be filteredprotected void addURL(URL url)
addURL
in class URLClassLoader
public String getWebappName()
WebappProperties
getWebappName
in interface WebappProperties
public String getHostName()
WebappProperties
getHostName
in interface WebappProperties
public String getServiceName()
WebappProperties
getServiceName
in interface WebappProperties
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