org.apache.catalina.loader

Class WebappLoader

java.lang.Object

org.apache.catalina.util.LifecycleBase

org.apache.catalina.util.LifecycleMBeanBase

org.apache.catalina.loader.WebappLoader

All Implemented Interfaces:

PropertyChangeListener, EventListener, MBeanRegistration, JmxEnabled, Lifecycle, Loader

public class WebappLoader
extends LifecycleMBeanBase
implements Loader, PropertyChangeListener

Classloader implementation which is specialized for handling web applications in the most efficient way, while being Catalina aware (all accesses to resources are made through WebResourceRoot). This class loader supports detection of modified Java classes, which can be used to implement auto-reload support.

This class loader is configured via the Resources children of its Context prior to calling start(). When a new class is required, these Resources will be consulted first to locate the class. If it is not present, the system class loader will be used instead.

Author:

Craig R. McClanahan, Remy Maucherat

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.catalina.Lifecycle

Lifecycle.SingleUse

Field Summary

Fields

Modifier and Type	Field and Description
protected static StringManager	sm The string manager for this package.
protected PropertyChangeSupport	support The property change support for this component.

Fields inherited from class org.apache.catalina.util.LifecycleMBeanBase

mserver

Fields inherited from interface org.apache.catalina.Lifecycle

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

Constructor Summary

Constructors

Constructor and Description
WebappLoader() Construct a new WebappLoader with no defined parent class loader (so that the actual parent will be the system class loader).
WebappLoader(ClassLoader parent) Construct a new WebappLoader with the specified class loader to be defined as the parent of the ClassLoader we ultimately create.

Method Summary

Modifier and Type	Method and Description
void	addPropertyChangeListener(PropertyChangeListener listener) Add a property change listener to this component.
void	backgroundProcess() Execute a periodic task, such as reloading, etc.
ClassLoader	getClassLoader() Return the Java class loader to be used by this Container.
String	getClasspath() Classpath, as set in org.apache.catalina.jsp_classpath context property
Context	getContext()
boolean	getDelegate() Return the "follow standard delegation model" flag used to configure our ClassLoader.
protected String	getDomainInternal() Method implemented by sub-classes to identify the domain in which MBeans should be registered.
String	getLoaderClass()
String[]	getLoaderRepositories()
String	getLoaderRepositoriesString()
protected String	getObjectNameKeyProperties() Allow sub-classes to specify the key properties component of the ObjectName that will be used to register this component.
boolean	getReloadable() Return the reloadable flag for this Loader.
boolean	modified() Has the internal repository associated with this Loader been modified, such that the loaded classes should be reloaded?
void	propertyChange(PropertyChangeEvent event) Process property change events from our associated Context.
void	removePropertyChangeListener(PropertyChangeListener listener) Remove a property change listener from this component.
void	setContext(Context context) Set the Context with which this Loader has been associated.
void	setDelegate(boolean delegate) Set the "follow standard delegation model" flag used to configure our ClassLoader.
void	setLoaderClass(String loaderClass) Set the ClassLoader class name.
void	setReloadable(boolean reloadable) Set the reloadable flag for this Loader.
protected void	startInternal() Start associated ClassLoader and implement the requirements of LifecycleBase.startInternal().
protected void	stopInternal() Stop associated ClassLoader and implement the requirements of LifecycleBase.stopInternal().
String	toString() Return a String representation of this component.

Methods inherited from class org.apache.catalina.util.LifecycleMBeanBase

destroyInternal, getDomain, getObjectName, initInternal, postDeregister, postRegister, preDeregister, preRegister, register, setDomain, unregister

Methods inherited from class org.apache.catalina.util.LifecycleBase

addLifecycleListener, destroy, findLifecycleListeners, fireLifecycleEvent, getState, getStateName, init, removeLifecycleListener, setState, setState, start, stop

Methods inherited from class java.lang.Object

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

Field Detail

sm

protected static final StringManager sm

The string manager for this package.

support

protected final PropertyChangeSupport support

The property change support for this component.

Constructor Detail

WebappLoader

public WebappLoader()

Construct a new WebappLoader with no defined parent class loader (so that the actual parent will be the system class loader).

WebappLoader

public WebappLoader(ClassLoader parent)

Construct a new WebappLoader with the specified class loader to be defined as the parent of the ClassLoader we ultimately create.

Parameters:

parent - The parent class loader

Method Detail

getClassLoader

public ClassLoader getClassLoader()

Return the Java class loader to be used by this Container.

Specified by:

getClassLoader in interface Loader

Returns:

the Java class loader to be used by this Container.

getContext

public Context getContext()

Specified by:

getContext in interface Loader

Returns:

the Context with which this Loader has been associated.

setContext

public void setContext(Context context)

Description copied from interface: Loader

Set the Context with which this Loader has been associated.

Specified by:

setContext in interface Loader

Parameters:

context - The associated Context

getDelegate

public boolean getDelegate()

Return the "follow standard delegation model" flag used to configure our ClassLoader.

Specified by:

getDelegate in interface Loader

Returns:

the "follow standard delegation model" flag used to configure our ClassLoader.

setDelegate

public void setDelegate(boolean delegate)

Set the "follow standard delegation model" flag used to configure our ClassLoader.

Specified by:

setDelegate in interface Loader

Parameters:

delegate - The new flag

getLoaderClass

public String getLoaderClass()

Returns:

the ClassLoader class name.

setLoaderClass

public void setLoaderClass(String loaderClass)

Set the ClassLoader class name.

Parameters:

loaderClass - The new ClassLoader class name

getReloadable

public boolean getReloadable()

Return the reloadable flag for this Loader.

Specified by:

getReloadable in interface Loader

Returns:

the reloadable flag for this Loader.

setReloadable

public void setReloadable(boolean reloadable)

Set the reloadable flag for this Loader.

Specified by:

setReloadable in interface Loader

Parameters:

reloadable - The new reloadable flag

addPropertyChangeListener

public void addPropertyChangeListener(PropertyChangeListener listener)

Add a property change listener to this component.

Specified by:

addPropertyChangeListener in interface Loader

Parameters:

listener - The listener to add

backgroundProcess

public void backgroundProcess()

Execute a periodic task, such as reloading, etc. This method will be invoked inside the classloading context of this container. Unexpected throwables will be caught and logged.

Specified by:

backgroundProcess in interface Loader

getLoaderRepositories

public String[] getLoaderRepositories()

getLoaderRepositoriesString

public String getLoaderRepositoriesString()

getClasspath

public String getClasspath()

Classpath, as set in org.apache.catalina.jsp_classpath context property

Returns:

The classpath

modified

public boolean modified()

Has the internal repository associated with this Loader been modified, such that the loaded classes should be reloaded?

Specified by:

modified in interface Loader

Returns:

true when the repository has been modified, false otherwise

removePropertyChangeListener

public void removePropertyChangeListener(PropertyChangeListener listener)

Remove a property change listener from this component.

Specified by:

removePropertyChangeListener in interface Loader

Parameters:

listener - The listener to remove

toString

public String toString()

Return a String representation of this component.

Overrides:

toString in class Object

startInternal

protected void startInternal()
                      throws LifecycleException

Start associated ClassLoader and implement the requirements of LifecycleBase.startInternal().

Specified by:

startInternal in class LifecycleBase

Throws:

LifecycleException - if this component detects a fatal error that prevents this component from being used

stopInternal

protected void stopInternal()
                     throws LifecycleException

Stop associated ClassLoader and implement the requirements of LifecycleBase.stopInternal().

Specified by:

stopInternal in class LifecycleBase

Throws:

LifecycleException - if this component detects a fatal error that prevents this component from being used

propertyChange

public void propertyChange(PropertyChangeEvent event)

Process property change events from our associated Context.

Specified by:

propertyChange in interface PropertyChangeListener

Parameters:

event - The property change event that has occurred

getDomainInternal

protected String getDomainInternal()

Description copied from class: LifecycleMBeanBase

Method implemented by sub-classes to identify the domain in which MBeans should be registered.

Specified by:

getDomainInternal in class LifecycleMBeanBase

Returns:

The name of the domain to use to register MBeans.

getObjectNameKeyProperties

protected String getObjectNameKeyProperties()

Description copied from class: LifecycleMBeanBase

Allow sub-classes to specify the key properties component of the ObjectName that will be used to register this component.

Specified by:

getObjectNameKeyProperties in class LifecycleMBeanBase

Returns:

The string representation of the key properties component of the desired ObjectName