org.apache.catalina
Interface Container
public
interface
Container
A
Container is an object that can execute requests received from
a client, and return responses based on those requests. A Container may
optionally support a pipeline of Valves that process the request in an
order configured at runtime, by implementing the
Pipeline interface
as well.
Containers will exist at several conceptual levels within Catalina. The
following examples represent common cases:
- Engine - Representation of the entire Catalina servlet engine,
most likely containing one or more subcontainers that are either Host
or Context implementations, or other custom groups.
- Host - Representation of a virtual host containing a number
of Contexts.
- Context - Representation of a single ServletContext, which will
typically contain one or more Wrappers for the supported servlets.
- Wrapper - Representation of an individual servlet definition
(which may support multiple servlet instances if the servlet itself
implements SingleThreadModel).
A given deployment of Catalina need not include Containers at all of the
levels described above. For example, an administration application
embedded within a network device (such as a router) might only contain
a single Context and a few Wrappers, or even a single Wrapper if the
application is relatively small. Therefore, Container implementations
need to be designed so that they will operate correctly in the absence
of parent Containers in a given deployment.
A Container may also be associated with a number of support components
that provide functionality which might be shared (by attaching it to a
parent Container) or individually customized. The following support
components are currently recognized:
- Loader - Class loader to use for integrating new Java classes
for this Container into the JVM in which Catalina is running.
- Logger - Implementation of the
log()
method
signatures of the ServletContext
interface.
- Manager - Manager for the pool of Sessions associated with
this Container.
- Realm - Read-only interface to a security domain, for
authenticating user identities and their corresponding roles.
- Resources - JNDI directory context enabling access to static
resources, enabling custom linkages to existing server components when
Catalina is embedded in a larger server.
Version: $Revision: 467222 $ $Date: 2006-10-24 05:17:11 +0200 (Tue, 24 Oct 2006) $
Author: Craig R. McClanahan Remy Maucherat
Field Summary |
static String | ADD_CHILD_EVENT
The ContainerEvent event type sent when a child container is added
by addChild() . |
static String | ADD_MAPPER_EVENT
The ContainerEvent event type sent when a Mapper is added
by addMapper() . |
static String | ADD_VALVE_EVENT
The ContainerEvent event type sent when a valve is added
by addValve() , if this Container supports pipelines. |
static String | REMOVE_CHILD_EVENT
The ContainerEvent event type sent when a child container is removed
by removeChild() . |
static String | REMOVE_MAPPER_EVENT
The ContainerEvent event type sent when a Mapper is removed
by removeMapper() . |
static String | REMOVE_VALVE_EVENT
The ContainerEvent event type sent when a valve is removed
by removeValve() , if this Container supports pipelines. |
Method Summary |
void | addChild(Container child)
Add a new child Container to those associated with this Container,
if supported. |
void | addContainerListener(ContainerListener listener)
Add a container event listener to this component.
|
void | addPropertyChangeListener(PropertyChangeListener listener)
Add a property change listener to this component.
|
void | backgroundProcess()
Execute a periodic task, such as reloading, etc. |
Container | findChild(String name)
Return the child Container, associated with this Container, with
the specified name (if any); otherwise, return null
|
Container[] | findChildren()
Return the set of children Containers associated with this Container.
|
ContainerListener[] | findContainerListeners()
Return the set of container listeners associated with this Container.
|
int | getBackgroundProcessorDelay()
Get the delay between the invocation of the backgroundProcess method on
this container and its children. |
Cluster | getCluster()
Return the Cluster with which this Container is associated. |
String | getInfo()
Return descriptive information about this Container implementation and
the corresponding version number, in the format
<description>/<version> . |
Loader | getLoader()
Return the Loader with which this Container is associated. |
Log | getLogger()
Return the Logger with which this Container is associated. |
Manager | getManager()
Return the Manager with which this Container is associated. |
Object | getMappingObject()
Return an object which may be utilized for mapping to this component. |
String | getName()
Return a name string (suitable for use by humans) that describes this
Container. |
String | getObjectName()
Return the JMX name associated with this container. |
Container | getParent()
Return the Container for which this Container is a child, if there is
one. |
ClassLoader | getParentClassLoader()
Return the parent class loader (if any) for web applications. |
Pipeline | getPipeline()
Return the Pipeline object that manages the Valves associated with
this Container. |
Realm | getRealm()
Return the Realm with which this Container is associated. |
DirContext | getResources()
Return the Resources with which this Container is associated. |
void | invoke(Request request, Response response)
Process the specified Request, and generate the corresponding Response,
according to the design of this particular Container.
|
void | removeChild(Container child)
Remove an existing child Container from association with this parent
Container.
|
void | removeContainerListener(ContainerListener listener)
Remove a container event listener from this component.
|
void | removePropertyChangeListener(PropertyChangeListener listener)
Remove a property change listener from this component.
|
void | setBackgroundProcessorDelay(int delay)
Set the delay between the invocation of the execute method on this
container and its children.
|
void | setCluster(Cluster cluster)
Set the Cluster with which this Container is associated.
|
void | setLoader(Loader loader)
Set the Loader with which this Container is associated.
|
void | setManager(Manager manager)
Set the Manager with which this Container is associated.
|
void | setName(String name)
Set a name string (suitable for use by humans) that describes this
Container. |
void | setParent(Container container)
Set the parent Container to which this Container is being added as a
child. |
void | setParentClassLoader(ClassLoader parent)
Set the parent class loader (if any) for web applications.
|
void | setRealm(Realm realm)
Set the Realm with which this Container is associated.
|
void | setResources(DirContext resources)
Set the Resources object with which this Container is associated.
|
public static final String ADD_CHILD_EVENT
The ContainerEvent event type sent when a child container is added
by addChild()
.
public static final String ADD_MAPPER_EVENT
The ContainerEvent event type sent when a Mapper is added
by addMapper()
.
public static final String ADD_VALVE_EVENT
The ContainerEvent event type sent when a valve is added
by addValve()
, if this Container supports pipelines.
public static final String REMOVE_CHILD_EVENT
The ContainerEvent event type sent when a child container is removed
by removeChild()
.
public static final String REMOVE_MAPPER_EVENT
The ContainerEvent event type sent when a Mapper is removed
by removeMapper()
.
public static final String REMOVE_VALVE_EVENT
The ContainerEvent event type sent when a valve is removed
by removeValve()
, if this Container supports pipelines.
Add a new child Container to those associated with this Container,
if supported. Prior to adding this Container to the set of children,
the child's
setParent()
method must be called, with this
Container as an argument. This method may thrown an
IllegalArgumentException
if this Container chooses not
to be attached to the specified Container, in which case it is not added
Parameters: child New child Container to be added
Throws: IllegalArgumentException if this exception is thrown by
the setParent()
method of the child Container IllegalArgumentException if the new child does not have
a name unique from that of existing children of this Container IllegalStateException if this Container does not support
child Containers
Add a container event listener to this component.
Parameters: listener The listener to add
public void addPropertyChangeListener(PropertyChangeListener listener)
Add a property change listener to this component.
Parameters: listener The listener to add
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.
Return the child Container, associated with this Container, with
the specified name (if any); otherwise, return
null
Parameters: name Name of the child Container to be retrieved
Return the set of children Containers associated with this Container.
If this Container has no children, a zero-length array is returned.
Return the set of container listeners associated with this Container.
If this Container has no registered container listeners, a zero-length
array is returned.
public int getBackgroundProcessorDelay()
Get the delay between the invocation of the backgroundProcess method on
this container and its children. Child containers will not be invoked
if their delay value is not negative (which would mean they are using
their own thread). Setting this to a positive value will cause
a thread to be spawn. After waiting the specified amount of time,
the thread will invoke the executePeriodic method on this container
and all its children.
Return the Cluster with which this Container is associated. If there is
no associated Cluster, return the Cluster associated with our parent
Container (if any); otherwise return null
.
public String getInfo()
Return descriptive information about this Container implementation and
the corresponding version number, in the format
<description>/<version>
.
Return the Loader with which this Container is associated. If there is
no associated Loader, return the Loader associated with our parent
Container (if any); otherwise, return null
.
Return the Logger with which this Container is associated. If there is
no associated Logger, return the Logger associated with our parent
Container (if any); otherwise return null
.
Return the Manager with which this Container is associated. If there is
no associated Manager, return the Manager associated with our parent
Container (if any); otherwise return null
.
public Object getMappingObject()
Return an object which may be utilized for mapping to this component.
public String getName()
Return a name string (suitable for use by humans) that describes this
Container. Within the set of child containers belonging to a particular
parent, Container names must be unique.
public String getObjectName()
Return the JMX name associated with this container.
Return the Container for which this Container is a child, if there is
one. If there is no defined parent, return null
.
public ClassLoader getParentClassLoader()
Return the parent class loader (if any) for web applications.
Return the Pipeline object that manages the Valves associated with
this Container.
Return the Realm with which this Container is associated. If there is
no associated Realm, return the Realm associated with our parent
Container (if any); otherwise return null
.
public DirContext getResources()
Return the Resources with which this Container is associated. If there
is no associated Resources object, return the Resources associated with
our parent Container (if any); otherwise return null
.
Process the specified Request, and generate the corresponding Response,
according to the design of this particular Container.
Parameters: request Request to be processed response Response to be produced
Throws: IOException if an input/output error occurred while
processing ServletException if a ServletException was thrown
while processing this request
Remove an existing child Container from association with this parent
Container.
Parameters: child Existing child Container to be removed
Remove a container event listener from this component.
Parameters: listener The listener to remove
public void removePropertyChangeListener(PropertyChangeListener listener)
Remove a property change listener from this component.
Parameters: listener The listener to remove
public void setBackgroundProcessorDelay(int delay)
Set the delay between the invocation of the execute method on this
container and its children.
Parameters: delay The delay in seconds between the invocation of
backgroundProcess methods
public void setCluster(
Cluster cluster)
Set the Cluster with which this Container is associated.
Parameters: cluster the Cluster with which this Container is associated.
public void setLoader(
Loader loader)
Set the Loader with which this Container is associated.
Parameters: loader The newly associated loader
public void setManager(
Manager manager)
Set the Manager with which this Container is associated.
Parameters: manager The newly associated Manager
public void setName(String name)
Set a name string (suitable for use by humans) that describes this
Container. Within the set of child containers belonging to a particular
parent, Container names must be unique.
Parameters: name New name of this container
Throws: IllegalStateException if this Container has already been
added to the children of a parent Container (after which the name
may not be changed)
Set the parent Container to which this Container is being added as a
child. This Container may refuse to become attached to the specified
Container by throwing an exception.
Parameters: container Container to which this Container is being added
as a child
Throws: IllegalArgumentException if this Container refuses to become
attached to the specified Container
public void setParentClassLoader(ClassLoader parent)
Set the parent class loader (if any) for web applications.
This call is meaningful only
before a Loader has
been configured, and the specified value (if non-null) should be
passed as an argument to the class loader constructor.
Parameters: parent The new parent class loader
public void setRealm(
Realm realm)
Set the Realm with which this Container is associated.
Parameters: realm The newly associated Realm
public void setResources(DirContext resources)
Set the Resources object with which this Container is associated.
Parameters: resources The newly associated Resources
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