/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.catalina;
import java.beans.PropertyChangeListener;
import java.io.File;
import javax.management.ObjectName;
import org.apache.catalina.connector.Request;
import org.apache.catalina.connector.Response;
import org.apache.juli.logging.Log;
/**
* A <b>Container</b> 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 <b>Pipeline</b> interface as well.
* <p>
* Containers will exist at several conceptual levels within Catalina. The following examples represent common cases:
* <ul>
* <li><b>Engine</b> - 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.
* <li><b>Host</b> - Representation of a virtual host containing a number of Contexts.
* <li><b>Context</b> - Representation of a single ServletContext, which will typically contain one or more Wrappers for
* the supported servlets.
* <li><b>Wrapper</b> - Representation of an individual servlet definition.
* </ul>
* 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.
* <p>
* 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:
* <ul>
* <li><b>Loader</b> - Class loader to use for integrating new Java classes for this Container into the JVM in which
* Catalina is running.
* <li><b>Logger</b> - Implementation of the <code>log()</code> method signatures of the <code>ServletContext</code>
* interface.
* <li><b>Manager</b> - Manager for the pool of Sessions associated with this Container.
* <li><b>Realm</b> - Read-only interface to a security domain, for authenticating user identities and their
* corresponding roles.
* <li><b>Resources</b> - JNDI directory context enabling access to static resources, enabling custom linkages to
* existing server components when Catalina is embedded in a larger server.
* </ul>
*/
public interface Container extends Lifecycle {
// ----------------------------------------------------- Manifest Constants
/**
* The ContainerEvent event type sent when a child container is added by <code>addChild()</code>.
*/
String ADD_CHILD_EVENT = "addChild";
/**
* The ContainerEvent event type sent when a valve is added by <code>addValve()</code>, if this Container supports
* pipelines.
*/
String ADD_VALVE_EVENT = "addValve";
/**
* The ContainerEvent event type sent when a child container is removed by <code>removeChild()</code>.
*/
String REMOVE_CHILD_EVENT = "removeChild";
/**
* The ContainerEvent event type sent when a valve is removed by <code>removeValve()</code>, if this Container
* supports pipelines.
*/
String REMOVE_VALVE_EVENT = "removeValve";
// ------------------------------------------------------------- Properties
/**
* Obtain the log to which events for this container should be logged.
*
* @return The Logger with which this Container is associated. If there is no associated Logger, return the Logger
* associated with the parent Container (if any); otherwise return <code>null</code>.
*/
Log getLogger();
/**
* Return the logger name that the container will use.
*
* @return the abbreviated name of this container for logging messages
*/
String getLogName();
/**
* Obtain the JMX name for this container.
*
* @return the JMX name associated with this container.
*/
ObjectName getObjectName();
/**
* Obtain the JMX domain under which this container will be / has been registered.
*
* @return The JMX domain name
*/
String getDomain();
/**
* Calculate the key properties string to be added to an object's {@link ObjectName} to indicate that it is
* associated with this container.
*
* @return A string suitable for appending to the ObjectName
*/
String getMBeanKeyProperties();
/**
* Return the Pipeline object that manages the Valves associated with this Container.
*
* @return The Pipeline
*/
Pipeline getPipeline();
/**
* Get the Cluster for this container.
*
* @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 <code>null</code>.
*/
Cluster getCluster();
/**
* Set the Cluster with which this Container is associated.
*
* @param cluster the Cluster with which this Container is associated.
*/
void setCluster(Cluster cluster);
/**
* 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 positive (which would mean they are using their own
* thread). Setting this to a positive value will cause a thread to be spawned. After waiting the specified amount
* of time, the thread will invoke the {@link #backgroundProcess()} method on this container and all children with
* non-positive delay values.
*
* @return The delay between the invocation of the backgroundProcess method on this container and its children. A
* non-positive value indicates that background processing will be managed by the parent.
*/
int getBackgroundProcessorDelay();
/**
* Set the delay between the invocation of the execute method on this container and its children.
*
* @param delay The delay in seconds between the invocation of backgroundProcess methods
*/
void setBackgroundProcessorDelay(int delay);
/**
* 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.
*
* @return The human readable name of this container.
*/
String getName();
/**
* 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.
*
* @param name New name of this container
*
* @exception IllegalStateException if this Container has already been added to the children of a parent Container
* (after which the name may not be changed)
*/
void setName(String name);
/**
* Get the parent container.
*
* @return Return the Container for which this Container is a child, if there is one. If there is no defined parent,
* return <code>null</code>.
*/
Container getParent();
/**
* 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.
*
* @param container Container to which this Container is being added as a child
*
* @exception IllegalArgumentException if this Container refuses to become attached to the specified Container
*/
void setParent(Container container);
/**
* Get the parent class loader.
*
* @return the parent class loader for this component. If not set, return
* {@link #getParent()}.{@link #getParentClassLoader()}. If no parent has been set, return the system
* class loader.
*/
ClassLoader getParentClassLoader();
/**
* Set the parent class loader for this component. For {@link Context}s this call is meaningful only
* <strong>before</strong> a Loader has been configured, and the specified value (if non-null) should be passed as
* an argument to the class loader constructor.
*
* @param parent The new parent class loader
*/
void setParentClassLoader(ClassLoader parent);
/**
* Obtain the Realm with which this Container is associated.
*
* @return The associated Realm; if there is no associated Realm, the Realm associated with the parent Container (if
* any); otherwise return <code>null</code>.
*/
Realm getRealm();
/**
* Set the Realm with which this Container is associated.
*
* @param realm The newly associated Realm
*/
void setRealm(Realm realm);
/**
* Find the configuration path where a configuration resource is located.
*
* @param container The container
* @param resourceName The resource file name
*
* @return the configuration path
*/
static String getConfigPath(Container container, String resourceName) {
StringBuilder result = new StringBuilder();
Container host = null;
Container engine = null;
while (container != null) {
if (container instanceof Host) {
host = container;
} else if (container instanceof Engine) {
engine = container;
}
container = container.getParent();
}
if (host != null && ((Host) host).getXmlBase() != null) {
result.append(((Host) host).getXmlBase()).append('/');
} else {
result.append("conf/");
if (engine != null) {
result.append(engine.getName()).append('/');
}
if (host != null) {
result.append(host.getName()).append('/');
}
}
result.append(resourceName);
return result.toString();
}
/**
* Return the Service to which this container belongs.
*
* @param container The container to start from
*
* @return the Service, or null if not found
*/
static Service getService(Container container) {
while (container != null && !(container instanceof Engine)) {
container = container.getParent();
}
if (container == null) {
return null;
}
return ((Engine) container).getService();
}
// --------------------------------------------------------- Public Methods
/**
* 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.
*/
void backgroundProcess();
/**
* 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 <code>setParent()</code> method must be called, with this Container as an
* argument. This method may throw an <code>IllegalArgumentException</code> if this Container chooses not to be
* attached to the specified Container, in which case it is not added
*
* @param child New child Container to be added
*
* @exception IllegalArgumentException if this exception is thrown by the <code>setParent()</code> method of the
* child Container
* @exception IllegalArgumentException if the new child does not have a name unique from that of existing children
* of this Container
* @exception IllegalStateException if this Container does not support child Containers
*/
void addChild(Container child);
/**
* Add a container event listener to this component.
*
* @param listener The listener to add
*/
void addContainerListener(ContainerListener listener);
/**
* Add a property change listener to this component.
*
* @param listener The listener to add
*/
void addPropertyChangeListener(PropertyChangeListener listener);
/**
* Obtain a child Container by name.
*
* @param name Name of the child Container to be retrieved
*
* @return The child Container with the given name or <code>null</code> if no such child exists.
*/
Container findChild(String name);
/**
* Obtain the child Containers associated with this Container.
*
* @return An array containing all children of this container. If this Container has no children, a zero-length
* array is returned.
*/
Container[] findChildren();
/**
* Obtain the container listeners associated with this Container.
*
* @return An array containing the container listeners associated with this Container. If this Container has no
* registered container listeners, a zero-length array is returned.
*/
ContainerListener[] findContainerListeners();
/**
* Remove an existing child Container from association with this parent Container.
*
* @param child Existing child Container to be removed
*/
void removeChild(Container child);
/**
* Remove a container event listener from this component.
*
* @param listener The listener to remove
*/
void removeContainerListener(ContainerListener listener);
/**
* Remove a property change listener from this component.
*
* @param listener The listener to remove
*/
void removePropertyChangeListener(PropertyChangeListener listener);
/**
* Notify all container event listeners that a particular event has occurred for this Container. The default
* implementation performs this notification synchronously using the calling thread.
*
* @param type Event type
* @param data Event data
*/
void fireContainerEvent(String type, Object data);
/**
* Log a request/response that was destined for this container but has been handled earlier in the processing chain
* so that the request/response still appears in the correct access logs.
*
* @param request Request (associated with the response) to log
* @param response Response (associated with the request) to log
* @param time Time taken to process the request/response in nanoseconds (use 0 if not known)
* @param useDefault Flag that indicates that the request/response should be logged in the engine's default access
* log
*/
void logAccess(Request request, Response response, long time, boolean useDefault);
/**
* Obtain the AccessLog to use to log a request/response that is destined for this container. This is typically used
* when the request/response was handled (and rejected) earlier in the processing chain so that the request/response
* still appears in the correct access logs.
*
* @return The AccessLog to use for a request/response destined for this container
*/
AccessLog getAccessLog();
/**
* Obtain the number of threads available for starting and stopping any children associated with this container.
* This allows start/stop calls to children to be processed in parallel.
*
* @return The currently configured number of threads used to start/stop children associated with this container
*/
int getStartStopThreads();
/**
* Sets the number of threads available for starting and stopping any children associated with this container. This
* allows start/stop calls to children to be processed in parallel.
*
* @param startStopThreads The new number of threads to be used
*/
void setStartStopThreads(int startStopThreads);
/**
* Obtain the location of CATALINA_BASE.
*
* @return The location of CATALINA_BASE.
*/
File getCatalinaBase();
/**
* Obtain the location of CATALINA_HOME.
*
* @return The location of CATALINA_HOME.
*/
File getCatalinaHome();
}