Manager.java
/*
* 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.IOException;
/**
* A <b>Manager</b> manages the pool of Sessions that are associated with a
* particular Context. Different Manager implementations may support
* value-added features such as the persistent storage of session data,
* as well as migrating sessions for distributable web applications.
* <p>
* In order for a <code>Manager</code> implementation to successfully operate
* with a <code>Context</code> implementation that implements reloading, it
* must obey the following constraints:
* <ul>
* <li>Must implement <code>Lifecycle</code> so that the Context can indicate
* that a restart is required.
* <li>Must allow a call to <code>stop()</code> to be followed by a call to
* <code>start()</code> on the same <code>Manager</code> instance.
* </ul>
*
* @author Craig R. McClanahan
*/
public interface Manager {
// ------------------------------------------------------------- Properties
/**
* Get the Context with which this Manager is associated.
*
* @return The associated Context
*/
Context getContext();
/**
* Set the Context with which this Manager is associated. The Context must
* be set to a non-null value before the Manager is first used. Multiple
* calls to this method before first use are permitted. Once the Manager has
* been used, this method may not be used to change the Context (including
* setting a {@code null} value) that the Manager is associated with.
*
* @param context The newly associated Context
*/
void setContext(Context context);
/**
* @return the session id generator
*/
SessionIdGenerator getSessionIdGenerator();
/**
* Sets the session id generator
*
* @param sessionIdGenerator The session id generator
*/
void setSessionIdGenerator(SessionIdGenerator sessionIdGenerator);
/**
* Returns the total number of sessions created by this manager, which is
* approximated as the number of active sessions plus the number of
* expired sessions.
*
* @return Total number of sessions created by this manager.
*/
long getSessionCounter();
/**
* Sets the total number of sessions created by this manager.
*
* @param sessionCounter Total number of sessions created by this manager.
* @deprecated This will be removed in Tomcat 11
*/
@Deprecated
void setSessionCounter(long sessionCounter);
/**
* Gets the maximum number of sessions that have been active at the same
* time.
*
* @return Maximum number of sessions that have been active at the same
* time
*/
int getMaxActive();
/**
* (Re)sets the maximum number of sessions that have been active at the
* same time.
*
* @param maxActive Maximum number of sessions that have been active at
* the same time.
*/
void setMaxActive(int maxActive);
/**
* Gets the number of currently active sessions.
*
* @return Number of currently active sessions
*/
int getActiveSessions();
/**
* Gets the number of sessions that have expired.
*
* @return Number of sessions that have expired
*/
long getExpiredSessions();
/**
* Sets the number of sessions that have expired.
*
* @param expiredSessions Number of sessions that have expired
*/
void setExpiredSessions(long expiredSessions);
/**
* Gets the number of sessions that were not created because the maximum
* number of active sessions was reached.
*
* @return Number of rejected sessions
*/
int getRejectedSessions();
/**
* Gets the longest time (in seconds) that an expired session had been
* alive.
*
* @return Longest time (in seconds) that an expired session had been
* alive.
*/
int getSessionMaxAliveTime();
/**
* Sets the longest time (in seconds) that an expired session had been
* alive.
*
* @param sessionMaxAliveTime Longest time (in seconds) that an expired
* session had been alive.
*/
void setSessionMaxAliveTime(int sessionMaxAliveTime);
/**
* Gets the average time (in seconds) that expired sessions had been
* alive. This may be based on sample data.
*
* @return Average time (in seconds) that expired sessions had been
* alive.
*/
int getSessionAverageAliveTime();
/**
* Gets the current rate of session creation (in session per minute). This
* may be based on sample data.
*
* @return The current rate (in sessions per minute) of session creation
*/
int getSessionCreateRate();
/**
* Gets the current rate of session expiration (in session per minute). This
* may be based on sample data
*
* @return The current rate (in sessions per minute) of session expiration
*/
int getSessionExpireRate();
// --------------------------------------------------------- Public Methods
/**
* Add this Session to the set of active Sessions for this Manager.
*
* @param session Session to be added
*/
void add(Session session);
/**
* Add a property change listener to this component.
*
* @param listener The listener to add
*/
void addPropertyChangeListener(PropertyChangeListener listener);
/**
* Change the session ID of the current session to a new randomly generated
* session ID.
*
* @param session The session to change the session ID for
*
* @return The new session ID
*/
default String rotateSessionId(Session session) {
String newSessionId = null;
// Assume the new Id is a duplicate until we prove it isn't. The
// chances of a duplicate are extremely low but the current ManagerBase
// code protects against duplicates so this default method does too.
boolean duplicate = true;
do {
newSessionId = getSessionIdGenerator().generateSessionId();
try {
if (findSession(newSessionId) == null) {
duplicate = false;
}
} catch (IOException ioe) {
// Swallow. An IOE means the ID was known so continue looping
}
} while (duplicate);
changeSessionId(session, newSessionId);
return newSessionId;
}
/**
* Change the session ID of the current session to a specified session ID.
*
* @param session The session to change the session ID for
* @param newId new session ID
*/
void changeSessionId(Session session, String newId);
/**
* Get a session from the recycled ones or create a new empty one.
* The PersistentManager manager does not need to create session data
* because it reads it from the Store.
*
* @return An empty Session object
*/
Session createEmptySession();
/**
* Construct and return a new session object, based on the default
* settings specified by this Manager's properties. The session
* id specified will be used as the session id.
* If a new session cannot be created for any reason, return
* <code>null</code>.
*
* @param sessionId The session id which should be used to create the
* new session; if <code>null</code>, the session
* id will be assigned by this method, and available via the getId()
* method of the returned session.
* @exception IllegalStateException if a new session cannot be
* instantiated for any reason
*
* @return An empty Session object with the given ID or a newly created
* session ID if none was specified
*/
Session createSession(String sessionId);
/**
* Return the active Session, associated with this Manager, with the
* specified session id (if any); otherwise return <code>null</code>.
*
* @param id The session id for the session to be returned
*
* @exception IllegalStateException if a new session cannot be
* instantiated for any reason
* @exception IOException if an input/output error occurs while
* processing this request
*
* @return the request session or {@code null} if a session with the
* requested ID could not be found
*/
Session findSession(String id) throws IOException;
/**
* Return the set of active Sessions associated with this Manager.
* If this Manager has no active Sessions, a zero-length array is returned.
*
* @return All the currently active sessions managed by this manager
*/
Session[] findSessions();
/**
* Load any currently active sessions that were previously unloaded
* to the appropriate persistence mechanism, if any. If persistence is not
* supported, this method returns without doing anything.
*
* @exception ClassNotFoundException if a serialized class cannot be
* found during the reload
* @exception IOException if an input/output error occurs
*/
void load() throws ClassNotFoundException, IOException;
/**
* Remove this Session from the active Sessions for this Manager.
*
* @param session Session to be removed
*/
void remove(Session session);
/**
* Remove this Session from the active Sessions for this Manager.
*
* @param session Session to be removed
* @param update Should the expiration statistics be updated
*/
void remove(Session session, boolean update);
/**
* Remove a property change listener from this component.
*
* @param listener The listener to remove
*/
void removePropertyChangeListener(PropertyChangeListener listener);
/**
* Save any currently active sessions in the appropriate persistence
* mechanism, if any. If persistence is not supported, this method
* returns without doing anything.
*
* @exception IOException if an input/output error occurs
*/
void unload() throws IOException;
/**
* This method will be invoked by the context/container on a periodic
* basis and allows the manager to implement
* a method that executes periodic tasks, such as expiring sessions etc.
*/
void backgroundProcess();
/**
* Would the Manager distribute the given session attribute? Manager
* implementations may provide additional configuration options to control
* which attributes are distributable.
*
* @param name The attribute name
* @param value The attribute value
*
* @return {@code true} if the Manager would distribute the given attribute
* otherwise {@code false}
*/
boolean willAttributeDistribute(String name, Object value);
/**
* When an attribute that is already present in the session is added again
* under the same name and the attribute implements {@link
* jakarta.servlet.http.HttpSessionBindingListener}, should
* {@link jakarta.servlet.http.HttpSessionBindingListener#valueUnbound(jakarta.servlet.http.HttpSessionBindingEvent)}
* be called followed by
* {@link jakarta.servlet.http.HttpSessionBindingListener#valueBound(jakarta.servlet.http.HttpSessionBindingEvent)}?
* <p>
* The default value is {@code false}.
*
* @return {@code true} if the listener will be notified, {@code false} if
* it will not
*/
default boolean getNotifyBindingListenerOnUnchangedValue() {
return false;
}
/**
* Configure if
* {@link jakarta.servlet.http.HttpSessionBindingListener#valueUnbound(jakarta.servlet.http.HttpSessionBindingEvent)}
* be called followed by
* {@link jakarta.servlet.http.HttpSessionBindingListener#valueBound(jakarta.servlet.http.HttpSessionBindingEvent)}
* when an attribute that is already present in the session is added again
* under the same name and the attribute implements {@link
* jakarta.servlet.http.HttpSessionBindingListener}.
*
* @param notifyBindingListenerOnUnchangedValue {@code true} the listener
* will be called, {@code
* false} it will not
*/
void setNotifyBindingListenerOnUnchangedValue(
boolean notifyBindingListenerOnUnchangedValue);
/**
* When an attribute that is already present in the session is added again
* under the same name and a {@link
* jakarta.servlet.http.HttpSessionAttributeListener} is configured for the
* session should
* {@link jakarta.servlet.http.HttpSessionAttributeListener#attributeReplaced(jakarta.servlet.http.HttpSessionBindingEvent)}
* be called?
* <p>
* The default value is {@code true}.
*
* @return {@code true} if the listener will be notified, {@code false} if
* it will not
*/
default boolean getNotifyAttributeListenerOnUnchangedValue() {
return true;
}
/**
* Configure if
* {@link jakarta.servlet.http.HttpSessionAttributeListener#attributeReplaced(jakarta.servlet.http.HttpSessionBindingEvent)}
* when an attribute that is already present in the session is added again
* under the same name and a {@link
* jakarta.servlet.http.HttpSessionAttributeListener} is configured for the
* session.
*
* @param notifyAttributeListenerOnUnchangedValue {@code true} the listener
* will be called, {@code
* false} it will not
*/
void setNotifyAttributeListenerOnUnchangedValue(
boolean notifyAttributeListenerOnUnchangedValue);
/**
* If this is <code>true</code>, Tomcat will track the number of active
* requests for each session. When determining if a session is valid, any
* session with at least one active request will always be considered valid.
* If <code>org.apache.catalina.STRICT_SERVLET_COMPLIANCE</code> is set to
* <code>true</code>, the default of this setting will be <code>true</code>,
* else the default value will be <code>false</code>.
* @return the flag value
*/
default boolean getSessionActivityCheck() {
return Globals.STRICT_SERVLET_COMPLIANCE;
}
/**
* Configure if Tomcat will track the number of active requests for each
* session. When determining if a session is valid, any session with at
* least one active request will always be considered valid.
* @param sessionActivityCheck the new flag value
*/
void setSessionActivityCheck(boolean sessionActivityCheck);
/**
* If this is <code>true</code>, the last accessed time for sessions will
* be calculated from the beginning of the previous request. If
* <code>false</code>, the last accessed time for sessions will be calculated
* from the end of the previous request. This also affects how the idle time
* is calculated.
* If <code>org.apache.catalina.STRICT_SERVLET_COMPLIANCE</code> is set to
* <code>true</code>, the default of this setting will be <code>true</code>,
* else the default value will be <code>false</code>.
* @return the flag value
*/
default boolean getSessionLastAccessAtStart() {
return Globals.STRICT_SERVLET_COMPLIANCE;
}
/**
* Configure if the last accessed time for sessions will
* be calculated from the beginning of the previous request. If
* <code>false</code>, the last accessed time for sessions will be calculated
* from the end of the previous request. This also affects how the idle time
* is calculated.
* @param sessionLastAccessAtStart the new flag value
*/
void setSessionLastAccessAtStart(boolean sessionLastAccessAtStart);
}