# Interface Session

All Known Subinterfaces:
  `ClusterSession`

All Known Implementing Classes:
  `DeltaSession`, `DummyProxySession`, `StandardSession`

public interface Session
A Session is the Catalina-internal facade for an `HttpSession` that is used to maintain state information between requests for a particular user of a web application.

Author:
  Craig R. McClanahan

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `static final String`
  `SESSION_ACTIVATED_EVENT`
  The SessionEvent event type when a session is activated.
  `static final String`
  `SESSION_CREATED_EVENT`
  The SessionEvent event type when a session is created.
  `static final String`
  `SESSION_DESTROYED_EVENT`
  The SessionEvent event type when a session is destroyed.
  `static final String`
  `SESSION_PASSIVATED_EVENT`
  The SessionEvent event type when a session is passivated.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `access()`
  Update the accessed time information for this session.
  `void`
  `addSessionListener(SessionListener listener)`
  Add a session event listener to this component.
  `void`
  `endAccess()`
  End access to the session.
  `void`
  `expire()`
  Perform the internal processing required to invalidate this session, without triggering an exception if the session has already expired.
  `String`
  `getAuthType()`
  `long`
  `getCreationTime()`
  `long`
  `getCreationTimeInternal()`
  `String`
  `getId()`
  `String`
  `getIdInternal()`
  `long`
  `getIdleTime()`
  `long`
  `getIdleTimeInternal()`
  `long`
  `getLastAccessedTime()`
  `long`
  `getLastAccessedTimeInternal()`
  `Manager`
  `getManager()`
  `int`
  `getMaxInactiveInterval()`
  `Object`
  `getNote(String name)`
  `Iterator<String>`
  `getNoteNames()`
  `Principal`
  `getPrincipal()`
  `HttpSession`
  `getSession()`
  `long`
  `getThisAccessedTime()`
  `long`
  `getThisAccessedTimeInternal()`
  `boolean`
  `isAttributeDistributable(String name, Object value)`
  Does the session implementation support the distributing of the given attribute?
  `boolean`
  `isValid()`
  `void`
  `recycle()`
  Release all object references, and initialize instance variables, in preparation for reuse of this object.
  `void`
  `removeNote(String name)`
  Remove any object bound to the specified name in the internal notes for this session.
  `void`
  `removeSessionListener(SessionListener listener)`
  Remove a session event listener from this component.
  `void`
  `setAuthType(String authType)`
  Set the authentication type used to authenticate our cached Principal, if any.
  `void`
  `setCreationTime(long time)`
  Set the creation time for this session.
  `void`
  `setId(String id)`
  Set the session identifier for this session and notifies any associated listeners that a new session has been created.
  `void`
  `setId(String id, boolean notify)`
  Set the session identifier for this session and optionally notifies any associated listeners that a new session has been created.
  `void`
  `setManager(Manager manager)`
  Set the Manager within which this Session is valid.
  `void`
  `setMaxInactiveInterval(int interval)`
  Set the maximum time interval, in seconds, between client requests before the servlet container will invalidate the session.
  `void`
  `setNew(boolean isNew)`
  Set the `isNew` flag for this session.
  `void`
  `setNote(String name, Object value)`
  Bind an object to a specified name in the internal notes associated with this session, replacing any existing binding for this name.
  `void`
  `setPrincipal(Principal principal)`
  Set the authenticated Principal that is associated with this Session.
  `void`
  `setValid(boolean isValid)`
  Set the `isValid` flag for this session.
  `void`
  `tellChangedSessionId(String newId, String oldId, boolean notifySessionListeners, boolean notifyContainerListeners)`
  Inform the listeners about the change session ID.

- ## Field Details

  - ### SESSION_CREATED_EVENT

    static final String SESSION_CREATED_EVENT
    The SessionEvent event type when a session is created.
    See Also:
      - Constant Field Values

  - ### SESSION_DESTROYED_EVENT

    static final String SESSION_DESTROYED_EVENT
    The SessionEvent event type when a session is destroyed.
    See Also:
      - Constant Field Values

  - ### SESSION_ACTIVATED_EVENT

    static final String SESSION_ACTIVATED_EVENT
    The SessionEvent event type when a session is activated.
    See Also:
      - Constant Field Values

  - ### SESSION_PASSIVATED_EVENT

    static final String SESSION_PASSIVATED_EVENT
    The SessionEvent event type when a session is passivated.
    See Also:
      - Constant Field Values

- ## Method Details

  - ### getAuthType

    String getAuthType()
    Returns:
      the authentication type used to authenticate our cached Principal, if any.

  - ### setAuthType

    void setAuthType(String authType)
    Set the authentication type used to authenticate our cached Principal, if any.
    Parameters:
      `authType` - The new cached authentication type

  - ### getCreationTime

    long getCreationTime()
    Returns:
      the creation time for this session.

  - ### getCreationTimeInternal

    long getCreationTimeInternal()
    Returns:
      the creation time for this session, bypassing the session validity checks.

  - ### setCreationTime

    void setCreationTime(long time)
    Set the creation time for this session. This method is called by the Manager when an existing Session instance is reused.
    Parameters:
      `time` - The new creation time

  - ### getId

    String getId()
    Returns:
      the session identifier for this session.

  - ### getIdInternal

    String getIdInternal()
    Returns:
      the session identifier for this session.

  - ### setId

    void setId(String id)
    Set the session identifier for this session and notifies any associated listeners that a new session has been created.
    Parameters:
      `id` - The new session identifier

  - ### setId

    void setId(String id, boolean notify)
    Set the session identifier for this session and optionally notifies any associated listeners that a new session has been created.
    Parameters:
      `id` - The new session identifier
      `notify` - Should any associated listeners be notified that a new session has been created?

  - ### getThisAccessedTime

    long getThisAccessedTime()
    Returns:
      the last time the client sent a request associated with this session, as the number of milliseconds since midnight, January 1, 1970 GMT. Actions that your application takes, such as getting or setting a value associated with the session, do not affect the access time. This one gets updated whenever a request starts.

  - ### getThisAccessedTimeInternal

    long getThisAccessedTimeInternal()
    Returns:
      the last client access time without invalidation check
    See Also:
      - `getThisAccessedTime()`

  - ### getLastAccessedTime

    long getLastAccessedTime()
    Returns:
      the last time the client sent a request associated with this session, as the number of milliseconds since midnight, January 1, 1970 GMT. Actions that your application takes, such as getting or setting a value associated with the session, do not affect the access time. This one gets updated whenever a request finishes.

  - ### getLastAccessedTimeInternal

    long getLastAccessedTimeInternal()
    Returns:
      the last client access time without invalidation check
    See Also:
      - `getLastAccessedTime()`

  - ### getIdleTime

    long getIdleTime()
    Returns:
      the idle time (in milliseconds) from last client access time.

  - ### getIdleTimeInternal

    long getIdleTimeInternal()
    Returns:
      the idle time from last client access time without invalidation check
    See Also:
      - `getIdleTime()`

  - ### getManager

    Manager getManager()
    Returns:
      the Manager within which this Session is valid.

  - ### setManager

    void setManager(Manager manager)
    Set the Manager within which this Session is valid.
    Parameters:
      `manager` - The new Manager

  - ### getMaxInactiveInterval

    int getMaxInactiveInterval()
    Returns:
      the maximum time interval, in seconds, between client requests before the servlet container will invalidate the session. A negative time indicates that the session should never time out.

  - ### setMaxInactiveInterval

    void setMaxInactiveInterval(int interval)
    Set the maximum time interval, in seconds, between client requests before the servlet container will invalidate the session. A negative time indicates that the session should never time out.
    Parameters:
      `interval` - The new maximum interval

  - ### setNew

    void setNew(boolean isNew)
    Set the `isNew` flag for this session.
    Parameters:
      `isNew` - The new value for the `isNew` flag

  - ### getPrincipal

    Principal getPrincipal()
    Returns:
      the authenticated Principal that is associated with this Session. This provides an `Authenticator` with a means to cache a previously authenticated Principal, and avoid potentially expensive `Realm.authenticate()` calls on every request. If there is no current associated Principal, return `null`.

  - ### setPrincipal

    void setPrincipal(Principal principal)
    Set the authenticated Principal that is associated with this Session. This provides an `Authenticator` with a means to cache a previously authenticated Principal, and avoid potentially expensive `Realm.authenticate()` calls on every request.
    Parameters:
      `principal` - The new Principal, or `null` if none

  - ### getSession

    HttpSession getSession()
    Returns:
      the `HttpSession` for which this object is the facade.

  - ### setValid

    void setValid(boolean isValid)
    Set the `isValid` flag for this session.
    Parameters:
      `isValid` - The new value for the `isValid` flag

  - ### isValid

    boolean isValid()
    Returns:
      `true` if the session is still valid

  - ### access

    void access()
    Update the accessed time information for this session. This method should be called by the context when a request comes in for a particular session, even if the application does not reference it.

  - ### addSessionListener

    void addSessionListener(SessionListener listener)
    Add a session event listener to this component.
    Parameters:
      `listener` - the SessionListener instance that should be notified for session events

  - ### endAccess

    void endAccess()
    End access to the session.

  - ### expire

    void expire()
    Perform the internal processing required to invalidate this session, without triggering an exception if the session has already expired.

  - ### getNote

    Object getNote(String name)
    Parameters:
      `name` - Name of the note to be returned
    Returns:
      the object bound with the specified name to the internal notes for this session, or `null` if no such binding exists.

  - ### getNoteNames

    Iterator<String> getNoteNames()
    Returns:
      an Iterator containing the String names of all notes bindings that exist for this session.

  - ### recycle

    void recycle()
    Release all object references, and initialize instance variables, in preparation for reuse of this object.

  - ### removeNote

    void removeNote(String name)
    Remove any object bound to the specified name in the internal notes for this session.
    Parameters:
      `name` - Name of the note to be removed

  - ### removeSessionListener

    void removeSessionListener(SessionListener listener)
    Remove a session event listener from this component.
    Parameters:
      `listener` - remove the session listener, which will no longer be notified

  - ### setNote

    void setNote(String name, Object value)
    Bind an object to a specified name in the internal notes associated with this session, replacing any existing binding for this name.
    Parameters:
      `name` - Name to which the object should be bound
      `value` - Object to be bound to the specified name

  - ### tellChangedSessionId

    void tellChangedSessionId(String newId, String oldId, boolean notifySessionListeners, boolean notifyContainerListeners)
    Inform the listeners about the change session ID.
    Parameters:
      `newId` - new session ID
      `oldId` - old session ID
      `notifySessionListeners` - Should any associated sessionListeners be notified that session ID has been changed?
      `notifyContainerListeners` - Should any associated ContainerListeners be notified that session ID has been changed?

  - ### isAttributeDistributable

    boolean isAttributeDistributable(String name, Object value)
    Does the session implementation support the distributing of the given attribute? If the Manager is marked as distributable, then this method must be used to check attributes before adding them to a session and an `IllegalArgumentException` thrown if the proposed attribute is not distributable.

    Note that the `Manager` implementation may further restrict which attributes are distributed but a `Manager` level restriction should not trigger an `IllegalArgumentException` in `HttpSession.setAttribute(String, Object)`

    Parameters:
      `name` - The attribute name
      `value` - The attribute value
    Returns:
      `true` if distribution is supported, otherwise `false`