Context (DSpace Kernel :: API and Implementation 3.4 API)

java.lang.Object
- org.dspace.core.Context

```
public class Context
extends Object
```
Class representing the context of a particular DSpace operation. This stores information such as the current authenticated user and the database connection being used.
Typical use of the context object will involve constructing one, and setting the current user if one is authenticated. Several operations may be performed using the context object. If all goes well, complete is called to commit the changes and free up any resources used by the context. If anything has gone wrong, abort is called to roll back any changes and free up the resources.
The context object is also used as a cache for CM API objects.

Version:

$Revision$

Constructor Summary

Constructors
Constructor and Description

Context()
Construct a new context object.

Constructors
Constructor and Description
`Context()` Construct a new context object.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`abort()` Close the context, without committing any of the changes performed using this context.
`void`	`addEvent(Event event)` Add an event to be dispatched when this context is committed.
`void`	`cache(Object o, int id)` Store an object in the object cache.
`void`	`clearCache()` Remove all the objects from the object cache
`void`	`commit()` Commit any transaction that is currently in progress, but do not close the context.
`void`	`complete()` Close the context object after all of the operations performed in the context have completed successfully.
`protected void`	`finalize()`
`Object`	`fromCache(Class<?> objectClass, int id)` Store an object in the object cache.
`int`	`getCacheSize()` Get the count of cached objects, which you can use to instrument an application to track whether it is "leaking" heap space by letting cached objects build up.
`Locale`	`getCurrentLocale()` Gets the current Locale
`EPerson`	`getCurrentUser()` Get the current (authenticated) user
`Connection`	`getDBConnection()` Get the database connection associated with the context
`LinkedList<Event>`	`getEvents()` Get the current event list.
`String`	`getExtraLogInfo()` Get extra information to be logged with message logged in the scope of this context.
`Group[]`	`getSpecialGroups()` Get an array of all of the special groups that current user is a member of.
`boolean`	`hasEvents()`
`boolean`	`ignoreAuthorization()` Find out if the authorisation system should be ignored for this context.
`boolean`	`inSpecialGroup(int groupID)` test if member of special group
`boolean`	`isValid()` Find out if this context is valid.
`Event`	`pollEvent()` Retrieves the first element in the events list & removes it from the list of events once retrieved
`void`	`removeCached(Object o, int id)` Remove an object from the object cache.
`void`	`restoreAuthSystemState()` Restore the previous Authorisation System State.
`void`	`setCurrentLocale(Locale locale)` set the current Locale
`void`	`setCurrentUser(EPerson user)` Set the current user.
`void`	`setDispatcher(String dispatcher)` Select an event dispatcher, `null` selects the default
`void`	`setExtraLogInfo(String info)` Set extra information that should be added to any message logged in the scope of this context.
`void`	`setIgnoreAuthorization(boolean b)` Deprecated. use turnOffAuthorisationSystem() for make the change and restoreAuthSystemState() when change are not more required
`void`	`setSpecialGroup(int groupID)` set membership in a special group
`void`	`turnOffAuthorisationSystem()` Turn Off the Authorisation System for this context and store this change in a history for future use.

Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - Context
```
public Context()
        throws SQLException
```
    Construct a new context object. A database connection is opened. No user is authenticated.
    
    Throws:
    
    SQLException - if there was an error obtaining a database connection
- Method Detail
  - getDBConnection
```
public Connection getDBConnection()
```
    Get the database connection associated with the context
    
    Returns:
    the database connection
  - setCurrentUser
```
public void setCurrentUser(EPerson user)
```
    Set the current user. Authentication must have been performed by the caller - this call does not attempt any authentication.
    
    Parameters:
    user - the new current user, or null if no user is authenticated
  - getCurrentUser
```
public EPerson getCurrentUser()
```
    Get the current (authenticated) user
    
    Returns:
    the current user, or null if no user is authenticated
  - getCurrentLocale
```
public Locale getCurrentLocale()
```
    Gets the current Locale
    
    Returns:
    Locale the current Locale
  - setCurrentLocale
```
public void setCurrentLocale(Locale locale)
```
    set the current Locale
    
    Parameters:
    locale - the current Locale
  - ignoreAuthorization
```
public boolean ignoreAuthorization()
```
    Find out if the authorisation system should be ignored for this context.
    
    Returns:
    true if authorisation should be ignored for this session.
  - turnOffAuthorisationSystem
```
public void turnOffAuthorisationSystem()
```
    Turn Off the Authorisation System for this context and store this change in a history for future use.
  - restoreAuthSystemState
```
public void restoreAuthSystemState()
```
    Restore the previous Authorisation System State. If the state was not changed by the current caller a warning will be displayed in log. Use: mycontext.turnOffAuthorisationSystem(); some java code that require no authorisation check mycontext.restoreAuthSystemState(); If Context debug is enabled, the correct sequence calling will be checked and a warning will be displayed if not.
  - setIgnoreAuthorization
```
public void setIgnoreAuthorization(boolean b)
```
    Deprecated. use turnOffAuthorisationSystem() for make the change and restoreAuthSystemState() when change are not more required
    
    Specify whether the authorisation system should be ignored for this context. This should be used sparingly.
    
    Parameters:
    b - if true, authorisation should be ignored for this session.
  - setExtraLogInfo
```
public void setExtraLogInfo(String info)
```
    Set extra information that should be added to any message logged in the scope of this context. An example of this might be the session ID of the current Web user's session:
    setExtraLogInfo("session_id="+request.getSession().getId());
    
    Parameters:
    info - the extra information to log
  - getExtraLogInfo
```
public String getExtraLogInfo()
```
    Get extra information to be logged with message logged in the scope of this context.
    
    Returns:
    the extra log info - guaranteed non- null
  - complete
```
public void complete()
              throws SQLException
```
    Close the context object after all of the operations performed in the context have completed successfully. Any transaction with the database is committed.
    
    Throws:
    
    SQLException - if there was an error completing the database transaction or closing the connection
  - commit
```
public void commit()
            throws SQLException
```
    Commit any transaction that is currently in progress, but do not close the context.
    
    Throws:
    
    SQLException - if there was an error completing the database transaction or closing the connection
  - setDispatcher
```
public void setDispatcher(String dispatcher)
```
    Select an event dispatcher, null selects the default
  - addEvent
```
public void addEvent(Event event)
```
    Add an event to be dispatched when this context is committed.
    
    Parameters:
    event -
  - getEvents
```
public LinkedList<Event> getEvents()
```
    Get the current event list. If there is a separate list of events from already-committed operations combine that with current list.
    
    Returns:
    List of all available events.
  - hasEvents
```
public boolean hasEvents()
```
  - pollEvent
```
public Event pollEvent()
```
    Retrieves the first element in the events list & removes it from the list of events once retrieved
    
    Returns:
    The first event of the list or null if the list is empty
  - abort
```
public void abort()
```
    Close the context, without committing any of the changes performed using this context. The database connection is freed. No exception is thrown if there is an error freeing the database connection, since this method may be called as part of an error-handling routine where an SQLException has already been thrown.
  - isValid
```
public boolean isValid()
```
    Find out if this context is valid. Returns false if this context has been aborted or completed.
    
    Returns:
    true if the context is still valid, otherwise false
  - fromCache
```
public Object fromCache(Class<?> objectClass,
               int id)
```
    Store an object in the object cache.
    
    Parameters:
    objectClass - Java Class of object to check for in cache
    id - ID of object in cache
    
    Returns:
    the object from the cache, or null if it's not cached.
  - cache
```
public void cache(Object o,
         int id)
```
    Store an object in the object cache.
    
    Parameters:
    o - the object to store
    id - the object's ID
  - removeCached
```
public void removeCached(Object o,
                int id)
```
    Remove an object from the object cache.
    
    Parameters:
    o - the object to remove
    id - the object's ID
  - clearCache
```
public void clearCache()
```
    Remove all the objects from the object cache
  - getCacheSize
```
public int getCacheSize()
```
    Get the count of cached objects, which you can use to instrument an application to track whether it is "leaking" heap space by letting cached objects build up. We recommend logging a cache count periodically or episodically at the INFO or DEBUG level, but ONLY when you are diagnosing cache leaks.
    
    Returns:
    count of entries in the cache.
  - setSpecialGroup
```
public void setSpecialGroup(int groupID)
```
    set membership in a special group
    
    Parameters:
    groupID - special group's ID
  - inSpecialGroup
```
public boolean inSpecialGroup(int groupID)
```
    test if member of special group
    
    Parameters:
    groupID - ID of special group to test
    
    Returns:
    true if member
  - getSpecialGroups
```
public Group[] getSpecialGroups()
                         throws SQLException
```
    Get an array of all of the special groups that current user is a member of.
    
    Throws:
    
    SQLException
  - finalize
```
protected void finalize()
                 throws Throwable
```
    Overrides:
    
    finalize in class Object
    
    Throws:
    
    Throwable

Class Context

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Context

Method Detail

getDBConnection

setCurrentUser

getCurrentUser

getCurrentLocale

setCurrentLocale

ignoreAuthorization

turnOffAuthorisationSystem

restoreAuthSystemState

setIgnoreAuthorization

setExtraLogInfo

getExtraLogInfo

complete

commit

setDispatcher

addEvent

getEvents

hasEvents

pollEvent

abort

isValid

fromCache

cache

removeCached

clearCache

getCacheSize

setSpecialGroup

inSpecialGroup

getSpecialGroups

finalize