org.apache.shiro.util
Class ThreadContext

java.lang.Object
  extended by org.apache.shiro.util.ThreadContext

public abstract class ThreadContext
extends Object

A ThreadContext provides a means of binding and unbinding objects to the current thread based on key/value pairs.

An internal HashMap is used to maintain the key/value pairs for each thread.

If the desired behavior is to ensure that bound data is not shared across threads in a pooled or reusable threaded environment, the application (or more likely a framework) must bind and remove any necessary values at the beginning and end of stack execution, respectively (i.e. individually explicitly or all via the clear method).

Since:
0.1
See Also:
remove()

Field Summary
static String SECURITY_MANAGER_KEY
           
static String SUBJECT_KEY
           
 
Constructor Summary
protected ThreadContext()
          Default no-argument constructor.
 
Method Summary
static void bind(SecurityManager securityManager)
          Convenience method that simplifies binding the application's SecurityManager instance to the ThreadContext.
static void bind(Subject subject)
          Convenience method that simplifies binding a Subject to the ThreadContext.
static Object get(Object key)
          Returns the object for the specified key that is bound to the current thread.
static Map<Object,Object> getResources()
          Returns the ThreadLocal Map.
static SecurityManager getSecurityManager()
          Convenience method that simplifies retrieval of the application's SecurityManager instance from the current thread.
static Subject getSubject()
          Convenience method that simplifies retrieval of a thread-bound Subject.
static void put(Object key, Object value)
          Binds value for the given key to the current thread.
static void remove()
          Removes the underlying ThreadLocal from the thread.
static Object remove(Object key)
          Unbinds the value for the given key from the current thread.
static void setResources(Map<Object,Object> newResources)
          Allows a caller to explicitly set the entire resource map.
static SecurityManager unbindSecurityManager()
          Convenience method that simplifies removal of the application's SecurityManager instance from the thread.
static Subject unbindSubject()
          Convenience method that simplifies removal of a thread-local Subject from the thread.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

SECURITY_MANAGER_KEY

public static final String SECURITY_MANAGER_KEY

SUBJECT_KEY

public static final String SUBJECT_KEY
Constructor Detail

ThreadContext

protected ThreadContext()
Default no-argument constructor.

Method Detail

getResources

public static Map<Object,Object> getResources()
Returns the ThreadLocal Map. This Map is used internally to bind objects to the current thread by storing each object under a unique key.

Returns:
the map of bound resources

setResources

public static void setResources(Map<Object,Object> newResources)
Allows a caller to explicitly set the entire resource map. This operation overwrites everything that existed previously in the ThreadContext - if you need to retain what was on the thread prior to calling this method, call the getResources() method, which will give you the existing state.

Parameters:
newResources - the resources to replace the existing resources.
Since:
1.0

get

public static Object get(Object key)
Returns the object for the specified key that is bound to the current thread.

Parameters:
key - the key that identifies the value to return
Returns:
the object keyed by key or null if no value exists for the specified key

put

public static void put(Object key,
                       Object value)
Binds value for the given key to the current thread.

A null value has the same effect as if remove was called for the given key, i.e.:

 if ( value == null ) {
     remove( key );
 }

Parameters:
key - The key with which to identify the value.
value - The value to bind to the thread.
Throws:
IllegalArgumentException - if the key argument is null.

remove

public static Object remove(Object key)
Unbinds the value for the given key from the current thread.

Parameters:
key - The key identifying the value bound to the current thread.
Returns:
the object unbound or null if there was nothing bound under the specified key name.

remove

public static void remove()
Removes the underlying ThreadLocal from the thread.

This method is meant to be the final 'clean up' operation that is called at the end of thread execution to prevent thread corruption in pooled thread environments.

Since:
1.0

getSecurityManager

public static SecurityManager getSecurityManager()
Convenience method that simplifies retrieval of the application's SecurityManager instance from the current thread. If there is no SecurityManager bound to the thread (probably because framework code did not bind it to the thread), this method returns null.

It is merely a convenient wrapper for the following:

return (SecurityManager)get( SECURITY_MANAGER_KEY );

This method only returns the bound value if it exists - it does not remove it from the thread. To remove it, one must call unbindSecurityManager() instead.

Returns:
the Subject object bound to the thread, or null if there isn't one bound.
Since:
0.9

bind

public static void bind(SecurityManager securityManager)
Convenience method that simplifies binding the application's SecurityManager instance to the ThreadContext.

The method's existence is to help reduce casting in code and to simplify remembering of ThreadContext key names. The implementation is simple in that, if the SecurityManager is not null, it binds it to the thread, i.e.:

 if (securityManager != null) {
     put( SECURITY_MANAGER_KEY, securityManager);
 }

Parameters:
securityManager - the application's SecurityManager instance to bind to the thread. If the argument is null, nothing will be done.
Since:
0.9

unbindSecurityManager

public static SecurityManager unbindSecurityManager()
Convenience method that simplifies removal of the application's SecurityManager instance from the thread.

The implementation just helps reduce casting and remembering of the ThreadContext key name, i.e it is merely a conveient wrapper for the following:

return (SecurityManager)remove( SECURITY_MANAGER_KEY );

If you wish to just retrieve the object from the thread without removing it (so it can be retrieved later during thread execution), use the getSecurityManager() method instead.

Returns:
the application's SecurityManager instance previously bound to the thread, or null if there was none bound.
Since:
0.9

getSubject

public static Subject getSubject()
Convenience method that simplifies retrieval of a thread-bound Subject. If there is no Subject bound to the thread, this method returns null. It is merely a convenient wrapper for the following:

return (Subject)get( SUBJECT_KEY );

This method only returns the bound value if it exists - it does not remove it from the thread. To remove it, one must call unbindSubject() instead.

Returns:
the Subject object bound to the thread, or null if there isn't one bound.
Since:
0.2

bind

public static void bind(Subject subject)
Convenience method that simplifies binding a Subject to the ThreadContext.

The method's existence is to help reduce casting in your own code and to simplify remembering of ThreadContext key names. The implementation is simple in that, if the Subject is not null, it binds it to the thread, i.e.:

 if (subject != null) {
     put( SUBJECT_KEY, subject );
 }

Parameters:
subject - the Subject object to bind to the thread. If the argument is null, nothing will be done.
Since:
0.2

unbindSubject

public static Subject unbindSubject()
Convenience method that simplifies removal of a thread-local Subject from the thread.

The implementation just helps reduce casting and remembering of the ThreadContext key name, i.e it is merely a conveient wrapper for the following:

return (Subject)remove( SUBJECT_KEY );

If you wish to just retrieve the object from the thread without removing it (so it can be retrieved later during thread execution), you should use the getSubject() method for that purpose.

Returns:
the Subject object previously bound to the thread, or null if there was none bound.
Since:
0.2


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