org.apache.commons.configuration2.sync

Interface SynchronizerSupport

All Known Subinterfaces:

Configuration, FileBasedConfiguration, HierarchicalConfiguration<T>

All Known Implementing Classes:

AbstractConfiguration, AbstractHierarchicalConfiguration, AbstractYAMLBasedConfiguration, AppletConfiguration, BaseConfiguration, BaseHierarchicalConfiguration, CombinedConfiguration, CompositeConfiguration, DatabaseConfiguration, DataConfiguration, DynamicCombinedConfiguration, EnvironmentConfiguration, INIConfiguration, JNDIConfiguration, JSONConfiguration, MapConfiguration, PatternSubtreeConfigurationWrapper, PropertiesConfiguration, PropertyListConfiguration, ServletConfiguration, ServletContextConfiguration, ServletFilterConfiguration, ServletRequestConfiguration, SubnodeConfiguration, SubsetConfiguration, SystemConfiguration, XMLConfiguration, XMLPropertiesConfiguration, XMLPropertyListConfiguration, YAMLConfiguration

public interface SynchronizerSupport

Definition of an interface for objects that can be associated with a Synchronizer.

This interface defines methods for querying and setting the Synchronizer. In addition, it is possible to lock the object for a certain operation. This is useful if some complex operations are to be performed on the SynchronizerSupport object in an atomic way.

Note that the actual effect of these methods depends on the concrete Synchronizer implementation in use! If only a dummy Synchronizer is involved (which is appropriate if objects are only accessed by a single thread), locking an object does not really prohibit concurrent access.

Since:

2.0

Method Summary

Modifier and Type	Method and Description
Synchronizer	getSynchronizer() Returns the Synchronizer used by this object.
void	lock(LockMode mode) Locks this object for the specified mode.
void	setSynchronizer(Synchronizer sync) Sets the Synchronizer to be used by this object.
void	unlock(LockMode mode) Releases a lock of this object that was obtained using the lock(LockMode) method.

Method Detail

getSynchronizer

Synchronizer getSynchronizer()

Returns the Synchronizer used by this object. An implementation must not return null. If no Synchronizer has been set so far, a meaningful default Synchronizer has to be returned.

Returns:

the Synchronizer used by this object

setSynchronizer

void setSynchronizer(Synchronizer sync)

Sets the Synchronizer to be used by this object. Calling this method and setting an appropriate Synchronizer determines whether this object can be accessed in a thread-safe way or not. The argument may be null; in this case an implementation should switch to a default Synchronizer.

Parameters:

sync - the Synchronizer for this object

lock

void lock(LockMode mode)

Locks this object for the specified mode. This call may block until this object is released from other lock operations. When it returns the caller can access the object in a way compatible to the specified LockMode. When done the unlock() must be called with the same LockMode argument. In practice, a try-finally construct should be used as in the following example:

 SynchronizerSupport syncSupport = ...;
 syncSupport.lock(LockMode.READ);
 try
 {
     // read access to syncSupport
 }
 finally
 {
     syncSupport.unlock(LockMode.READ);
 }
 

Note: Always use this method for obtaining a lock rather than accessing the object's Synchronizer directly. An implementation may perform additional actions which are not executed when only interacting with the Synchronizer.

Parameters:

mode - the LockMode

unlock

void unlock(LockMode mode)

Releases a lock of this object that was obtained using the lock(LockMode) method. This method must always be called pair-wise with lock(). The argument must match to the one passed to the corresponding lock() call; otherwise, the behavior of the Synchronizer is unspecified.

Parameters:

mode - the LockMode