org.apache.jackrabbit.core.data
Class GarbageCollector

java.lang.Object
  org.apache.jackrabbit.core.data.GarbageCollector

public class GarbageCollector
extends Object

Garbage collector for DataStore. This implementation is iterates through all nodes and reads the binary properties. To detect nodes that are moved while the scan runs, event listeners are started. Like the well known garbage collection in Java, the items that are still in use are marked. Currently this achieved by updating the modified date of the entries. Newly added entries are detected because the modified date is changed when they are added.

Example code to run the data store garbage collection:

 GarbageCollector gc = ((SessionImpl)session).createDataStoreGarbageCollector();
 gc.scan();
 gc.stopScan();
 gc.deleteUnused();
 

Constructor Summary

GarbageCollector(SessionImpl session, IterablePersistenceManager[] list, Session[] sessionList)
Create a new garbage collector.

Method Summary

int	deleteUnused()
DataStore	getDataStore()
void	scan() Scan the repository.
void	setScanEventListener(ScanEventListener callback) Set the event listener.
void	setSleepBetweenNodes(int millis) Set the delay between scanning items.
void	setTestDelay(int testDelay) When testing the garbage collection, a delay is used instead of simulating concurrent access.
void	stopScan()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

GarbageCollector

public GarbageCollector(SessionImpl session,
                        IterablePersistenceManager[] list,
                        Session[] sessionList)

Create a new garbage collector. This method is usually not called by the application, it is called by SessionImpl.createDataStoreGarbageCollector().

Parameters:

list - the persistence managers

Method Detail

setSleepBetweenNodes

public void setSleepBetweenNodes(int millis)

Set the delay between scanning items. The main scan loop sleeps this many milliseconds after scanning a node. The default is 0, meaning the scan should run at full speed.

Parameters:

sleepBetweenNodes - the number of milliseconds to sleep

setTestDelay

public void setTestDelay(int testDelay)

When testing the garbage collection, a delay is used instead of simulating concurrent access.

Parameters:

testDelay - the delay in milliseconds

setScanEventListener

public void setScanEventListener(ScanEventListener callback)

Set the event listener. If set, the event listener will be called for each item that is scanned. This mechanism can be used to display the progress.

Parameters:

callback - if set, this is called while scanning

scan

public void scan()
          throws RepositoryException,
                 IllegalStateException,
                 IOException,
                 ItemStateException

Scan the repository. The garbage collector will iterate over all nodes in the repository and update the last modified date. If all persistence managers implement the IterablePersistenceManager interface, this mechanism will be used; if not, the garbage collector will scan the repository using the JCR API starting from the root node.

Throws:

RepositoryException

IllegalStateException

IOException

ItemStateException

stopScan

public void stopScan()
              throws RepositoryException

Throws:

RepositoryException

deleteUnused

public int deleteUnused()
                 throws RepositoryException

Throws:

RepositoryException

getDataStore

public DataStore getDataStore()