org.apache.jackrabbit.core.data

Class FileDataStore

java.lang.Object

org.apache.jackrabbit.core.data.AbstractDataStore

org.apache.jackrabbit.core.data.FileDataStore

All Implemented Interfaces:

DataStore, MultiDataStoreAware

public class FileDataStore
extends AbstractDataStore
implements MultiDataStoreAware

Simple file-based data store. Data records are stored as normal files named using a message digest of the contained binary stream. Configuration:

 <DataStore class="org.apache.jackrabbit.core.data.FileDataStore">
     <param name="path" value="/data/datastore"/>
     <param name="minRecordLength" value="1024"/>
 </DataStore>
 

If the directory is not set, the directory <repository home>/repository/datastore is used.

A three level directory structure is used to avoid placing too many files in a single directory. The chosen structure is designed to scale up to billions of distinct records.

This implementation relies on the underlying file system to support atomic O(1) move operations with File.renameTo(File).

Field Summary

Fields

Modifier and Type	Field and Description
protected Map<DataIdentifier,WeakReference<DataIdentifier>>	inUse All data identifiers that are currently in use are in this set until they are garbage collected.

Fields inherited from class org.apache.jackrabbit.core.data.AbstractDataStore

DIGEST

Constructor Summary

Constructors

Constructor and Description
FileDataStore()

Method Summary

Modifier and Type	Method and Description
DataRecord	addRecord(InputStream input) Creates a new data record.
void	clearInUse() Clear the in-use list.
void	close() Close the data store
int	deleteAllOlderThan(long min) Delete objects that have a modified date older than the specified date.
void	deleteRecord(DataIdentifier identifier) Deletes a single DataRecord based on the given identifier.
Iterator<DataIdentifier>	getAllIdentifiers() Get all identifiers.
int	getMinRecordLength() Get the minimum size of an object that should be stored in this data store.
protected byte[]	getOrCreateReferenceKey() Returns the reference key of this data store.
String	getPath() Get the name of the directory where this data store keeps the files.
DataRecord	getRecordIfStored(DataIdentifier identifier) Get a data record for the given identifier.
void	init(String homeDir) Initialized the data store.
void	setMinRecordLength(int minRecordLength) Set the minimum object length.
void	setPath(String directoryName) Set the name of the directory where this data store keeps the files.
void	updateModifiedDateOnAccess(long before) From now on, update the modified date of an object even when accessing it.

Methods inherited from class org.apache.jackrabbit.core.data.AbstractDataStore

encodeHexString, getRecord, getRecordFromReference, getReferenceFromIdentifier

Methods inherited from class java.lang.Object

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

Field Detail

inUse

protected Map<DataIdentifier,WeakReference<DataIdentifier>> inUse

All data identifiers that are currently in use are in this set until they are garbage collected.

Constructor Detail

FileDataStore

public FileDataStore()

Method Detail

init

public void init(String homeDir)

Initialized the data store. If the path is not set, <repository home>/repository/datastore is used. This directory is automatically created if it does not yet exist.

Specified by:

init in interface DataStore

Parameters:

homeDir -

getRecordIfStored

public DataRecord getRecordIfStored(DataIdentifier identifier)
                             throws DataStoreException

Get a data record for the given identifier.

Specified by:

getRecordIfStored in interface DataStore

Parameters:

identifier - the identifier

Returns:

the data record or null

Throws:

DataStoreException - if the data store could not be accessed

addRecord

public DataRecord addRecord(InputStream input)
                     throws DataStoreException

Creates a new data record. The stream is first consumed and the contents are saved in a temporary file and the AbstractDataStore.DIGEST message digest of the stream is calculated. If a record with the same AbstractDataStore.DIGEST digest (and length) is found then it is returned. Otherwise the temporary file is moved in place to become the new data record that gets returned.

Specified by:

addRecord in interface DataStore

Parameters:

input - binary stream

Returns:

data record that contains the given stream

Throws:

DataStoreException - if the record could not be created

updateModifiedDateOnAccess

public void updateModifiedDateOnAccess(long before)

Description copied from interface: DataStore

From now on, update the modified date of an object even when accessing it. Usually, the modified date is only updated when creating a new object, or when a new link is added to an existing object. When this setting is enabled, even getLength() will update the modified date.

Specified by:

updateModifiedDateOnAccess in interface DataStore

Parameters:

before - - update the modified date to the current time if it is older than this value

deleteRecord

public void deleteRecord(DataIdentifier identifier)
                  throws DataStoreException

Description copied from interface: MultiDataStoreAware

Deletes a single DataRecord based on the given identifier. Delete will only be used by the MultiDataStore.MoveDataTask.

Specified by:

deleteRecord in interface MultiDataStoreAware

Parameters:

identifier - data identifier

Throws:

DataStoreException - if the data store could not be accessed, or if the given identifier is invalid

deleteAllOlderThan

public int deleteAllOlderThan(long min)

Description copied from interface: DataStore

Delete objects that have a modified date older than the specified date.

Specified by:

deleteAllOlderThan in interface DataStore

Parameters:

min - the minimum time

Returns:

the number of data records deleted

getAllIdentifiers

public Iterator<DataIdentifier> getAllIdentifiers()

Description copied from interface: DataStore

Get all identifiers.

Specified by:

getAllIdentifiers in interface DataStore

Returns:

an iterator over all DataIdentifier objects

clearInUse

public void clearInUse()

Description copied from interface: DataStore

Clear the in-use list. This is only used for testing to make the the garbage collection think that objects are no longer in use.

Specified by:

clearInUse in interface DataStore

getPath

public String getPath()

Get the name of the directory where this data store keeps the files.

Returns:

the full path name

setPath

public void setPath(String directoryName)

Set the name of the directory where this data store keeps the files.

Parameters:

directoryName - the path name

getMinRecordLength

public int getMinRecordLength()

Description copied from interface: DataStore

Get the minimum size of an object that should be stored in this data store. Depending on the overhead and configuration, each store may return a different value.

Specified by:

getMinRecordLength in interface DataStore

Returns:

the minimum size in bytes

setMinRecordLength

public void setMinRecordLength(int minRecordLength)

Set the minimum object length.

Parameters:

minRecordLength - the length

close

public void close()

Description copied from interface: DataStore

Close the data store

Specified by:

close in interface DataStore

getOrCreateReferenceKey

protected byte[] getOrCreateReferenceKey()
                                  throws DataStoreException

Description copied from class: AbstractDataStore

Returns the reference key of this data store. If one does not already exist, it is automatically created in an implementation-specific way. The default implementation simply creates a temporary random key that's valid only until the data store gets restarted. Subclasses can override and/or decorate this method to support a more persistent reference key.

This method is called only once during the lifetime of a data store instance and the return value is cached in memory, so it's no problem if the implementation is slow.

Overrides:

getOrCreateReferenceKey in class AbstractDataStore

Returns:

reference key

Throws:

DataStoreException - if the key is not available