org.apache.jackrabbit.core.data
Class FileDataStore

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

All Implemented Interfaces:

DataStore

public class FileDataStore
extends Object
implements DataStore

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

protected Map<DataIdentifier,WeakReference<DataIdentifier>>

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

Constructor Summary

FileDataStore()
Creates a uninitialized data store.

Method Summary

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.
Iterator<DataIdentifier>	getAllIdentifiers() Get all identifiers.
int	getMinRecordLength() Get the minimum size of an object that should be stored in this data store.
String	getPath() Get the name of the directory where this data store keeps the files.
DataRecord	getRecord(DataIdentifier identifier) Returns the record with the given identifier.
DataRecord	getRecordIfStored(DataIdentifier identifier) Check if a record for the given identifier exists, and return it if yes.
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 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()

Creates a uninitialized data store.

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)

Check if a record for the given identifier exists, and return it if yes. If no record exists, this method returns null.

Specified by:

getRecordIfStored in interface DataStore

Parameters:

identifier - data identifier

Returns:

the record if found, and null if not

getRecord

public DataRecord getRecord(DataIdentifier identifier)
                     throws DataStoreException

Returns the record with the given identifier. Note that this method performs no sanity checks on the given identifier. It is up to the caller to ensure that only identifiers of previously created data records are used.

Specified by:

getRecord in interface DataStore

Parameters:

identifier - data identifier

Returns:

identified data record

Throws:

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

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 SHA-1 message digest of the stream is calculated. If a record with the same SHA-1 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)

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

deleteAllOlderThan

public int deleteAllOlderThan(long min)

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()

Get all identifiers.

Specified by:

getAllIdentifiers in interface DataStore

Returns:

an iterator over all DataIdentifier objects

clearInUse

public void clearInUse()

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()

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()

Close the data store

Specified by:

close in interface DataStore