Package org.apache.jackrabbit.core.data

Class AbstractDataStore

java.lang.Object

org.apache.jackrabbit.core.data.AbstractDataStore

All Implemented Interfaces:

DataStore

Direct Known Subclasses:

CachingDataStore, DbDataStore, FileDataStore

public abstract class AbstractDataStore
extends Object
implements DataStore

Field Summary

Fields

Modifier and Type	Field	Description
protected String	DIGEST	The digest algorithm used to uniquely identify records.

Constructor Summary

Constructors

Constructor	Description
AbstractDataStore()

Method Summary

Modifier and Type	Method	Description
protected static String	encodeHexString(byte[] value)	Returns the hex encoding of the given bytes.
protected byte[]	getOrCreateReferenceKey()	Returns the reference key of this data store.
DataRecord	getRecord(DataIdentifier identifier)	Returns the identified data record.
DataRecord	getRecordFromReference(String reference)	Returns the record that matches the given binary reference.
protected String	getReferenceFromIdentifier(DataIdentifier identifier)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.jackrabbit.core.data.DataStore

addRecord, clearInUse, close, deleteAllOlderThan, getAllIdentifiers, getMinRecordLength, getRecordIfStored, init, updateModifiedDateOnAccess

Field Detail

DIGEST

protected String DIGEST

The digest algorithm used to uniquely identify records.

Constructor Detail

AbstractDataStore

public AbstractDataStore()

Method Detail

getRecord

public DataRecord getRecord(DataIdentifier identifier)
                     throws DataStoreException

Description copied from interface: DataStore

Returns the identified data record. The given identifier should be the identifier of a previously saved data record. Since records are never removed, there should never be cases where the identified record is not found. Abnormal cases like that are treated as errors and handled by throwing an exception.

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

getRecordFromReference

public DataRecord getRecordFromReference(String reference)
                                  throws DataStoreException

Description copied from interface: DataStore

Returns the record that matches the given binary reference. Returns null if the reference is invalid, for example if it points to a record that does not exist.

Specified by:

getRecordFromReference in interface DataStore

Parameters:

reference - binary reference

Returns:

matching record, or null

Throws:

DataStoreException - if the data store could not be accessed

encodeHexString

protected static String encodeHexString(byte[] value)

Returns the hex encoding of the given bytes.

Parameters:

value - value to be encoded

Returns:

encoded value

getReferenceFromIdentifier

protected String getReferenceFromIdentifier(DataIdentifier identifier)

getOrCreateReferenceKey

protected byte[] getOrCreateReferenceKey()
                                  throws DataStoreException

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.

Returns:

reference key

Throws:

DataStoreException - if the key is not available