nl.renarj.jasdb.core.storage

Interface RecordWriter

All Known Implementing Classes:

BtreeIndexRecordWriter, CachedRecordWriter, TransactionalRecordWriter

public interface RecordWriter

This is the interface that any record writers need to implement. Main goal of any record writer is to persist data streams to a persistent storage medium. Any guarantees about transactionality, disk flushing strategy is up to the implementation of the record writer.

Author:

Renze de Vries

Method Summary

Modifier and Type	Method and Description
void	closeWriter() This closes the writer channel and releases all the resources
void	flush() Guarantees the changes are flushed to the disk
long	getDiskSize() Gets the disk size of the persistence storage
long	getSize() Gets the amount of data streams / records stored
boolean	isOpen() Checks if the writer is already open
void	openWriter() This opens the writer for all access, needs to be done before any operations are done on the recordwriter
RecordIterator	readAllRecords() This returns an iterator that can iterate over all persisted records.
RecordIterator	readAllRecords(int limit) This returns an iterator that can iterate over all persisted records to a defined limit.
RecordResult	readRecord(UUIDKey documentId) This reads a specific record at the indicated record position
void	removeRecord(UUIDKey documentId) This will command the writer to remove the indicated record from storage.
void	updateRecord(UUIDKey documentId, ClonableDataStream dataStream) This updates the record contents stored in storage for a given updated content and the current record pointer to the record.
void	writeRecord(UUIDKey documentId, ClonableDataStream dataStream) This writes the given content to the filesystem and returns the record pointer at which the record can be retrieved on next attempt.

Method Detail

getDiskSize

long getDiskSize()
          throws JasDBStorageException

Gets the disk size of the persistence storage

Returns:

The disksize in bytes

Throws:

JasDBStorageException - If unable to get the disksize

getSize

long getSize()
      throws JasDBStorageException

Gets the amount of data streams / records stored

Returns:

The amount of datastreams / records stored

Throws:

JasDBStorageException - If unable to get the size

openWriter

void openWriter()
         throws JasDBStorageException

This opens the writer for all access, needs to be done before any operations are done on the recordwriter

Throws:

JasDBStorageException - If unable to open the writer

closeWriter

void closeWriter()
          throws JasDBStorageException

This closes the writer channel and releases all the resources

Throws:

JasDBStorageException - If unable to close the writer

flush

void flush()
    throws JasDBStorageException

Guarantees the changes are flushed to the disk

Throws:

JasDBStorageException - If unable to flush changes to the disk

isOpen

boolean isOpen()

Checks if the writer is already open

Returns:

True if the writer is open and ready for usage, False if not

readAllRecords

RecordIterator readAllRecords()
                       throws JasDBStorageException

This returns an iterator that can iterate over all persisted records.

Returns:

The record iterator which can iterate over all the persisted record.

Throws:

JasDBStorageException - If unable to return an iterator, channel is closed or not accessible

readAllRecords

RecordIterator readAllRecords(int limit)
                       throws JasDBStorageException

This returns an iterator that can iterate over all persisted records to a defined limit.

Returns:

The record iterator which can iterate over all the persisted record to a defined limit.

Throws:

JasDBStorageException - If unable to return an iterator, channel is closed or not accessible

readRecord

RecordResult readRecord(UUIDKey documentId)
                 throws JasDBStorageException

This reads a specific record at the indicated record position

Parameters:

documentId - The document key identifier used to identify the document to write to storage

Returns:

The RecordResult if the record could be found

Throws:

JasDBStorageException - In case the record could not be found or read

writeRecord

void writeRecord(UUIDKey documentId,
                 ClonableDataStream dataStream)
          throws JasDBStorageException

This writes the given content to the filesystem and returns the record pointer at which the record can be retrieved on next attempt.

Parameters:

documentId - The document key identifier used to identify the document to write to storage

dataStream - The datastream to be written to storage

Throws:

JasDBStorageException - If unable to write the record to the storage

removeRecord

void removeRecord(UUIDKey documentId)
           throws JasDBStorageException

This will command the writer to remove the indicated record from storage.

Parameters:

documentId - The document key identifier used to identify the document to remove

Throws:

JasDBStorageException - If unable to find the indicated record or removing failed.

updateRecord

void updateRecord(UUIDKey documentId,
                  ClonableDataStream dataStream)
           throws JasDBStorageException

This updates the record contents stored in storage for a given updated content and the current record pointer to the record. It will return the same or an updated record pointer pointing to the updated content on the disk.

Parameters:

documentId - The document key identifier used to identify the document to write to storage

dataStream - The datastream to be written to storage

Throws:

JasDBStorageException - If unable to update in case no record exists or unable to update in storage.