org.apache.directory.mavibot.btree

Class InMemoryBTree<K,V>

java.lang.Object

org.apache.directory.mavibot.btree.AbstractBTree<K,V>

org.apache.directory.mavibot.btree.InMemoryBTree<K,V>

Type Parameters:

K - The type for the keys

V - The type for the stored values

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, BTree<K,V>

class InMemoryBTree<K,V>
extends AbstractBTree<K,V>
implements java.io.Closeable

The B+Tree MVCC data structure.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	DATA_SUFFIX The default data file suffix
static java.lang.String	DEFAULT_JOURNAL The default journal name
private java.io.File	envDir The directory where the journal will be stored
private java.io.File	file The associated file.
private java.io.File	journal The associated journal.
static java.lang.String	JOURNAL_SUFFIX The default journal file suffix
private java.nio.channels.FileChannel	journalChannel The Journal channel
protected static org.slf4j.Logger	LOG The LoggerFactory used by this class
private boolean	withJournal A flag used to tell the BTree that the journal is activated

Fields inherited from class org.apache.directory.mavibot.btree.AbstractBTree

allowDuplicates, btreeRevisions, btreeType, currentBtreeHeader, currentRevision, keySerializer, keySerializerFQCN, name, pageSize, readTimeOut, readTransactions, readTransactionsThread, transactionManager, transactionStarted, valueSerializer, valueSerializerFQCN, writeBufferSize

Fields inherited from interface org.apache.directory.mavibot.btree.BTree

ALLOW_DUPLICATES, DEFAULT_PAGE_SIZE, DEFAULT_READ_TIMEOUT, DEFAULT_WRITE_BUFFER_SIZE, FORBID_DUPLICATES

Constructor Summary

Constructors

Constructor and Description
InMemoryBTree() Creates a new BTree, with no initialization.
InMemoryBTree(InMemoryBTreeConfiguration<K,V> configuration) Creates a new in-memory BTree using the BTreeConfiguration to initialize the BTree

Method Summary

Modifier and Type	Method and Description
private void	applyJournal() Inject all the modification from the journal into the btree
protected ReadTransaction<K,V>	beginReadTransaction() Starts a Read Only transaction.
protected ReadTransaction<K,V>	beginReadTransaction(long revision) Starts a Read Only transaction.
void	close() Close the BTree, cleaning up all the data structure
private BTreeHeader<K,V>	createNewBtreeHeader(BTreeHeader<K,V> btreeHeader, long revision) Create a new B-tree header to be used for update operations
protected Tuple<K,V>	delete(K key, V value, long revision) Deletes the given pair if both key and value match.
void	flush() Flush the latest revision to disk.
void	flush(java.io.File file) Flush the latest revision to disk
java.io.File	getFile()
java.io.File	getJournal()
Page<K,V>	getRootPage() Get the current rootPage
Page<K,V>	getRootPage(long revision) Get the rootPage associated to a give revision.
private void	init() Initialize the BTree.
(package private) InsertResult<K,V>	insert(K key, V value, long revision) Insert an entry in the BTree.
boolean	isInMemory()
boolean	isPersistent()
void	load(java.io.File file) Read the data from the disk into this BTree.
void	setFilePath(java.lang.String filePath) Set the file path where the journal will be stored
(package private) void	setRootPage(Page<K,V> root)
java.lang.String	toString()
private void	writeBuffer(java.nio.channels.FileChannel channel, java.nio.ByteBuffer bb, byte[] buffer) Write the data in the ByteBuffer, and eventually on disk if needed.
private void	writeToJournal(Modification<K,V> modification)

Methods inherited from class org.apache.directory.mavibot.btree.AbstractBTree

browse, browse, browseFrom, browseFrom, browseKeys, contains, contains, createTransactionManager, delete, delete, delete, get, get, getBtreeHeader, getBtreeHeader, getKeyComparator, getKeySerializer, getKeySerializerFQCN, getName, getNbElems, getPageSize, getReadTimeOut, getRevision, getType, getValueComparator, getValues, getValueSerializer, getValueSerializerFQCN, getWriteBufferSize, hasKey, hasKey, insert, isAllowDuplicates, setAllowDuplicates, setKeySerializer, setName, setNbElems, setPageSize, setReadTimeOut, setRevision, setType, setValueSerializer, setWriteBufferSize, storeRevision, storeRevision

Methods inherited from class java.lang.Object

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

Field Detail

LOG

protected static final org.slf4j.Logger LOG

The LoggerFactory used by this class

DEFAULT_JOURNAL

public static final java.lang.String DEFAULT_JOURNAL

The default journal name

See Also:

Constant Field Values

DATA_SUFFIX

public static final java.lang.String DATA_SUFFIX

The default data file suffix

See Also:

Constant Field Values

JOURNAL_SUFFIX

public static final java.lang.String JOURNAL_SUFFIX

The default journal file suffix

See Also:

Constant Field Values

file

private java.io.File file

The associated file. If null, this is an in-memory btree

withJournal

private boolean withJournal

A flag used to tell the BTree that the journal is activated

journal

private java.io.File journal

The associated journal. If null, this is an in-memory btree

envDir

private java.io.File envDir

The directory where the journal will be stored

journalChannel

private java.nio.channels.FileChannel journalChannel

The Journal channel

Constructor Detail

InMemoryBTree

InMemoryBTree()

Creates a new BTree, with no initialization.

InMemoryBTree

InMemoryBTree(InMemoryBTreeConfiguration<K,V> configuration)

Creates a new in-memory BTree using the BTreeConfiguration to initialize the BTree

Parameters:

configuration - The configuration to use

Method Detail

init

private void init()
           throws java.io.IOException

Initialize the BTree.

Throws:

java.io.IOException - If we get some exception while initializing the BTree

beginReadTransaction

protected ReadTransaction<K,V> beginReadTransaction()

Starts a Read Only transaction. If the transaction is not closed, it will be automatically closed after the timeout

Specified by:

beginReadTransaction in class AbstractBTree<K,V>

Returns:

The created transaction

beginReadTransaction

protected ReadTransaction<K,V> beginReadTransaction(long revision)

Starts a Read Only transaction. If the transaction is not closed, it will be automatically closed after the timeout

Specified by:

beginReadTransaction in class AbstractBTree<K,V>

Returns:

The created transaction

close

public void close()
           throws java.io.IOException

Close the BTree, cleaning up all the data structure

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface BTree<K,V>

Throws:

java.io.IOException

delete

protected Tuple<K,V> delete(K key,
                            V value,
                            long revision)
                     throws java.io.IOException

Deletes the given pair if both key and value match. If the given value is null and there is no null value associated with the given key then the entry with the given key will be removed.

Specified by:

delete in class AbstractBTree<K,V>

Parameters:

key - The key to be removed

value - The value to be removed (can be null, and when no null value exists the key will be removed irrespective of the value)

revision - The revision to be associated with this operation

Returns:

Throws:

java.io.IOException

insert

InsertResult<K,V> insert(K key,
                         V value,
                         long revision)
                  throws java.io.IOException

Insert an entry in the BTree.

We will replace the value if the provided key already exists in the btree.

The revision number is the revision to use to insert the data.

Specified by:

insert in class AbstractBTree<K,V>

Parameters:

key - Inserted key

value - Inserted value

revision - The revision to use

Returns:

an instance of the InsertResult.

Throws:

java.io.IOException

writeBuffer

private void writeBuffer(java.nio.channels.FileChannel channel,
                         java.nio.ByteBuffer bb,
                         byte[] buffer)
                  throws java.io.IOException

Write the data in the ByteBuffer, and eventually on disk if needed.

Parameters:

channel - The channel we want to write to

bb - The ByteBuffer we want to feed

buffer - The data to inject

Throws:

java.io.IOException - If the write failed

flush

public void flush(java.io.File file)
           throws java.io.IOException

Flush the latest revision to disk

Parameters:

file - The file into which the data will be written

Throws:

java.io.IOException

applyJournal

private void applyJournal()
                   throws java.io.IOException

Inject all the modification from the journal into the btree

Throws:

java.io.IOException - If we had some issue while reading the journal

load

public void load(java.io.File file)
          throws java.io.IOException

Read the data from the disk into this BTree. All the existing data in the BTree are kept, the read data will be associated with a new revision.

Parameters:

file -

Throws:

java.io.IOException

getRootPage

public Page<K,V> getRootPage(long revision)
                      throws java.io.IOException,
                             KeyNotFoundException

Get the rootPage associated to a give revision.

Specified by:

getRootPage in interface BTree<K,V>

Parameters:

revision - The revision we are looking for

Returns:

The rootPage associated to this revision

Throws:

java.io.IOException - If we had an issue while accessing the underlying file

KeyNotFoundException - If the revision does not exist for this Btree

getRootPage

public Page<K,V> getRootPage()

Get the current rootPage

Specified by:

getRootPage in interface BTree<K,V>

Specified by:

getRootPage in class AbstractBTree<K,V>

Returns:

The rootPage

setRootPage

void setRootPage(Page<K,V> root)

Description copied from class: AbstractBTree

Specified by:

setRootPage in class AbstractBTree<K,V>

flush

public void flush()
           throws java.io.IOException

Flush the latest revision to disk. We will replace the current file by the new one, as we flush in a temporary file.

Specified by:

flush in interface BTree<K,V>

Overrides:

flush in class AbstractBTree<K,V>

Throws:

java.io.IOException

getFile

public java.io.File getFile()

Returns:

the file

setFilePath

public void setFilePath(java.lang.String filePath)

Set the file path where the journal will be stored

Parameters:

filePath - The file path

getJournal

public java.io.File getJournal()

Returns:

the journal

isInMemory

public boolean isInMemory()

Returns:

true if the BTree is fully in memory

isPersistent

public boolean isPersistent()

Returns:

true if the BTree is persisted on disk

writeToJournal

private void writeToJournal(Modification<K,V> modification)
                     throws java.io.IOException

Throws:

java.io.IOException

createNewBtreeHeader

private BTreeHeader<K,V> createNewBtreeHeader(BTreeHeader<K,V> btreeHeader,
                                              long revision)

Create a new B-tree header to be used for update operations

Parameters:

revision - The reclaimed revision

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

See Also:

Object.toString()