eventcenter.leveldb

类 QueueMiddleComponent

java.lang.Object

eventcenter.leveldb.QueueMiddleComponent

public class QueueMiddleComponent
extends Object

use read cursor and write cursor to store and read data, and create scheduling house-keeping to clear invalidate data

作者:

JackyLIU

字段概要

字段

限定符和类型	字段和说明
protected LevelDBPersistenceAdapter	adapter
protected LevelDBPage	currentPage
protected LevelDBCursor	deleteCursor pop a message wouldn't really delete a data, it just move deleteCursor, data would be deleted by house keeping
protected ReentrantLock	deleteLock when operating delete, it need to lock
protected Long	headPageNo
protected org.apache.log4j.Logger	logger
protected String	queueName
protected LevelDBCursor	readCursor
protected ReentrantLock	readLock when operating read , it need to lock
protected Long	rearPageNo
static long	THRESHOLD_SST_FILE_SIZE_OF_COMPACT 进行compact操作的sst文件大小阈值（100M）
protected LevelDBCursor	writeCursor
protected ReentrantLock	writeLock when operating write, it need to lock

构造器概要

构造器

构造器和说明
QueueMiddleComponent(LevelDBPersistenceAdapter adapter) create default queue named dq --> defaultQueue
QueueMiddleComponent(LevelDBPersistenceAdapter adapter, String queueName)

方法概要

限定符和类型	方法和说明
protected List<EventSourceWrapper>	_peek(int bulkSize)
protected void	batchDelete(long pageNo, int index, String... keys)
protected Long	calculateTotalCount()
void	clear()
void	close()
long	count()
<T> T	get(String key, Class<T> type)
protected org.iq80.leveldb.DB	getDB()
int	getPageSize()
String	getQueueName()
void	houseKeeping()
boolean	isOpenTxn()
void	load() load page info, read,write and delete cursor
protected void	loadCursor()
protected void	loadPage()
void	open()
EventSourceWrapper	peek() return the head data, but not move read cursor
List<EventSourceWrapper>	peek(int bulkSize)
EventSourceWrapper	pop() return the head data, and move read cursor ahead. if read cursor equals write cursor, it would return null.
List<EventSourceWrapper>	pop(int bulkSize)
List<EventSourceWrapper>	pop(int bulkSize, org.iq80.leveldb.WriteBatch wb) return a batch head data, and move read cursor ahead. if read cursor equals write cursor, it would return min size data.
EventSourceWrapper	pop(org.iq80.leveldb.WriteBatch wb)
long	popCount() 获取未被删除，但是已经pop的消息数量
protected void	put(String key, Serializable ser)
protected void	put(String key, Serializable ser, org.iq80.leveldb.WriteBatch update)
protected void	put(org.iq80.leveldb.WriteBatch wb, String key, Serializable ser)
String	save(CommonEventSource evt)
void	setOpenTxn(boolean openTxn)
void	setPageSize(int pageSize)
protected String	wrapperKey(String key)

从类继承的方法 java.lang.Object

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

字段详细资料

readCursor

protected volatile LevelDBCursor readCursor

writeCursor

protected volatile LevelDBCursor writeCursor

deleteCursor

protected volatile LevelDBCursor deleteCursor

pop a message wouldn't really delete a data, it just move deleteCursor, data would be deleted by house keeping

currentPage

protected volatile LevelDBPage currentPage

rearPageNo

protected volatile Long rearPageNo

headPageNo

protected volatile Long headPageNo

readLock

protected final ReentrantLock readLock

when operating read , it need to lock

writeLock

protected ReentrantLock writeLock

when operating write, it need to lock

deleteLock

protected ReentrantLock deleteLock

when operating delete, it need to lock

logger

protected final org.apache.log4j.Logger logger

adapter

protected final LevelDBPersistenceAdapter adapter

queueName

protected final String queueName

THRESHOLD_SST_FILE_SIZE_OF_COMPACT

public static final long THRESHOLD_SST_FILE_SIZE_OF_COMPACT

进行compact操作的sst文件大小阈值（100M）

另请参阅:

常量字段值

构造器详细资料

QueueMiddleComponent

public QueueMiddleComponent(LevelDBPersistenceAdapter adapter)

create default queue named dq --> defaultQueue

参数:

adapter -

QueueMiddleComponent

public QueueMiddleComponent(LevelDBPersistenceAdapter adapter,
                            String queueName)

方法详细资料

getDB

protected org.iq80.leveldb.DB getDB()

getQueueName

public String getQueueName()

getPageSize

public int getPageSize()

setPageSize

public void setPageSize(int pageSize)

open

public void open()
          throws IOException

抛出:

IOException

close

public void close()
           throws IOException

抛出:

IOException

load

public void load()
          throws PersistenceException

load page info, read,write and delete cursor

抛出:

PersistenceException

wrapperKey

protected String wrapperKey(String key)

isOpenTxn

public boolean isOpenTxn()

setOpenTxn

public void setOpenTxn(boolean openTxn)

get

public <T> T get(String key,
                 Class<T> type)
          throws PersistenceException

抛出:

PersistenceException

put

protected void put(String key,
                   Serializable ser)
            throws PersistenceException

抛出:

PersistenceException

put

protected void put(org.iq80.leveldb.WriteBatch wb,
                   String key,
                   Serializable ser)
            throws PersistenceException

抛出:

PersistenceException

put

protected void put(String key,
                   Serializable ser,
                   org.iq80.leveldb.WriteBatch update)
            throws PersistenceException

抛出:

PersistenceException

loadPage

protected void loadPage()
                 throws PersistenceException

抛出:

PersistenceException

loadCursor

protected void loadCursor()
                   throws PersistenceException

抛出:

PersistenceException

calculateTotalCount

protected Long calculateTotalCount()

save

public String save(CommonEventSource evt)
            throws PersistenceException

抛出:

PersistenceException

pop

public EventSourceWrapper pop()
                       throws PersistenceException

return the head data, and move read cursor ahead. if read cursor equals write cursor, it would return null.

返回:

抛出:

PersistenceException

pop

public EventSourceWrapper pop(org.iq80.leveldb.WriteBatch wb)
                       throws PersistenceException

抛出:

PersistenceException

pop

public List<EventSourceWrapper> pop(int bulkSize)
                             throws PersistenceException

抛出:

PersistenceException

pop

public List<EventSourceWrapper> pop(int bulkSize,
                                    org.iq80.leveldb.WriteBatch wb)
                             throws PersistenceException

return a batch head data, and move read cursor ahead. if read cursor equals write cursor, it would return min size data.

参数:

bulkSize -

返回:

抛出:

PersistenceException

peek

public EventSourceWrapper peek()
                        throws PersistenceException

return the head data, but not move read cursor

返回:

抛出:

PersistenceException

_peek

protected List<EventSourceWrapper> _peek(int bulkSize)
                                  throws PersistenceException

抛出:

PersistenceException

peek

public List<EventSourceWrapper> peek(int bulkSize)
                              throws PersistenceException

抛出:

PersistenceException

count

public long count()

popCount

public long popCount()

获取未被删除，但是已经pop的消息数量

返回:

houseKeeping

public void houseKeeping()
                  throws PersistenceException

抛出:

PersistenceException

batchDelete

protected void batchDelete(long pageNo,
                           int index,
                           String... keys)
                    throws PersistenceException

抛出:

PersistenceException

clear

public void clear()
           throws Exception

抛出:

Exception