RocksDbQueue (ddth-queue-core 0.4.2 API)

java.lang.Object
- com.github.ddth.queue.impl.RocksDbQueue

All Implemented Interfaces:

IQueue, Closeable, AutoCloseable

Direct Known Subclasses:

BaseUniversalRocksDbQueue
```
public abstract class RocksDbQueue
extends Object
implements IQueue, Closeable, AutoCloseable
```
RocksDB implementation of IQueue.
Implementation:
- RocksDB as queue storage
Since:

0.4.0

Author:

Thanh Ba Nguyen

Constructor Summary

Constructors
Constructor and Description

RocksDbQueue()

Constructors
Constructor and Description
`RocksDbQueue()`

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`close()`
`protected abstract IQueueMessage`	`deserialize(byte[] msgData)` Deserilizes a queue message.
`void`	`destroy()` Destroy method.
`int`	`ephemeralSize()` Gets ephemeral-storage's number of items.
`void`	`finish(IQueueMessage msg)` Called when finish processing the message to cleanup ephemeral storage.
`protected org.rocksdb.ColumnFamilyHandle`	`getCfEphemeral()`
`protected org.rocksdb.ColumnFamilyHandle`	`getCfMetadata()`
`String`	`getCfNameEphemeral()` Name of the ColumnFamily to store ephemeral messages.
`String`	`getCfNameMetadata()` Name of the ColumnFamily to store metadata.
`String`	`getCfNameQueue()` Name of the ColumnFamily to store queue messages.
`protected org.rocksdb.ColumnFamilyHandle`	`getCfQueue()`
`boolean`	`getEphemeralDisabled()` Is ephemeral storage disabled?
`Collection<IQueueMessage>`	`getOrphanMessages(long thresholdTimestampMs)` Gets all orphan messages (messages that were left in ephemeral storage for a long time).
`protected org.rocksdb.ReadOptions`	`getReadOptions()`
`protected org.rocksdb.RocksDB`	`getRocksDb()`
`String`	`getStorageDir()` RocksDB's storage directory.
`protected org.rocksdb.WriteOptions`	`getWriteOptions()`
`RocksDbQueue`	`init()` Init method.
`boolean`	`isEphemeralDisabled()` Is ephemeral storage disabled?
`boolean`	`moveFromEphemeralToQueueStorage(IQueueMessage msg)` Moves a message from ephemeral back to queue storage.
`protected boolean`	`putToQueue(IQueueMessage msg, boolean removeFromEphemeral)`
`boolean`	`queue(IQueueMessage _msg)` Queues a message.
`int`	`queueSize()` Gets queue's number of items.
`boolean`	`requeue(IQueueMessage _msg)` Re-queues a message.
`boolean`	`requeueSilent(IQueueMessage msg)` Silently re-queues a message.
`protected abstract byte[]`	`serialize(IQueueMessage msg)` Serializes a queue message to byte[].
`RocksDbQueue`	`setCfNameEphemeral(String cfNameEphemeral)` Sets name of the ColumnFamily to store ephemeral messages.
`RocksDbQueue`	`setCfNameMetadata(String cfNameMetadata)` Sets name of the ColumnFamily to store metadata.
`RocksDbQueue`	`setCfNameQueue(String cfNameQueue)` Sets name of the ColumnFamily to store queue messages.
`RocksDbQueue`	`setEphemeralDisabled(boolean ephemeralDisabled)` Disables/Enables ephemeral storage.
`RocksDbQueue`	`setStorageDir(String storageDir)` Sets RocksDB's storage directory.
`IQueueMessage`	`take()` Takes a message out of queue.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - RocksDbQueue
```
public RocksDbQueue()
```
- Method Detail
  - getRocksDb
```
protected org.rocksdb.RocksDB getRocksDb()
```
    Returns:
    
    Since:
    
    0.4.0.1
  - getCfQueue
```
protected org.rocksdb.ColumnFamilyHandle getCfQueue()
```
    Returns:
    
    Since:
    
    0.4.0.1
  - getCfMetadata
```
protected org.rocksdb.ColumnFamilyHandle getCfMetadata()
```
    Returns:
    
    Since:
    
    0.4.0.1
  - getCfEphemeral
```
protected org.rocksdb.ColumnFamilyHandle getCfEphemeral()
```
    Returns:
    
    Since:
    
    0.4.0.1
  - getReadOptions
```
protected org.rocksdb.ReadOptions getReadOptions()
```
    Returns:
    
    Since:
    
    0.4.0.1
  - getWriteOptions
```
protected org.rocksdb.WriteOptions getWriteOptions()
```
    Returns:
    
    Since:
    
    0.4.0.1
  - getEphemeralDisabled
```
public boolean getEphemeralDisabled()
```
    Is ephemeral storage disabled?
    
    Returns:
    
    Since:
    
    0.4.0.1
  - isEphemeralDisabled
```
public boolean isEphemeralDisabled()
```
    Is ephemeral storage disabled?
    
    Returns:
    
    Since:
    
    0.4.0.1
  - setEphemeralDisabled
```
public RocksDbQueue setEphemeralDisabled(boolean ephemeralDisabled)
```
    Disables/Enables ephemeral storage.
    
    Parameters:
    
    ephemeralDisabled - true to disable ephemeral storage, false otherwise.
    
    Returns:
    
    Since:
    
    0.4.0.1
  - getStorageDir
```
public String getStorageDir()
```
    RocksDB's storage directory.
    
    Returns:
  - setStorageDir
```
public RocksDbQueue setStorageDir(String storageDir)
```
    Sets RocksDB's storage directory.
    
    Parameters:
    
    storageDir -
    
    Returns:
  - getCfNameQueue
```
public String getCfNameQueue()
```
    Name of the ColumnFamily to store queue messages.
    
    Returns:
    
    Since:
    
    0.4.0.1
  - setCfNameQueue
```
public RocksDbQueue setCfNameQueue(String cfNameQueue)
```
    Sets name of the ColumnFamily to store queue messages.
    
    Parameters:
    
    cfNameQueue -
    
    Returns:
    
    Since:
    
    0.4.0.1
  - getCfNameMetadata
```
public String getCfNameMetadata()
```
    Name of the ColumnFamily to store metadata.
    
    Returns:
    
    Since:
    
    0.4.0.1
  - setCfNameMetadata
```
public RocksDbQueue setCfNameMetadata(String cfNameMetadata)
```
    Sets name of the ColumnFamily to store metadata.
    
    Parameters:
    
    cfNameMetadata -
    
    Returns:
    
    Since:
    
    0.4.0.1
  - getCfNameEphemeral
```
public String getCfNameEphemeral()
```
    Name of the ColumnFamily to store ephemeral messages.
    
    Returns:
    
    Since:
    
    0.4.0.1
  - setCfNameEphemeral
```
public RocksDbQueue setCfNameEphemeral(String cfNameEphemeral)
```
    Sets name of the ColumnFamily to store ephemeral messages.
    
    Parameters:
    
    cfNameEphemeral -
    
    Returns:
    
    Since:
    
    0.4.0.1
  - init
```
public RocksDbQueue init()
```
    Init method.
    
    Returns:
  - destroy
```
public void destroy()
```
    Destroy method.
  - close
```
public void close()
```
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
  - serialize
```
protected abstract byte[] serialize(IQueueMessage msg)
```
    Serializes a queue message to byte[].
    
    Parameters:
    
    msg -
    
    Returns:
  - deserialize
```
protected abstract IQueueMessage deserialize(byte[] msgData)
```
    Deserilizes a queue message.
    
    Parameters:
    
    msgData -
    
    Returns:
  - putToQueue
```
protected boolean putToQueue(IQueueMessage msg,
                             boolean removeFromEphemeral)
```
  - queue
```
public boolean queue(IQueueMessage _msg)
```
    Queues a message.
    Implementation flow:
    - Put message to tail of queue storage.
    Specified by:
    
    queue in interface IQueue
    
    Returns:
  - requeue
```
public boolean requeue(IQueueMessage _msg)
```
    Re-queues a message.
    Implementation flow:
    - Put message to tail of queue storage; and increase message's re-queue count & update message's queue timestamp.
    - Remove message from ephemeral storage.
    Note: ephemeral storage implementation is optional, depends on implementation.
    Specified by:
    
    requeue in interface IQueue
    
    Returns:
  - requeueSilent
```
public boolean requeueSilent(IQueueMessage msg)
```
    Silently re-queues a message.
    Implementation flow:
    - Put message to tail of queue storage; do NOT increase message's re-queue count and do NOT update message's queue timestamp.
    - Remove message from ephemeral storage.
    Note: ephemeral storage implementation is optional, depends on implementation.
    Specified by:
    
    requeueSilent in interface IQueue
    
    Returns:
  - finish
```
public void finish(IQueueMessage msg)
```
    Called when finish processing the message to cleanup ephemeral storage.
    Implementation flow:
    - Remove message from ephemeral storage.
    Note: ephemeral storage implementation is optional, depends on implementation.
    Specified by:
    
    finish in interface IQueue
  - take
```
public IQueueMessage take()
```
    Takes a message out of queue.
    Implementation flow:
    - Read message from head of queue storage.
    - Write message to ephemeral storage.
    - Remove message from queue storage.
    Note: ephemeral storage implementation is optional, depends on implementation.
    Specified by:
    
    take in interface IQueue
    
    Returns:
  - getOrphanMessages
```
public Collection<IQueueMessage> getOrphanMessages(long thresholdTimestampMs)
```
    Gets all orphan messages (messages that were left in ephemeral storage for a long time).
    
    Specified by:
    
    getOrphanMessages in interface IQueue
    
    Parameters:
    
    thresholdTimestampMs -
    
    Returns:
  - moveFromEphemeralToQueueStorage
```
public boolean moveFromEphemeralToQueueStorage(IQueueMessage msg)
```
    Moves a message from ephemeral back to queue storage. Useful when dealing with orphan messages.
    Implementation flow:
    - Read message from the ephemeral storage.
    - Put the message back to queue.
    - Remove the message from the ephemeral storage.
    Specified by:
    
    moveFromEphemeralToQueueStorage in interface IQueue
    
    Returns:
    
    true if a move has been made, false otherwise (e.g. the message didn't exist in ephemeral storage)
  - queueSize
```
public int queueSize()
```
    Gets queue's number of items.
    
    Specified by:
    
    queueSize in interface IQueue
    
    Returns:
  - ephemeralSize
```
public int ephemeralSize()
```
    Gets ephemeral-storage's number of items.
    Note: ephemeral storage implementation is optional, depends on implementation.
    
    Specified by:
    
    ephemeralSize in interface IQueue
    
    Returns:

Class RocksDbQueue

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

RocksDbQueue

Method Detail

getRocksDb

getCfQueue

getCfMetadata

getCfEphemeral

getReadOptions

getWriteOptions

getEphemeralDisabled

isEphemeralDisabled

setEphemeralDisabled

getStorageDir

setStorageDir

getCfNameQueue

setCfNameQueue

getCfNameMetadata

setCfNameMetadata

getCfNameEphemeral

setCfNameEphemeral

init

destroy

close

serialize

deserialize

putToQueue

queue

requeue

requeueSilent

finish

take

getOrphanMessages

moveFromEphemeralToQueueStorage

queueSize

ephemeralSize