OHCacher (moleculer-java 1.2.21 API)

java.lang.Object
- services.moleculer.service.MoleculerComponent
- - services.moleculer.service.Middleware
  - - services.moleculer.cacher.Cacher
    - - services.moleculer.cacher.OHCacher

All Implemented Interfaces:

MetricConstants, MoleculerLifecycle
```
public class OHCacher
extends Cacher
```
Off-heap cache implementation (it's similar to MemoryCacher, but stores entries in the off-heap RAM). Supports global and entry-level TTL configuration. See this gitHub project for a more description: https://github.com/snazy/ohc.
Configuration properties:
- ttl: expire time of entries in memory, in seconds (default: 0 = never expires)
- capacity: capacity for data over the whole cache in MEGABYTES
- segmentCount: number of segments (must be a power of 2), defaults to number-of-cores * 2
- hashTableSize: hash table size (must be a power of 2), defaults to 8192
- compressAbove: compress key and/or value above this size (BYTES)
Performance (per thread / core):

Small uncompressed data
In SMILE format: 392 000 gets / second
In JSON format: 380 000 gets / second

Compressed large data in 20% compression ratio
In SMILE format: 20 000 gets / second
In JSON format: 16 000 gets / second

This cache is fundamentally slower than MemoryCacher, but it can store compressed entries in the off-heap RAM. OHCacher is the solution to store huge amount of data in memory; if you plan to store few thousands (or less) entries in the cache, use the faster MemoryCacher, otherwise use OHCacher.

Required dependency:

// https://mvnrepository.com/artifact/org.caffinitas.ohc/ohc-core-j8
compile group: 'org.caffinitas.ohc', name: 'ohc-core-j8', version: '0.6.1'
See Also:

MemoryCacher, RedisCacher

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

protected static class OHCacher.ArraySerializer

Nested Classes
Modifier and Type	Class and Description
`protected static class`	`OHCacher.ArraySerializer`

Field Summary

Fields
Modifier and Type	Field and Description
`protected org.caffinitas.ohc.OHCache<byte[],byte[]>`	`cache`
`protected long`	`capacity` Maximum capacity of whole cache in MEGABYTES
`protected int`	`compressAbove` Compress key and/or value above this size (BYTES), 0 = disable compression
`protected int`	`compressionLevel` Compression level (best speed = 1, best compression = 9)
`protected static java.lang.String`	`CONTENT`
`protected MetricCounter`	`counterClean`
`protected MetricCounter`	`counterDel`
`protected MetricCounter`	`counterFound`
`protected MetricCounter`	`counterGet`
`protected MetricCounter`	`counterSet`
`protected MetricGauge`	`gaugeExpired`
`protected int`	`hashTableSize` Hash table size (must be a power of 2), defaults to 8192
`protected int`	`segmentCount` Number of segments (must be a power of 2), defaults to number-of-cores * 2
`protected Serializer`	`serializer`
`protected java.util.concurrent.ScheduledFuture<?>`	`timer` Cancelable timer
`protected int`	`ttl` Expire time, in seconds (0 = never expires)

Fields inherited from class services.moleculer.cacher.Cacher
metrics

Fields inherited from class services.moleculer.service.MoleculerComponent
broker, logger, name

Fields inherited from interface services.moleculer.metrics.MetricConstants
MOLECULER_CACHER_CLEAN_TIME, MOLECULER_CACHER_CLEAN_TIME_DESC, MOLECULER_CACHER_CLEAN_TOTAL, MOLECULER_CACHER_CLEAN_TOTAL_DESC, MOLECULER_CACHER_DEL_TIME, MOLECULER_CACHER_DEL_TIME_DESC, MOLECULER_CACHER_DEL_TOTAL, MOLECULER_CACHER_DEL_TOTAL_DESC, MOLECULER_CACHER_EXPIRED_TOTAL, MOLECULER_CACHER_EXPIRED_TOTAL_DESC, MOLECULER_CACHER_FOUND_TOTAL, MOLECULER_CACHER_FOUND_TOTAL_DESC, MOLECULER_CACHER_GET_TIME, MOLECULER_CACHER_GET_TIME_DESC, MOLECULER_CACHER_GET_TOTAL, MOLECULER_CACHER_GET_TOTAL_DESC, MOLECULER_CACHER_SET_TIME, MOLECULER_CACHER_SET_TIME_DESC, MOLECULER_CACHER_SET_TOTAL, MOLECULER_CACHER_SET_TOTAL_DESC, MOLECULER_CIRCUIT_BREAKER_HALF_OPENED_ACTIVE, MOLECULER_CIRCUIT_BREAKER_HALF_OPENED_ACTIVE_DESC, MOLECULER_CIRCUIT_BREAKER_OPENED_ACTIVE, MOLECULER_CIRCUIT_BREAKER_OPENED_ACTIVE_DESC, MOLECULER_CIRCUIT_BREAKER_OPENED_TOTAL, MOLECULER_CIRCUIT_BREAKER_OPENED_TOTAL_DESC, MOLECULER_EVENT_BROADCAST_TOTAL, MOLECULER_EVENT_BROADCAST_TOTAL_DESC, MOLECULER_EVENT_BROADCASTLOCAL_TOTAL, MOLECULER_EVENT_BROADCASTLOCAL_TOTAL_DESC, MOLECULER_EVENT_EMIT_TOTAL, MOLECULER_EVENT_EMIT_TOTAL_DESC, MOLECULER_EVENT_RECEIVED_ACTIVE, MOLECULER_EVENT_RECEIVED_ACTIVE_DESC, MOLECULER_EVENT_RECEIVED_ERROR_TOTAL, MOLECULER_EVENT_RECEIVED_ERROR_TOTAL_DESC, MOLECULER_EVENT_RECEIVED_TIME, MOLECULER_EVENT_RECEIVED_TIME_DESC, MOLECULER_EVENT_RECEIVED_TOTAL, MOLECULER_EVENT_RECEIVED_TOTAL_DESC, MOLECULER_EXECUTOR, MOLECULER_REQUEST_ACTIVE, MOLECULER_REQUEST_ACTIVE_DESC, MOLECULER_REQUEST_ERROR_TOTAL, MOLECULER_REQUEST_ERROR_TOTAL_DESC, MOLECULER_REQUEST_LEVELS, MOLECULER_REQUEST_LEVELS_DESC, MOLECULER_REQUEST_RETRY_ATTEMPTS_TOTAL, MOLECULER_REQUEST_RETRY_ATTEMPTS_TOTAL_DESC, MOLECULER_REQUEST_TIME, MOLECULER_REQUEST_TIME_DESC, MOLECULER_REQUEST_TIMEOUT_TOTAL, MOLECULER_REQUEST_TIMEOUT_TOTAL_DESC, MOLECULER_REQUEST_TOTAL, MOLECULER_REQUEST_TOTAL_DESC, MOLECULER_SCHEDULER, MOLECULER_TRANSIT_CONNECTED, MOLECULER_TRANSIT_CONNECTED_DESC, MOLECULER_TRANSIT_ORPHAN_RESPONSE_TOTAL, MOLECULER_TRANSIT_ORPHAN_RESPONSE_TOTAL_DESC, MOLECULER_TRANSIT_REQUESTS_ACTIVE, MOLECULER_TRANSIT_REQUESTS_ACTIVE_DESC, MOLECULER_TRANSIT_STREAMS_RECEIVE_ACTIVE, MOLECULER_TRANSIT_STREAMS_RECEIVE_ACTIVE_DESC, MOLECULER_TRANSPORTER_PACKETS_RECEIVED_BYTES, MOLECULER_TRANSPORTER_PACKETS_RECEIVED_BYTES_DESC, MOLECULER_TRANSPORTER_PACKETS_RECEIVED_TOTAL, MOLECULER_TRANSPORTER_PACKETS_RECEIVED_TOTAL_DESC, MOLECULER_TRANSPORTER_PACKETS_SENT_BYTES, MOLECULER_TRANSPORTER_PACKETS_SENT_BYTES_DESC, MOLECULER_TRANSPORTER_PACKETS_SENT_TOTAL, MOLECULER_TRANSPORTER_PACKETS_SENT_TOTAL_DESC

Constructor Summary

Constructors
Constructor and Description
`OHCacher()` Creates Off-heap Cacher with the default settings.
`OHCacher(long maxCapacity, int defaultTtl)` Creates Off-heap Cacher.
`OHCacher(long maxCapacity, int defaultTtl, int segmentCount, int hashTableSize, int compressAbove)` Creates Off-heap Cacher.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`protected java.lang.String`	`bytesToKey(byte[] bytes)`
`protected io.datatree.Tree`	`bytesToValue(byte[] bytes)`
`io.datatree.Promise`	`clean(java.lang.String match)` Cleans this cache.
`io.datatree.Promise`	`del(java.lang.String key)` Deletes a content from this cache.
`io.datatree.Promise`	`get(java.lang.String key)` Gets a cached content by a key.
`io.datatree.Promise`	`getCacheKeys()` Lists all keys of cached entries.
`long`	`getCapacity()`
`int`	`getCompressAbove()`
`int`	`getCompressionLevel()`
`int`	`getHashTableSize()`
`int`	`getSegmentCount()`
`Serializer`	`getSerializer()`
`int`	`getTtl()`
`protected byte[]`	`keyToBytes(java.lang.String key)`
`io.datatree.Promise`	`set(java.lang.String key, io.datatree.Tree value, int ttl)` Sets a content by key into the cache.
`void`	`setCapacity(long capacity)`
`void`	`setCompressAbove(int compressAbove)`
`void`	`setCompressionLevel(int compressionLevel)`
`void`	`setHashTableSize(int hashTableSize)`
`void`	`setSegmentCount(int segmentCount)`
`void`	`setSerializer(Serializer serializer)`
`void`	`setTtl(int ttl)`
`void`	`started(ServiceBroker broker)` Initializes cacher instance.
`void`	`stopped()`
`protected byte[]`	`valueToBytes(io.datatree.Tree tree)`

Methods inherited from class services.moleculer.cacher.Cacher
appendToKey, appendTree, getCacheKey, install, isCachingDisabledByTheContext, serializeKey

Methods inherited from class services.moleculer.service.MoleculerComponent
getBroker, getLogger, getName

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

- Field Detail
  - CONTENT
```
protected static final java.lang.String CONTENT
```
    See Also:
    
    Constant Field Values
  - capacity
```
protected long capacity
```
    Maximum capacity of whole cache in MEGABYTES
  - segmentCount
```
protected int segmentCount
```
    Number of segments (must be a power of 2), defaults to number-of-cores * 2
  - hashTableSize
```
protected int hashTableSize
```
    Hash table size (must be a power of 2), defaults to 8192
  - ttl
```
protected int ttl
```
    Expire time, in seconds (0 = never expires)
  - compressAbove
```
protected int compressAbove
```
    Compress key and/or value above this size (BYTES), 0 = disable compression
  - compressionLevel
```
protected int compressionLevel
```
    Compression level (best speed = 1, best compression = 9)
  - serializer
```
protected Serializer serializer
```
  - cache
```
protected org.caffinitas.ohc.OHCache<byte[],byte[]> cache
```
  - timer
```
protected volatile java.util.concurrent.ScheduledFuture<?> timer
```
    Cancelable timer
  - gaugeExpired
```
protected MetricGauge gaugeExpired
```
  - counterGet
```
protected MetricCounter counterGet
```
  - counterSet
```
protected MetricCounter counterSet
```
  - counterDel
```
protected MetricCounter counterDel
```
  - counterClean
```
protected MetricCounter counterClean
```
  - counterFound
```
protected MetricCounter counterFound
```
- Constructor Detail
  - OHCacher
```
public OHCacher()
```
    Creates Off-heap Cacher with the default settings.
  - OHCacher
```
public OHCacher(long maxCapacity,
                int defaultTtl)
```
    Creates Off-heap Cacher.
    
    Parameters:
    
    maxCapacity - capacity for data over the whole cache in MEGABYTES
    
    defaultTtl - expire time of entries in memory, in seconds (default: 0 = never expires)
  - OHCacher
```
public OHCacher(long maxCapacity,
                int defaultTtl,
                int segmentCount,
                int hashTableSize,
                int compressAbove)
```
    Creates Off-heap Cacher.
    
    Parameters:
    
    maxCapacity - capacity for data over the whole cache in MEGABYTES
    
    segmentCount - mumber of segments (must be a power of 2), defaults to number-of-cores * 2
    
    hashTableSize - hash table size (must be a power of 2), defaults to 8192
    
    defaultTtl - expire time of entries in memory, in seconds (default: 0 = never expires)
    
    compressAbove - compress key and/or value above this size (in BYTES)
- Method Detail
  - started
```
public void started(ServiceBroker broker)
             throws java.lang.Exception
```
    Initializes cacher instance.
    
    Specified by:
    
    started in interface MoleculerLifecycle
    
    Overrides:
    
    started in class Cacher
    
    Parameters:
    
    broker - parent ServiceBroker
    
    Throws:
    
    java.lang.Exception
  - stopped
```
public void stopped()
```
    Specified by:
    
    stopped in interface MoleculerLifecycle
    
    Overrides:
    
    stopped in class MoleculerComponent
  - get
```
public io.datatree.Promise get(java.lang.String key)
```
    Description copied from class: Cacher
    
    Gets a cached content by a key.
    
    Specified by:
    
    get in class Cacher
    
    Parameters:
    
    key - cache key
    
    Returns:
    
    Promise with cached value (or null, the returned Promise also can be null)
  - set
```
public io.datatree.Promise set(java.lang.String key,
                               io.datatree.Tree value,
                               int ttl)
```
    Description copied from class: Cacher
    
    Sets a content by key into the cache.
    
    Specified by:
    
    set in class Cacher
    
    Parameters:
    
    key - cache key
    
    value - new value
    
    ttl - optional TTL of entry (0 == use default TTL)
    
    Returns:
    
    Promise with empty value
  - del
```
public io.datatree.Promise del(java.lang.String key)
```
    Description copied from class: Cacher
    
    Deletes a content from this cache.
    
    Specified by:
    
    del in class Cacher
    
    Parameters:
    
    key - cache key
    
    Returns:
    
    Promise with empty value
  - clean
```
public io.datatree.Promise clean(java.lang.String match)
```
    Description copied from class: Cacher
    
    Cleans this cache. Removes every key by a match string. The default match string is "**".
    
    Specified by:
    
    clean in class Cacher
    
    Parameters:
    
    match - regex
    
    Returns:
    
    Promise with empty value
  - getCacheKeys
```
public io.datatree.Promise getCacheKeys()
```
    Lists all keys of cached entries.
    
    Specified by:
    
    getCacheKeys in class Cacher
    
    Returns:
    
    a Tree object with a "keys" array.
  - keyToBytes
```
protected byte[] keyToBytes(java.lang.String key)
                     throws java.lang.Exception
```
    Throws:
    
    java.lang.Exception
  - bytesToKey
```
protected java.lang.String bytesToKey(byte[] bytes)
                               throws java.lang.Exception
```
    Throws:
    
    java.lang.Exception
  - valueToBytes
```
protected byte[] valueToBytes(io.datatree.Tree tree)
                       throws java.lang.Exception
```
    Throws:
    
    java.lang.Exception
  - bytesToValue
```
protected io.datatree.Tree bytesToValue(byte[] bytes)
                                 throws java.lang.Exception
```
    Throws:
    
    java.lang.Exception
  - getCapacity
```
public long getCapacity()
```
  - setCapacity
```
public void setCapacity(long capacity)
```
  - getSegmentCount
```
public int getSegmentCount()
```
  - setSegmentCount
```
public void setSegmentCount(int segmentCount)
```
  - getHashTableSize
```
public int getHashTableSize()
```
  - setHashTableSize
```
public void setHashTableSize(int hashTableSize)
```
  - getTtl
```
public int getTtl()
```
  - setTtl
```
public void setTtl(int ttl)
```
  - getCompressAbove
```
public int getCompressAbove()
```
  - setCompressAbove
```
public void setCompressAbove(int compressAbove)
```
  - getSerializer
```
public Serializer getSerializer()
```
  - setSerializer
```
public void setSerializer(Serializer serializer)
```
  - getCompressionLevel
```
public int getCompressionLevel()
```
  - setCompressionLevel
```
public void setCompressionLevel(int compressionLevel)
```

Class OHCacher

Nested Class Summary

Field Summary

Fields inherited from class services.moleculer.cacher.Cacher

Fields inherited from class services.moleculer.service.MoleculerComponent

Fields inherited from interface services.moleculer.metrics.MetricConstants

Constructor Summary

Method Summary

Methods inherited from class services.moleculer.cacher.Cacher

Methods inherited from class services.moleculer.service.MoleculerComponent

Methods inherited from class java.lang.Object

Field Detail

CONTENT

capacity

segmentCount

hashTableSize

ttl

compressAbove

compressionLevel

serializer

cache

timer

gaugeExpired

counterGet

counterSet

counterDel

counterClean

counterFound

Constructor Detail

OHCacher

OHCacher

OHCacher

Method Detail

started

stopped

get

set

del

clean

getCacheKeys

keyToBytes

bytesToKey

valueToBytes

bytesToValue

getCapacity

setCapacity

getSegmentCount

setSegmentCount

getHashTableSize

setHashTableSize

getTtl

setTtl

getCompressAbove

setCompressAbove

getSerializer

setSerializer

getCompressionLevel

setCompressionLevel