services.moleculer.cacher

Class MemoryCacher

java.lang.Object

services.moleculer.service.MoleculerComponent

services.moleculer.service.Middleware

services.moleculer.cacher.Cacher

services.moleculer.cacher.MemoryCacher

All Implemented Interfaces:

java.lang.Runnable

public class MemoryCacher
extends Cacher
implements java.lang.Runnable

On-heap memory cache. MemoryCacher is the fastest cache implementation in Moleculer. This can be a "distributed" cache, the content of the other node's cache is removable via events; the developer can send distributed events that erase the cache on the other nodes - but this is not automatic! Supports global and entry-level TTL configuration. Configuration properties:

• capacity: Maximum capacity per partition (must be a power of 2), defaults to 2048
• ttl: Expire time of entries in memory, in seconds (default: 0 = never expires)
• cleanup: Cleanup period, in seconds

Performance (small and large data): 5.5 million gets / second (per thread / core)

See Also:

RedisCacher, OHCacher

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	MemoryCacher.MemoryPartition
protected static class	MemoryCacher.PartitionEntry

Field Summary

Fields

Modifier and Type	Field and Description
protected int	capacity Maximum number of entries per partition
protected int	cleanup Cleanup period time, in SECONDS (0 = disable cleanup process)
protected java.util.HashMap<java.lang.String,MemoryCacher.MemoryPartition>	partitions
protected java.util.concurrent.locks.Lock	readLock
protected java.util.concurrent.ScheduledFuture<?>	timer Cancelable timer
protected int	ttl Expire time, in SECONDS (0 = never expires)
protected java.util.concurrent.locks.Lock	writeLock

Fields inherited from class services.moleculer.service.MoleculerComponent

broker, logger, name

Constructor Summary

Constructors

Constructor and Description
MemoryCacher()
MemoryCacher(int capacityPerPartition, int defaultTtl)
MemoryCacher(int capacityPerPartition, int defaultTtl, int cleanupSeconds)

Method Summary

Modifier and Type	Method and Description
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.
int	getCapacity()
int	getCleanup()
int	getTtl()
protected static int	partitionPosition(java.lang.String key, boolean throwErrorIfMissing)
void	run()
io.datatree.Promise	set(java.lang.String key, io.datatree.Tree value, int ttl) Sets a content by key into the cache.
void	setCapacity(int capacity)
void	setCleanup(int cleanup)
void	setTtl(int ttl)
void	started(ServiceBroker broker) Initializes cacher instance.
void	stopped()

Methods inherited from class services.moleculer.cacher.Cacher

appendToKey, appendTree, getCacheKey, install, 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

capacity

protected int capacity

Maximum number of entries per partition

ttl

protected int ttl

Expire time, in SECONDS (0 = never expires)

cleanup

protected int cleanup

Cleanup period time, in SECONDS (0 = disable cleanup process)

readLock

protected final java.util.concurrent.locks.Lock readLock

writeLock

protected final java.util.concurrent.locks.Lock writeLock

partitions

protected final java.util.HashMap<java.lang.String,MemoryCacher.MemoryPartition> partitions

timer

protected volatile java.util.concurrent.ScheduledFuture<?> timer

Cancelable timer

Constructor Detail

MemoryCacher

public MemoryCacher()

MemoryCacher

public MemoryCacher(int capacityPerPartition,
                    int defaultTtl)

MemoryCacher

public MemoryCacher(int capacityPerPartition,
                    int defaultTtl,
                    int cleanupSeconds)

Method Detail

started

public void started(ServiceBroker broker)
             throws java.lang.Exception

Initializes cacher instance.

Overrides:

started in class MoleculerComponent

Parameters:

broker - parent ServiceBroker

Throws:

java.lang.Exception

run

public void run()

Specified by:

run in interface java.lang.Runnable

stopped

public void stopped()

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

partitionPosition

protected static final int partitionPosition(java.lang.String key,
                                             boolean throwErrorIfMissing)

getCapacity

public int getCapacity()

setCapacity

public void setCapacity(int capacity)

getTtl

public int getTtl()

setTtl

public void setTtl(int ttl)

getCleanup

public int getCleanup()

setCleanup

public void setCleanup(int cleanup)