RateLimiter (Apache HBase 1.2.12 API)

java.lang.Object
- org.apache.hadoop.hbase.quotas.RateLimiter

Direct Known Subclasses:

AverageIntervalRateLimiter, FixedIntervalRateLimiter
```
@InterfaceAudience.Private
@InterfaceStability.Evolving
public abstract class RateLimiter
extends Object
```
Simple rate limiter. Usage Example: // At this point you have a unlimited resource limiter RateLimiter limiter = new AverageIntervalRateLimiter(); or new FixedIntervalRateLimiter(); limiter.set(10, TimeUnit.SECONDS); // set 10 resources/sec while (true) { // call canExecute before performing resource consuming operation bool canExecute = limiter.canExecute(); // If there are no available resources, wait until one is available if (!canExecute) Thread.sleep(limiter.waitInterval()); // ...execute the work and consume the resource... limiter.consume(); }

Field Summary

Fields
Modifier and Type Field and Description

private long avail

private long limit

static String QUOTA_RATE_LIMITER_CONF_KEY

private long tunit

Fields
Modifier and Type	Field and Description
`private long`	`avail`
`private long`	`limit`
`static String`	`QUOTA_RATE_LIMITER_CONF_KEY`
`private long`	`tunit`

Constructor Summary

Constructors
Constructor and Description

RateLimiter()

Constructors
Constructor and Description
`RateLimiter()`

Method Summary

Methods
Modifier and Type	Method and Description
`boolean`	`canExecute()` Is there at least one resource available to allow execution?
`boolean`	`canExecute(long amount)` Are there enough available resources to allow execution?
`void`	`consume()` consume one available unit.
`void`	`consume(long amount)` consume amount available units, amount could be a negative number
`long`	`getAvailable()`
`long`	`getLimit()`
`abstract long`	`getNextRefillTime()`
`protected long`	`getTimeUnitInMillis()`
`(package private) abstract long`	`getWaitInterval(long limit, long available, long amount)` Time in milliseconds to wait for before requesting to consume 'amount' resource.
`boolean`	`isBypass()`
`(package private) abstract long`	`refill(long limit)` Refill the available units w.r.t the elapsed time.
`void`	`set(long limit, TimeUnit timeUnit)` Set the RateLimiter max available resources and refill period.
`abstract void`	`setNextRefillTime(long nextRefillTime)`
`String`	`toString()`
`void`	`update(RateLimiter other)` Sets the current instance of RateLimiter to a new values.
`long`	`waitInterval()`
`long`	`waitInterval(long amount)`

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

- Field Detail
  - QUOTA_RATE_LIMITER_CONF_KEY
```
public static final String QUOTA_RATE_LIMITER_CONF_KEY
```
    See Also:
    Constant Field Values
  - tunit
```
private long tunit
```
  - limit
```
private long limit
```
  - avail
```
private long avail
```
- Constructor Detail
  - RateLimiter
```
public RateLimiter()
```
- Method Detail
  - refill
```
abstract long refill(long limit)
```
    Refill the available units w.r.t the elapsed time.
    
    Parameters:
    limit - Maximum available resource units that can be refilled to.
    
    Returns:
    how many resource units may be refilled ?
  - getWaitInterval
```
abstract long getWaitInterval(long limit,
                   long available,
                   long amount)
```
    Time in milliseconds to wait for before requesting to consume 'amount' resource.
    
    Parameters:
    limit - Maximum available resource units that can be refilled to.
    available - Currently available resource units
    amount - Resources for which time interval to calculate for
    
    Returns:
    estimate of the ms required to wait before being able to provide 'amount' resources.
  - set
```
public void set(long limit,
       TimeUnit timeUnit)
```
    Set the RateLimiter max available resources and refill period.
    
    Parameters:
    limit - The max value available resource units can be refilled to.
    timeUnit - Timeunit factor for translating to ms.
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - update
```
public void update(RateLimiter other)
```
    Sets the current instance of RateLimiter to a new values. if current limit is smaller than the new limit, bump up the available resources. Otherwise allow clients to use up the previously available resources.
  - isBypass
```
public boolean isBypass()
```
  - getLimit
```
public long getLimit()
```
  - getAvailable
```
public long getAvailable()
```
  - getTimeUnitInMillis
```
protected long getTimeUnitInMillis()
```
  - canExecute
```
public boolean canExecute()
```
    Is there at least one resource available to allow execution?
    
    Returns:
    true if there is at least one resource available, otherwise false
  - canExecute
```
public boolean canExecute(long amount)
```
    Are there enough available resources to allow execution?
    
    Parameters:
    amount - the number of required resources, a non-negative number
    
    Returns:
    true if there are enough available resources, otherwise false
  - consume
```
public void consume()
```
    consume one available unit.
  - consume
```
public void consume(long amount)
```
    consume amount available units, amount could be a negative number
    
    Parameters:
    amount - the number of units to consume
  - waitInterval
```
public long waitInterval()
```
    Returns:
    estimate of the ms required to wait before being able to provide 1 resource.
  - waitInterval
```
public long waitInterval(long amount)
```
    Returns:
    estimate of the ms required to wait before being able to provide "amount" resources.
  - setNextRefillTime
```
public abstract void setNextRefillTime(long nextRefillTime)
```
  - getNextRefillTime
```
public abstract long getNextRefillTime()
```

Class RateLimiter

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

QUOTA_RATE_LIMITER_CONF_KEY

tunit

limit

avail

Constructor Detail

RateLimiter

Method Detail

refill

getWaitInterval

set

toString

update

isBypass

getLimit

getAvailable

getTimeUnitInMillis

canExecute

canExecute

consume

consume

waitInterval

waitInterval

setNextRefillTime

getNextRefillTime