Class ExponentialBackOffSchedulingStrategy

java.lang.Object

org.apache.hc.client5.http.impl.schedule.ExponentialBackOffSchedulingStrategy

All Implemented Interfaces:

SchedulingStrategy

@Contract(threading=STATELESS)
public class ExponentialBackOffSchedulingStrategy
extends Object
implements SchedulingStrategy

An implementation that backs off exponentially based on the number of consecutive failed attempts. It uses the following defaults:

     no delay in case it was never tried or didn't fail so far
    6 s delay for one failed attempt (= getInitialExpiry())
   60 s delay for two failed attempts
 10 min delay for three failed attempts
100 min delay for four failed attempts
  ~16 h delay for five failed attempts
   24 h delay for six or more failed attempts (= getMaxExpiry())

The following equation is used to calculate the delay for a specific pending operation:

    delay = getInitialExpiry() * Math.pow(getBackOffRate(),
    consecutiveFailedAttempts - 1))

The resulting delay won't exceed getMaxExpiry().

Since:

5.0

Field Summary

Fields

Modifier and Type	Field	Description
private final long	backOffRate
static final long	DEFAULT_BACK_OFF_RATE
static final org.apache.hc.core5.util.TimeValue	DEFAULT_INITIAL_EXPIRY
static final org.apache.hc.core5.util.TimeValue	DEFAULT_MAX_EXPIRY
private final org.apache.hc.core5.util.TimeValue	initialExpiry
private final org.apache.hc.core5.util.TimeValue	maxExpiry

Constructor Summary

Constructors

Constructor	Description
ExponentialBackOffSchedulingStrategy()
ExponentialBackOffSchedulingStrategy(long backOffRate)
ExponentialBackOffSchedulingStrategy(long backOffRate, org.apache.hc.core5.util.TimeValue initialExpiry)
ExponentialBackOffSchedulingStrategy(long backOffRate, org.apache.hc.core5.util.TimeValue initialExpiry, org.apache.hc.core5.util.TimeValue maxExpiry)

Method Summary

Modifier and Type	Method	Description
protected org.apache.hc.core5.util.TimeValue	calculateDelay(int consecutiveFailedAttempts)
long	getBackOffRate()
org.apache.hc.core5.util.TimeValue	getInitialExpiry()
org.apache.hc.core5.util.TimeValue	getMaxExpiry()
org.apache.hc.core5.util.TimeValue	schedule(int attemptNumber)	Schedules execution time for an operation.

Methods inherited from class Object

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

Field Details

DEFAULT_BACK_OFF_RATE

public static final long DEFAULT_BACK_OFF_RATE

See Also:

• Constant Field Values

DEFAULT_INITIAL_EXPIRY

public static final org.apache.hc.core5.util.TimeValue DEFAULT_INITIAL_EXPIRY

DEFAULT_MAX_EXPIRY

public static final org.apache.hc.core5.util.TimeValue DEFAULT_MAX_EXPIRY

backOffRate

private final long backOffRate

initialExpiry

private final org.apache.hc.core5.util.TimeValue initialExpiry

maxExpiry

private final org.apache.hc.core5.util.TimeValue maxExpiry

Constructor Details

ExponentialBackOffSchedulingStrategy

public ExponentialBackOffSchedulingStrategy(long backOffRate,
 org.apache.hc.core5.util.TimeValue initialExpiry,
 org.apache.hc.core5.util.TimeValue maxExpiry)

ExponentialBackOffSchedulingStrategy

public ExponentialBackOffSchedulingStrategy(long backOffRate,
 org.apache.hc.core5.util.TimeValue initialExpiry)

ExponentialBackOffSchedulingStrategy

public ExponentialBackOffSchedulingStrategy(long backOffRate)

ExponentialBackOffSchedulingStrategy

public ExponentialBackOffSchedulingStrategy()

Method Details

schedule

public org.apache.hc.core5.util.TimeValue schedule(int attemptNumber)

Description copied from interface: SchedulingStrategy

Schedules execution time for an operation.

Specified by:

schedule in interface SchedulingStrategy

getBackOffRate

public long getBackOffRate()

getInitialExpiry

public org.apache.hc.core5.util.TimeValue getInitialExpiry()

getMaxExpiry

public org.apache.hc.core5.util.TimeValue getMaxExpiry()

calculateDelay

protected org.apache.hc.core5.util.TimeValue calculateDelay(int consecutiveFailedAttempts)