org.apache.camel.processor
Class RedeliveryPolicy

java.lang.Object
  org.apache.camel.processor.RedeliveryPolicy

All Implemented Interfaces:

Serializable, Cloneable

public class RedeliveryPolicy
extends Object
implements Cloneable, Serializable

The policy used to decide how many times to redeliver and the time between the redeliveries before being sent to a Dead Letter Channel

The default values are:

• maximumRedeliveries = 0
• redeliverDelay = 1000L (the initial delay)
• maximumRedeliveryDelay = 60 * 1000L
• backOffMultiplier = 2
• useExponentialBackOff = false
• collisionAvoidanceFactor = 0.15d
• useCollisionAvoidance = false
• retriesExhaustedLogLevel = LoggingLevel.DEBUG
• retryAttemptedLogLevel = LoggingLevel.DEBUG
• logStrackTrace = false

Setting the maximumRedeliveries to a negative value such as -1 will then always redeliver (unlimited). Setting the maximumRedeliveries to 0 will disable redelivery.

This policy can be configured either by one of the following two settings:

• using convnetional options, using all the options defined above
• using delay pattern to declare intervals for delays

Note: If using delay patterns then the following options is not used (delay, backOffMultiplier, useExponentialBackOff, useCollisionAvoidance)

Using delay pattern:
The delay pattern syntax is: limit:delay;limit 2:delay 2;limit 3:delay 3;...;limit N:delay N.

How it works is best illustrate with an example with this pattern: delayPattern=5:1000;10:5000:20:20000
The delays will be for attempt in range 0..4 = 0 millis, 5..9 = 1000 millis, 10..19 = 5000 millis, >= 20 = 20000 millis.

If you want to set a starting delay, then use 0 as the first limit, eg: 0:1000;5:5000 will use 1 sec delay until attempt number 5 where it will use 5 seconds going forward.

Version:

$Revision: 791760 $

See Also:

Serialized Form

Field Summary

protected double	backOffMultiplier
protected double	collisionAvoidanceFactor
protected String	delayPattern
protected boolean	logStackTrace
protected int	maximumRedeliveries
protected long	maximumRedeliveryDelay
protected static Random	randomNumberGenerator
protected long	redeliverDelay
protected LoggingLevel	retriesExhaustedLogLevel
protected LoggingLevel	retryAttemptedLogLevel
protected boolean	useCollisionAvoidance
protected boolean	useExponentialBackOff

Constructor Summary

RedeliveryPolicy()

Method Summary

RedeliveryPolicy	backOffMultiplier(double multiplier) Enables exponential backoff and sets the multiplier used to increase the delay between redeliveries
protected static long	calculateRedeliverDelayUsingPattern(String delayPattern, int redeliveryCounter) Calculates the delay using the delay pattern
protected long	calculateRedeliveryDelay(long previousDelay, int redeliveryCounter)
RedeliveryPolicy	collisionAvoidancePercent(double collisionAvoidancePercent) Enables collision avoidance and sets the percentage used
RedeliveryPolicy	copy()
RedeliveryPolicy	delayPattern(String delayPattern) Sets the delay pattern with delay intervals.
RedeliveryPolicy	disableRedelivery() Disables redelivery by setting maximum redeliveries to 0.
double	getBackOffMultiplier()
double	getCollisionAvoidanceFactor()
short	getCollisionAvoidancePercent()
String	getDelayPattern()
int	getMaximumRedeliveries()
long	getMaximumRedeliveryDelay()
protected static Random	getRandomNumberGenerator()
long	getRedeliverDelay()
LoggingLevel	getRetriesExhaustedLogLevel()
LoggingLevel	getRetryAttemptedLogLevel()
boolean	isLogStackTrace()
boolean	isUseCollisionAvoidance()
boolean	isUseExponentialBackOff()
RedeliveryPolicy	logStackTrace(boolean logStackTrace) Sets the logging level to use for log messages when retries are attempted.
RedeliveryPolicy	maximumRedeliveries(int maximumRedeliveries) Sets the maximum number of times a message exchange will be redelivered
RedeliveryPolicy	maximumRedeliveryDelay(long maximumRedeliveryDelay) Sets the maximum redelivery delay if using exponential back off.
RedeliveryPolicy	redeliverDelay(long delay) Sets the delay in milliseconds
RedeliveryPolicy	retriesExhaustedLogLevel(LoggingLevel retriesExhaustedLogLevel) Sets the logging level to use for log messages when retries have been exhausted.
RedeliveryPolicy	retryAttemptedLogLevel(LoggingLevel retryAttemptedLogLevel) Sets the logging level to use for log messages when retries are attempted.
void	setBackOffMultiplier(double backOffMultiplier) Sets the multiplier used to increase the delay between redeliveries if setUseExponentialBackOff(boolean) is enabled
void	setCollisionAvoidanceFactor(double collisionAvoidanceFactor) Sets the factor used for collision avoidance if enabled via setUseCollisionAvoidance(boolean)
void	setCollisionAvoidancePercent(double collisionAvoidancePercent) Sets the percentage used for collision avoidance if enabled via setUseCollisionAvoidance(boolean)
void	setDelayPattern(String delayPattern) Sets an optional delay pattern to use insted of fixed delay.
void	setLogStackTrace(boolean logStackTrace) Sets wheter stack traces should be logged or not
void	setMaximumRedeliveries(int maximumRedeliveries) Sets the maximum number of times a message exchange will be redelivered.
void	setMaximumRedeliveryDelay(long maximumRedeliveryDelay) Sets the maximum redelivery delay if using exponential back off.
void	setRedeliverDelay(long redeliverDelay) Sets the delay in milliseconds
void	setRetriesExhaustedLogLevel(LoggingLevel retriesExhaustedLogLevel) Sets the logging level to use for log messages when retries have been exhausted.
void	setRetryAttemptedLogLevel(LoggingLevel retryAttemptedLogLevel) Sets the logging level to use for log messages when retries are attempted.
void	setUseCollisionAvoidance(boolean useCollisionAvoidance) Enables/disables collision avoidance which adds some randomization to the backoff timings to reduce contention probability
void	setUseExponentialBackOff(boolean useExponentialBackOff) Enables/disables exponential backoff using the getBackOffMultiplier() to increase the time between retries
boolean	shouldRedeliver(Exchange exchange, int redeliveryCounter, Predicate retryUntil) Returns true if the policy decides that the message exchange should be redelivered.
long	sleep(long redeliveryDelay, int redeliveryCounter) Calculates the new redelivery delay based on the last one then sleeps for the necessary amount of time
String	toString()
RedeliveryPolicy	useCollisionAvoidance() Enables collision avoidance which adds some randomization to the backoff timings to reduce contention probability
RedeliveryPolicy	useExponentialBackOff() Enables exponential backoff using the getBackOffMultiplier() to increase the time between retries

Methods inherited from class java.lang.Object

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

Field Detail

randomNumberGenerator

protected static transient Random randomNumberGenerator

redeliverDelay

protected long redeliverDelay

maximumRedeliveries

protected int maximumRedeliveries

maximumRedeliveryDelay

protected long maximumRedeliveryDelay

backOffMultiplier

protected double backOffMultiplier

useExponentialBackOff

protected boolean useExponentialBackOff

collisionAvoidanceFactor

protected double collisionAvoidanceFactor

useCollisionAvoidance

protected boolean useCollisionAvoidance

retriesExhaustedLogLevel

protected LoggingLevel retriesExhaustedLogLevel

retryAttemptedLogLevel

protected LoggingLevel retryAttemptedLogLevel

logStackTrace

protected boolean logStackTrace

delayPattern

protected String delayPattern

Constructor Detail

RedeliveryPolicy

public RedeliveryPolicy()

Method Detail

toString

public String toString()

Overrides:

toString in class Object

copy

public RedeliveryPolicy copy()

shouldRedeliver

public boolean shouldRedeliver(Exchange exchange,
                               int redeliveryCounter,
                               Predicate retryUntil)

Returns true if the policy decides that the message exchange should be redelivered.

Parameters:

exchange - the current exchange

redeliveryCounter - the current retry counter

retryUntil - an optional predicate to determine if we should redeliver or not

Returns:

true to redeliver, false to stop

sleep

public long sleep(long redeliveryDelay,
                  int redeliveryCounter)
           throws InterruptedException

Calculates the new redelivery delay based on the last one then sleeps for the necessary amount of time

Parameters:

redeliveryDelay - previous redelivery delay

redeliveryCounter - number of previous redelivery attempts

Returns:

the calculate delay

Throws:

InterruptedException - is thrown if the sleep is interruped likely because of shutdown

calculateRedeliveryDelay

protected long calculateRedeliveryDelay(long previousDelay,
                                        int redeliveryCounter)

calculateRedeliverDelayUsingPattern

protected static long calculateRedeliverDelayUsingPattern(String delayPattern,
                                                          int redeliveryCounter)

Calculates the delay using the delay pattern

redeliverDelay

public RedeliveryPolicy redeliverDelay(long delay)

Sets the delay in milliseconds

maximumRedeliveries

public RedeliveryPolicy maximumRedeliveries(int maximumRedeliveries)

Sets the maximum number of times a message exchange will be redelivered

useCollisionAvoidance

public RedeliveryPolicy useCollisionAvoidance()

Enables collision avoidance which adds some randomization to the backoff timings to reduce contention probability

useExponentialBackOff

public RedeliveryPolicy useExponentialBackOff()

Enables exponential backoff using the getBackOffMultiplier() to increase the time between retries

backOffMultiplier

public RedeliveryPolicy backOffMultiplier(double multiplier)

Enables exponential backoff and sets the multiplier used to increase the delay between redeliveries

collisionAvoidancePercent

public RedeliveryPolicy collisionAvoidancePercent(double collisionAvoidancePercent)

Enables collision avoidance and sets the percentage used

maximumRedeliveryDelay

public RedeliveryPolicy maximumRedeliveryDelay(long maximumRedeliveryDelay)

Sets the maximum redelivery delay if using exponential back off. Use -1 if you wish to have no maximum

retriesExhaustedLogLevel

public RedeliveryPolicy retriesExhaustedLogLevel(LoggingLevel retriesExhaustedLogLevel)

Sets the logging level to use for log messages when retries have been exhausted.

retryAttemptedLogLevel

public RedeliveryPolicy retryAttemptedLogLevel(LoggingLevel retryAttemptedLogLevel)

Sets the logging level to use for log messages when retries are attempted.

logStackTrace

public RedeliveryPolicy logStackTrace(boolean logStackTrace)

Sets the logging level to use for log messages when retries are attempted.

delayPattern

public RedeliveryPolicy delayPattern(String delayPattern)

Sets the delay pattern with delay intervals.

disableRedelivery

public RedeliveryPolicy disableRedelivery()

Disables redelivery by setting maximum redeliveries to 0.

getRedeliverDelay

public long getRedeliverDelay()

setRedeliverDelay

public void setRedeliverDelay(long redeliverDelay)

Sets the delay in milliseconds

getBackOffMultiplier

public double getBackOffMultiplier()

setBackOffMultiplier

public void setBackOffMultiplier(double backOffMultiplier)

Sets the multiplier used to increase the delay between redeliveries if setUseExponentialBackOff(boolean) is enabled

getCollisionAvoidancePercent

public short getCollisionAvoidancePercent()

setCollisionAvoidancePercent

public void setCollisionAvoidancePercent(double collisionAvoidancePercent)

Sets the percentage used for collision avoidance if enabled via setUseCollisionAvoidance(boolean)

getCollisionAvoidanceFactor

public double getCollisionAvoidanceFactor()

setCollisionAvoidanceFactor

public void setCollisionAvoidanceFactor(double collisionAvoidanceFactor)

Sets the factor used for collision avoidance if enabled via setUseCollisionAvoidance(boolean)

getMaximumRedeliveries

public int getMaximumRedeliveries()

setMaximumRedeliveries

public void setMaximumRedeliveries(int maximumRedeliveries)

Sets the maximum number of times a message exchange will be redelivered. Setting a negative value will retry forever.

getMaximumRedeliveryDelay

public long getMaximumRedeliveryDelay()

setMaximumRedeliveryDelay

public void setMaximumRedeliveryDelay(long maximumRedeliveryDelay)

Sets the maximum redelivery delay if using exponential back off. Use -1 if you wish to have no maximum

isUseCollisionAvoidance

public boolean isUseCollisionAvoidance()

setUseCollisionAvoidance

public void setUseCollisionAvoidance(boolean useCollisionAvoidance)

Enables/disables collision avoidance which adds some randomization to the backoff timings to reduce contention probability

isUseExponentialBackOff

public boolean isUseExponentialBackOff()

setUseExponentialBackOff

public void setUseExponentialBackOff(boolean useExponentialBackOff)

Enables/disables exponential backoff using the getBackOffMultiplier() to increase the time between retries

getRandomNumberGenerator

protected static Random getRandomNumberGenerator()

setRetriesExhaustedLogLevel

public void setRetriesExhaustedLogLevel(LoggingLevel retriesExhaustedLogLevel)

Sets the logging level to use for log messages when retries have been exhausted.

getRetriesExhaustedLogLevel

public LoggingLevel getRetriesExhaustedLogLevel()

setRetryAttemptedLogLevel

public void setRetryAttemptedLogLevel(LoggingLevel retryAttemptedLogLevel)

Sets the logging level to use for log messages when retries are attempted.

getRetryAttemptedLogLevel

public LoggingLevel getRetryAttemptedLogLevel()

getDelayPattern

public String getDelayPattern()

setDelayPattern

public void setDelayPattern(String delayPattern)

Sets an optional delay pattern to use insted of fixed delay.

isLogStackTrace

public boolean isLogStackTrace()

setLogStackTrace

public void setLogStackTrace(boolean logStackTrace)

Sets wheter stack traces should be logged or not