Package org.springframework.util

Class ConcurrencyThrottleSupport

java.lang.Object
org.springframework.util.ConcurrencyThrottleSupport
All Implemented Interfaces:
Serializable
Direct Known Subclasses:
ConcurrencyThrottleInterceptor
public abstract class ConcurrencyThrottleSupport extends Object implements Serializable
Support class for throttling concurrent access to a specific resource.

Designed for use as a base class, with the subclass invoking the beforeAccess() and afterAccess() methods at appropriate points of its workflow. Note that afterAccess should usually be called in a finally block!

The default concurrency limit of this support class is -1 ("unbounded concurrency"). Subclasses may override this default; check the javadoc of the concrete class that you're using.

Since:
1.2.5
Author:
Juergen Hoeller
See Also:

  • Field Details

    • UNBOUNDED_CONCURRENCY

      public static final int UNBOUNDED_CONCURRENCY
      Permit any number of concurrent invocations: that is, don't throttle concurrency.
      See Also:

    • NO_CONCURRENCY

      public static final int NO_CONCURRENCY
      Switch concurrency 'off': that is, don't allow any concurrent invocations.
      See Also:

    • logger

      protected transient Log logger
      Transient to optimize serialization.

  • Constructor Details

    • ConcurrencyThrottleSupport

      public ConcurrencyThrottleSupport()

  • Method Details

    • setConcurrencyLimit

      public void setConcurrencyLimit(int concurrencyLimit)
      Set the maximum number of concurrent access attempts allowed. The default of -1 indicates no concurrency limit at all.

      In principle, this limit can be changed at runtime, although it is generally designed as a config time setting.

      NOTE: Do not switch between -1 and any concrete limit at runtime, as this will lead to inconsistent concurrency counts: A limit of -1 effectively turns off concurrency counting completely.

    • getConcurrencyLimit

      public int getConcurrencyLimit()
      Return the maximum number of concurrent access attempts allowed.

    • isThrottleActive

      public boolean isThrottleActive()
      Return whether this throttle is currently active.
      Returns:
      true if the concurrency limit for this instance is active
      See Also:

    • beforeAccess

      protected void beforeAccess()
      To be invoked before the main execution logic of concrete subclasses.

      This implementation applies the concurrency throttle.

      See Also:

    • onLimitReached

      protected void onLimitReached()
      Triggered by beforeAccess() when the concurrency limit has been reached. The default implementation blocks until the concurrency count allows for entering.
      Since:
      6.2.6

    • afterAccess

      protected void afterAccess()
      To be invoked after the main execution logic of concrete subclasses.
      See Also: