Class TimeBucketCounterBase

java.lang.Object
org.apache.catalina.util.TimeBucketCounterBase
Direct Known Subclasses:
TimeBucketCounter
public abstract class TimeBucketCounterBase extends Object
This class maintains a thread safe hash map that has timestamp-based buckets followed by a string for a key, and a counter for an integer value. Each time the increment() method is called it adds the key if it does not exist, increments its value and returns it.

  • Constructor Summary

    Constructors
    Constructor
    Description
    TimeBucketCounterBase(int bucketDuration, ScheduledExecutorService executorService)
    Creates a new TimeBucketCounter with the specified lifetime.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    destroy()
    Stops threads created by this object and cleans up resources.
    protected final String
    genKey(String identifier)
    Generates the key of timeBucket counter maps with the specific identifier, and the timestamp is implicitly equivalent to "now".
    protected final String
    genKey(String identifier, long timestamp)
    Generates the key of timeBucket counter maps with the specific identifier and timestamp.
    int
    getBucketDuration()
     
    protected abstract long
    getBucketIndex(long timestamp)
    Calculate the bucket index for the specific timestamp.
    int
    getCurrentBucketPrefix()
    Returns current bucket prefix
    abstract long
    getMillisUntilNextBucket()
    When we want to test a full bucket duration we need to sleep until the next bucket starts.
    abstract double
    getRatio()
    Returns the ratio between the configured duration param and the actual duration.
    final int
    increment(String identifier)
    Increments the counter for the passed identifier in the current time bucket and returns the new value.
    void
    periodicEvict()
    Periodic evict, perform removal of obsolete bucket items.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • TimeBucketCounterBase

      public TimeBucketCounterBase(int bucketDuration, ScheduledExecutorService executorService)
      Creates a new TimeBucketCounter with the specified lifetime.
      Parameters:
      bucketDuration - duration in seconds, e.g. for 1 minute pass 60
      executorService - the executor service that will be used to run the maintenance task
      Throws:
      NullPointerException - if executorService is null.

  • Method Details

    • getBucketDuration

      public int getBucketDuration()
      Returns:
      bucketDuration in seconds

    • getRatio

      public abstract double getRatio()
      Returns the ratio between the configured duration param and the actual duration.
      Returns:
      the ratio between the configured duration param and the actual duration.

    • increment

      public final int increment(String identifier)
      Increments the counter for the passed identifier in the current time bucket and returns the new value.
      Parameters:
      identifier - an identifier for which we want to maintain count, e.g. IP Address
      Returns:
      the count within the current time bucket

    • genKey

      protected final String genKey(String identifier)
      Generates the key of timeBucket counter maps with the specific identifier, and the timestamp is implicitly equivalent to "now".
      Parameters:
      identifier - an identifier for which we want to maintain count
      Returns:
      key of timeBucket counter maps

    • genKey

      protected final String genKey(String identifier, long timestamp)
      Generates the key of timeBucket counter maps with the specific identifier and timestamp.
      Parameters:
      identifier - of target request
      timestamp - when target request received
      Returns:
      key of timeBucket counter maps

    • getBucketIndex

      protected abstract long getBucketIndex(long timestamp)
      Calculate the bucket index for the specific timestamp.
      Parameters:
      timestamp - the specific timestamp in milliseconds
      Returns:
      prefix the bucket key prefix for the specific timestamp

    • getCurrentBucketPrefix

      public int getCurrentBucketPrefix()
      Returns current bucket prefix
      Returns:
      bucket index

    • getMillisUntilNextBucket

      public abstract long getMillisUntilNextBucket()
      When we want to test a full bucket duration we need to sleep until the next bucket starts.

      WARNING: This method is used for test purpose.

      Returns:
      the number of milliseconds until the next bucket

    • destroy

      public void destroy()
      Stops threads created by this object and cleans up resources.

    • periodicEvict

      public void periodicEvict()
      Periodic evict, perform removal of obsolete bucket items. Absence of this operation may result in OOM after a long run.