Map with various time to live of keys

Description

It is cache (map) with various ttl of keys based on Redis expire algorithm and ConcurrentHashMap.

The implementation contains two maps:

1. keys and values,
2. keys and ttl.

And has two variants of cleaning:

1. passive via get(K),
2. active via BackgroundCleaner.

The BackgroundCleaner contains thread pool which is responsible for cleaning map.

Install

Maven

<dependency>
  <groupId>com.github.mchernyakov</groupId>
  <artifactId>various-ttl-map</artifactId>
  <version>0.0.3</version>
</dependency>

Gradle

compile group: 'com.github.mchernyakov', name: 'various-ttl-map', version: '0.0.3'

Usage

Properties

Builder properties:

defaultTtl - default ttl (seconds),

cleaningPoolSize - cleaning pool size (default = 1),

numCleaningAttemptsPerSession - how many attempts cleaner can do in single session,

waterMarkPercent - percent when the cleaner has to start another session (basically it means that we have a lot of expired keys, see algo),

delayMillis- interval between cleaning sessions (millis, default = 1000).

In code

    VariousTtlMap<String, String> map = VariousTtlMapImpl.Builder.newBuilder()
            .setDefaultTtl(2)
            .setCleaningPoolSize(2)
            .setNumCleaningAttemptsPerSession(250)
            .setWaterMarkPercent(10)
            .setDelayMillis(100)
            .build();

    int attempts = 10_000;
    Random random = new Random();
        for (int i = 0; i < attempts; i++) {
        map.put("key_" + random.nextInt(), "val", random.nextInt(5));
    }

Roadmap

• options for primitive map for ttl (several engines),
• async API,
• jmh tests.