redisson-utils

A couple of useful classes related to Redisson client for Redis

Classes

RLockable

Useful class to deal with Redisson Locks, it copies Java Optional structure. For example:

This is the smallest way to do something when the lock was acquired. If it is not acquired, it will return something else.

var result = RLockable.of(redissonClient.getLock("myLock"), () -> {
            // do something inside lock
            return "acquired-lock-result";
        } ).orElse("non-acquired-lock-result")

In case you need to do something to get the default value when lock couldn't be acquired, then you can use orElseGet:

var result = RLockable.of(redissonClient.getLock("myLock"), () -> {
            // do something inside lock
            return "acquired-lock-result";
        } ).orElseGet(() -> return "non-acquired-lock-result")

Furthermore, if you need to throw an exception, because you expected to acquired the lock, then you can use orElseThrow:

var result = RLockable.of(redissonClient.getLock("myLock"), () -> {
            // do something inside lock
            return "acquired-lock-result";
        } ).orElseThrow(myException::new)

Note: You can supply a method that will return the excpetion to be thrown.

Optionals of RLockable

If you want to setup a waitTime, useful when you don't want to wait forever to acquire the lock, then:

var result = RLockable.of(redissonClient.getLock("myLock"), () -> {
            // do something inside lock
            return "acquired-lock-result";
        } )
        .withTimeUnit(TimeUnit.SECONDS)
        .withWaitTime(30)
        .orElse("non-acquired-lock-result")

Since Redis let you setup also the leaseTime, you can put it like this:

var result = RLockable.of(redissonClient.getLock("myLock"), () -> {
            // do something inside lock
            return "acquired-lock-result";
        } )
        .withTimeUnit(TimeUnit.SECONDS)
        .withWaitTime(30)
        .withLeaseTime(240)
        .orElse("non-acquired-lock-result")

Note: leaseTime and waitTime shares the same timeUnit.

Also, if you want to supply your own exception when interrupted while waiting the lock, you can use withInterruptedExceptionSupplier:

var result = RLockable.of(redissonClient.getLock("myLock"), () -> {
            // do something inside lock
            return "acquired-lock-result";
        } )
        .withTimeUnit(TimeUnit.SECONDS)
        .withWaitTime(30)
        .withInterruptedExceptionSupplier(e -> {
            log.error("Interrupted waiting for lock: myLock");
            return new CustomException(...);
        })        
        .orElse("non-acquired-lock-result")

For more examples, check the tests about the class.

How to install

If you prefer to use maven central releases, you can find it here. Also, if you support Jitpack.io you can find it here