Building Applications with Spring Data Redis - Spring Data - page 106

The source code of this method is given as follows:

private Contact buildContact(Long id) {
String key = buildKey(id);
return buildContact(key);
}

Fourth, we have to implement the method used to verify whether a contact in
question exists or not. Our implementation of the contactDoesNotExist() method
consists of the following steps:

1. Create the key of the contact.

2. Check if the key is found from the contacts set by calling the isMember()

method of the SetOperations class, and passing the name of the set and the
key as parameters.

We use setOperations because we execute only
one command.

3. Inverse the return value of the isMember() method and return the

inverted value.

The source code of this method is given as follows:

private boolean contactDoesNotExist(Long id) {
String key = buildKey(id);
return !redisTemplate.opsForSet().isMember("contacts", key);
}

Fifth, we have to implement the method that saves the information of a single
contact. Our implementation of the persist() method includes the following steps:

1. If the persisted Contact object does not have an ID, create one calling the

incrementAndGet() method of the RedisAtomicLong class and set the
received Long object as the contact ID.

2. Build a key for the persisted contact.

3. Save the contact in the hash.

4. Return the persisted contact.