IMapK, VPutIfAbsent Method (K, V)Hazelcast .Net Client Class Library
If the specified key is not already associated with a value, associate it with the given value.

Namespace: Hazelcast.Core
Assembly: HazelcastClient3x (in HazelcastClient3x.dll) Version: 3.3.0.9
Syntax

V PutIfAbsent(
	K key,
	V value
)

Parameters

key
Type: K
key
value
Type: V
value

Return Value

Type: V
previous value associated with key or null if there was no mapping for key .
Remarks

If the specified key is not already associated with a value, associate it with the given value. This is equivalent to
if (!map.ContainsKey(key))
    return map.Put(key, value);
else
    return map.Get(key);
except that the action is performed atomically.

Warning:

This method uses GetHashCode and Equals of binary form of the key, not the actual implementations of GetHashCode and Equals defined in key's class.

Warning-2:

This method returns a clone of previous value, not the original (identically equal) value previously put into map.

See Also

Reference