public UserGroupPendingChanges withUserIdsToAdd(String... userIdsToAdd) {
        if (this.userIdsToAdd == null) {
            setUserIdsToAdd(new com.amazonaws.internal.SdkInternalList<String>(userIdsToAdd.length));
        }
        for (String ele : userIdsToAdd) {
            this.userIdsToAdd.add(ele);
        }
        return this;
    }
<p>
The list of user IDs to add.
</p>
<p>
<b>NOTE:</b> This method appends the values to the existing list (if any). Use
{@link #setUserIdsToAdd(java.util.Collection)} or {@link #withUserIdsToAdd(java.util.Collection)} if you want to
override the existing values.
</p>

@param userIdsToAdd
       The list of user IDs to add.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-elasticache/src/main/java/com/amazonaws/services/elasticache/model/UserGroupPendingChanges.java