public AddSourceIdentifierToSubscriptionRequest withSourceIdentifier(String sourceIdentifier) {
        setSourceIdentifier(sourceIdentifier);
        return this;
    }
<p>
The identifier of the event source to be added.
</p>
<p>
Constraints:
</p>
<ul>
<li>
<p>
If the source type is a DB instance, then a <code>DBInstanceIdentifier</code> must be supplied.
</p>
</li>
<li>
<p>
If the source type is a DB security group, a <code>DBSecurityGroupName</code> must be supplied.
</p>
</li>
<li>
<p>
If the source type is a DB parameter group, a <code>DBParameterGroupName</code> must be supplied.
</p>
</li>
<li>
<p>
If the source type is a DB snapshot, a <code>DBSnapshotIdentifier</code> must be supplied.
</p>
</li>
</ul>

@param sourceIdentifier
       The identifier of the event source to be added.</p>
       <p>
       Constraints:
       </p>
       <ul>
       <li>
       <p>
       If the source type is a DB instance, then a <code>DBInstanceIdentifier</code> must be supplied.
       </p>
       </li>
       <li>
       <p>
       If the source type is a DB security group, a <code>DBSecurityGroupName</code> must be supplied.
       </p>
       </li>
       <li>
       <p>
       If the source type is a DB parameter group, a <code>DBParameterGroupName</code> must be supplied.
       </p>
       </li>
       <li>
       <p>
       If the source type is a DB snapshot, a <code>DBSnapshotIdentifier</code> must be supplied.
       </p>
       </li>
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-neptune/src/main/java/com/amazonaws/services/neptune/model/AddSourceIdentifierToSubscriptionRequest.java