public void setSourceIdentifier(String sourceIdentifier) {
        this.sourceIdentifier = sourceIdentifier;
    }
<p>
The identifier of the event source to be added:
</p>
<ul>
<li>
<p>
If the source type is an instance, a <code>DBInstanceIdentifier</code> must be provided.
</p>
</li>
<li>
<p>
If the source type is a security group, a <code>DBSecurityGroupName</code> must be provided.
</p>
</li>
<li>
<p>
If the source type is a parameter group, a <code>DBParameterGroupName</code> must be provided.
</p>
</li>
<li>
<p>
If the source type is a snapshot, a <code>DBSnapshotIdentifier</code> must be provided.
</p>
</li>
</ul>

@param sourceIdentifier
       The identifier of the event source to be added:</p>
       <ul>
       <li>
       <p>
       If the source type is an instance, a <code>DBInstanceIdentifier</code> must be provided.
       </p>
       </li>
       <li>
       <p>
       If the source type is a security group, a <code>DBSecurityGroupName</code> must be provided.
       </p>
       </li>
       <li>
       <p>
       If the source type is a parameter group, a <code>DBParameterGroupName</code> must be provided.
       </p>
       </li>
       <li>
       <p>
       If the source type is a snapshot, a <code>DBSnapshotIdentifier</code> must be provided.
       </p>
       </li>
aws-java-sdk-docdb/src/main/java/com/amazonaws/services/docdb/model/AddSourceIdentifierToSubscriptionRequest.java