public void setChangeSource(String changeSource) {
        this.changeSource = changeSource;
    }
<p>
The group to which the <code>CausingEntity</code> value belongs. There are five entity groups:
</p>
<ul>
<li>
<p>
<code>ResourceReference</code> entities are <code>Ref</code> intrinsic functions that refer to resources in the
template, such as <code>{ "Ref" : "MyEC2InstanceResource" }</code>.
</p>
</li>
<li>
<p>
<code>ParameterReference</code> entities are <code>Ref</code> intrinsic functions that get template parameter
values, such as <code>{ "Ref" : "MyPasswordParameter" }</code>.
</p>
</li>
<li>
<p>
<code>ResourceAttribute</code> entities are <code>Fn::GetAtt</code> intrinsic functions that get resource
attribute values, such as <code>{ "Fn::GetAtt" : [ "MyEC2InstanceResource", "PublicDnsName" ] }</code>.
</p>
</li>
<li>
<p>
<code>DirectModification</code> entities are changes that are made directly to the template.
</p>
</li>
<li>
<p>
<code>Automatic</code> entities are <code>AWS::CloudFormation::Stack</code> resource types, which are also known
as nested stacks. If you made no changes to the <code>AWS::CloudFormation::Stack</code> resource, CloudFormation
sets the <code>ChangeSource</code> to <code>Automatic</code> because the nested stack's template might have
changed. Changes to a nested stack's template aren't visible to CloudFormation until you run an update on the
parent stack.
</p>
</li>
</ul>

@param changeSource
       The group to which the <code>CausingEntity</code> value belongs. There are five entity groups:</p>
       <ul>
       <li>
       <p>
       <code>ResourceReference</code> entities are <code>Ref</code> intrinsic functions that refer to resources
       in the template, such as <code>{ "Ref" : "MyEC2InstanceResource" }</code>.
       </p>
       </li>
       <li>
       <p>
       <code>ParameterReference</code> entities are <code>Ref</code> intrinsic functions that get template
       parameter values, such as <code>{ "Ref" : "MyPasswordParameter" }</code>.
       </p>
       </li>
       <li>
       <p>
       <code>ResourceAttribute</code> entities are <code>Fn::GetAtt</code> intrinsic functions that get resource
       attribute values, such as <code>{ "Fn::GetAtt" : [ "MyEC2InstanceResource", "PublicDnsName" ] }</code>.
       </p>
       </li>
       <li>
       <p>
       <code>DirectModification</code> entities are changes that are made directly to the template.
       </p>
       </li>
       <li>
       <p>
       <code>Automatic</code> entities are <code>AWS::CloudFormation::Stack</code> resource types, which are also
       known as nested stacks. If you made no changes to the <code>AWS::CloudFormation::Stack</code> resource,
       CloudFormation sets the <code>ChangeSource</code> to <code>Automatic</code> because the nested stack's
       template might have changed. Changes to a nested stack's template aren't visible to CloudFormation until
       you run an update on the parent stack.
       </p>
       </li>
@see ChangeSource
aws-java-sdk-cloudformation/src/main/java/com/amazonaws/services/cloudformation/model/ResourceChangeDetail.java