public String getProjectionExpression() {
        return this.projectionExpression;
    }
<p>
A string that identifies one or more attributes to retrieve from the specified table or index. These attributes
can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by
commas.
</p>
<p>
If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are
not found, they will not appear in the result.
</p>
<p>
For more information, see <a href=
"https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.AccessingItemAttributes.html"
>Specifying Item Attributes</a> in the <i>Amazon DynamoDB Developer Guide</i>.
</p>

@return A string that identifies one or more attributes to retrieve from the specified table or index. These
        attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression
        must be separated by commas.</p>
        <p>
        If no attribute names are specified, then all attributes will be returned. If any of the requested
        attributes are not found, they will not appear in the result.
        </p>
        <p>
        For more information, see <a href=
        "https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.AccessingItemAttributes.html"
        >Specifying Item Attributes</a> in the <i>Amazon DynamoDB Developer Guide</i>.
aws-java-sdk-dynamodb/src/main/java/com/amazonaws/services/dynamodbv2/model/ScanRequest.java