public SynthesizeSpeechRequest withEngine(Engine engine) {
        this.engine = engine.toString();
        return this;
    }
<p>
Specifies the engine (<code>standard</code>, <code>neural</code>, <code>long-form</code>, or
<code>generative</code>) for Amazon Polly to use when processing input text for speech synthesis. Provide an
engine that is supported by the voice you select. If you don't provide an engine, the standard engine is selected
by default. If a chosen voice isn't supported by the standard engine, this will result in an error. For
information on Amazon Polly voices and which voices are available for each engine, see <a
href="https://docs.aws.amazon.com/polly/latest/dg/voicelist.html">Available Voices</a>.
</p>
<p>
Type: String
</p>
<p>
Valid Values: <code>standard</code> | <code>neural</code> | <code>long-form</code> | <code>generative</code>
</p>
<p>
Required: Yes
</p>

@param engine
       Specifies the engine (<code>standard</code>, <code>neural</code>, <code>long-form</code>, or
       <code>generative</code>) for Amazon Polly to use when processing input text for speech synthesis. Provide
       an engine that is supported by the voice you select. If you don't provide an engine, the standard engine
       is selected by default. If a chosen voice isn't supported by the standard engine, this will result in an
       error. For information on Amazon Polly voices and which voices are available for each engine, see <a
       href="https://docs.aws.amazon.com/polly/latest/dg/voicelist.html">Available Voices</a>.</p>
       <p>
       Type: String
       </p>
       <p>
       Valid Values: <code>standard</code> | <code>neural</code> | <code>long-form</code> |
       <code>generative</code>
       </p>
       <p>
       Required: Yes
@return Returns a reference to this object so that method calls can be chained together.
@see Engine
aws-java-sdk-polly/src/main/java/com/amazonaws/services/polly/model/SynthesizeSpeechRequest.java