@java.lang.Override
  public com.google.protobuf.Duration getDefaultTtl() {
    return defaultTtl_ == null ? com.google.protobuf.Duration.getDefaultInstance() : defaultTtl_;
  }
<pre>
Optional. The default TTL value for all assets under the corpus without a
asset level user-defined TTL. For STREAM_VIDEO type corpora, this is
required and the maximum allowed
  default_ttl is 10 years.
</pre>

<code>.google.protobuf.Duration default_ttl = 5 [(.google.api.field_behavior) = OPTIONAL];
</code>

@return The defaultTtl.
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/Corpus.java