public void setInstanceGenerations(java.util.Collection<String> instanceGenerations) {
        if (instanceGenerations == null) {
            this.instanceGenerations = null;
            return;
        }

        this.instanceGenerations = new com.amazonaws.internal.SdkInternalList<String>(instanceGenerations);
    }
<p>
Indicates whether current or previous generation instance types are included. The current generation instance
types are recommended for use. Current generation instance types are typically the latest two to three
generations in each instance family. For more information, see <a
href="https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-types.html">Instance types</a> in the
<i>Amazon EC2 User Guide</i>.
</p>
<p>
For current generation instance types, specify <code>current</code>.
</p>
<p>
For previous generation instance types, specify <code>previous</code>.
</p>
<p>
Default: Current and previous generation instance types
</p>

@param instanceGenerations
       Indicates whether current or previous generation instance types are included. The current generation
       instance types are recommended for use. Current generation instance types are typically the latest two to
       three generations in each instance family. For more information, see <a
       href="https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-types.html">Instance types</a> in the
       <i>Amazon EC2 User Guide</i>.</p>
       <p>
       For current generation instance types, specify <code>current</code>.
       </p>
       <p>
       For previous generation instance types, specify <code>previous</code>.
       </p>
       <p>
       Default: Current and previous generation instance types
@see InstanceGeneration
aws-java-sdk-ec2/src/main/java/com/amazonaws/services/ec2/model/InstanceRequirementsRequest.java