public void setKey(String key) {
        this.key = key;
    }
<p>
The key (name) of a tag.
</p>
<p>
Valid values: A-Z, a-z, 0-9, space, ".:/=+\-@"
</p>
<p>
Constraints: Each key can be 1-128 characters long.
</p>

@param key
       The key (name) of a tag.</p>
       <p>
       Valid values: A-Z, a-z, 0-9, space, ".:/=+\-@"
       </p>
       <p>
       Constraints: Each key can be 1-128 characters long.
aws-java-sdk-route53/src/main/java/com/amazonaws/services/route53domains/model/Tag.java