title: default constraints for property type
body: <p>In <code>Config.groovy</code> one can specify default constraints that will apply to all properties, e.g. </p>
  
  <pre><code>grails.gorm.default.constraints = {
      '*'(nullable: true)
  }
  </code></pre>
  
  <p>Is there a way to specify default constraints for properties of a certain type? For example, if I want to add a <code>(blank: false)</code> constraint for all <code>String</code> properties is there a way to do that?</p>