code: public CloudhopperBuilder port(String... port) {
  		for (String p : port) {
  			if (port != null) {
  				ports.add(p);
  			}
  		}
  		return this;
  	}
docs: Set the SMPP server port.
  
  You can specify a direct value. For example:
  
  <pre>
  .port("2775");
  </pre>
  
  <p>
  You can also specify one or several property keys. For example:
  
  <pre>
  .port("${custom.property.high-priority}", "${custom.property.low-priority}");
  </pre>
  
  The properties are not immediately evaluated. The evaluation will be done
  when the {@link #build()} method is called.
  
  If you provide several property keys, evaluation will be done on the
  first key and if the property exists (see {@link EnvironmentBuilder}),
  its value is used. If the first property doesn't exist in properties,
  then it tries with the second one and so on.
  
  @param port
  one value, or one or several property keys
  @return this instance for fluent chaining