Enumeration warning

Question

I want to execute with Eclipse the example code provided from this RxTx web site :

import gnu.io.*;
public class SerialPortLister {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        listPorts();
    }
    private static void listPorts()
    {
        java.util.Enumeration<CommPortIdentifier> portEnum = CommPortIdentifier.getPortIdentifiers();  // this line has the warning
        while ( portEnum.hasMoreElements() ) 
        {
            CommPortIdentifier portIdentifier = portEnum.nextElement();
            System.out.println(portIdentifier.getName()  +  " - " +  getPortTypeName(portIdentifier.getPortType()) );
        }        
    }
    private static String getPortTypeName ( int portType )
    {
        switch ( portType )
        {
            case CommPortIdentifier.PORT_I2C:
                return "I2C";
            case CommPortIdentifier.PORT_PARALLEL:
                return "Parallel";
            case CommPortIdentifier.PORT_RAW:
                return "Raw";
            case CommPortIdentifier.PORT_RS485:
                return "RS485";
            case CommPortIdentifier.PORT_SERIAL:
                return "Serial";
            default:
                return "unknown type";
        }
    }
}

On line 13 there is a warning : Type safety: The expression of type Enumeration needs unchecked conversion to conform to Enumeration<CommPortIdentifier>

What does this warning mean and how to solve it ?

Answer 1

I don't know code of getPortIdentifiers method, but in the current situation:

• The solution is to add the following annotation in front of the method for which the warning is reported: @SuppressWarnings("unchecked")

• You can also cast the type to be unknown type. Example: Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();