Java : Serial port enumeration and the for-loop

The following code works however I did not write it. It looks through a computers port names and attempts to match one with a specified string (For RxTx serial communcation).

My question is what that the statement inside the for lo开发者_运维知识库op does? I have never seen any arrangement other then for (initialize;condition test;iterator) statement;

Essentially I'm asking what the (String portName : PORT_NAMES) part does and the the ":" operator does?

    private static final String PORT_NAMES[] = {
        "/dev/tty.usbserial-A9007UX1", // Mac OS X
        "/dev/ttyUSB0", // Linux
        "COM4", // Windows
        };

        CommPortIdentifier portId = null;
    Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();

    // iterate through, looking for the port
    while (portEnum.hasMoreElements()) {
        CommPortIdentifier currPortId = (CommPortIdentifier) portEnum.nextElement();
        for (String portName : PORT_NAMES) {
            if (currPortId.getName().equals(portName)) {
                portId = currPortId;
                break;
            }
        }
    }

Thanks

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This is the Java for-each statement. It justs iterates through every element of the collection specified after the : sign.

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It's what I remember having heard called the "extended for" loop. It's basically the Java equivalent of the C# "foreach" operator; it iterates through the String objects in the PORT_NAMES Enumeration.

EDIT: Linky http://leepoint.net/notes-java/flow/loops/foreach.html

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This is the Java for-each construct, which has been familiar since JDK 1.5. It is basically equivalent to this:

for (int i = 0; i < PORT_NAMES.length; ++i) {
    String portName = PORT_NAMES[i];
    etc...
}

So this is a nicer way to iterate over an array or a collection than having to use an index variable which is not used anywhere else in the loop. For more information see the Oracle documentation:

http://download.oracle.com/javase/1,5.0/docs/guide/language/foreach.html