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javabitmaskenumset

convert a two Byte bit mask into a EnumSet

I am reading a binary file that has values stored in bit masks, both 1 Byte bit masks and 2 Byte bit masks. Each bit in the masks act as a switch that indicates where an Event has transpired.

Example of 1 Byte mask: 

00000101

Indicates that Event one and Event 3 has transpired.

Example of Enum

public enum MyEnum 
{
    EventOne,
    EventTwo,
        ....;   
}

I have created a Enum MyEnum(as per Item 32 in Effective java, Second Edition) of the events. How can the binary bit masks be read into an EnumSet<MyEnum>?

Solution 
  • List<MyEnum> list = new ArrayList<MyEnum>();
for (MyEnum value : MyEnum.values()) {
  if ((mask & (1 << value.ordinal())) != 0) {
    list.add(value);
  } 
}
return EnumSet.copyOf(list);

    For the 2 byte mask, combine the 2 bytes into one int. eg:

    int mask = (((int)hbyte) & 0xff) << 8 | (((int)lbyte) & 0xff);