Power of 2 bit operator in Java?

I have a int variable to save the option, that may include none, one or many sub-options like this:

public static final int OPERATOR_PLUS = 1;
public static final int OPERATOR_SUBTRACT = 2;
public static 开发者_Go百科final int OPERATOR_MULTIPLY = 4;
public static final int OPERATOR_DIVIDE = 8;

And I need a function that will return if that variant contains a sub-option. I tried:

return (Operator & Operators);
return (Operator && Operators);

But Eclipse says both of them are grammar errors (both Operator and Operators are int). Please tell me how to use AND Bit operator in Java. In .NET, I use: Operator And Operators.

Thanks.

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Java won't treat an int as a boolean (unlike C++, AFAIU). Try

return (Operator & Operators) > 0;

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What is the return type of your method? If it is boolean, then you should write it like this:

public boolean hasOperatorBit() {
    return (Operator & Operators) != 0;
}

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The first one is the bitwise AND operator, and should be valid syntax, so long as the return type of your method is int, or something equivalent. If you want a boolean return type, you'll need to do something like return (operator & operators) != 0;.

The second one is not valid; it's a logical AND operator, so both of its arguments need to be boolean.

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You need to compare your variable with the operator in question using bitwise AND to see if that is equivalent to the operator.

Eg,

return OPERATOR_PLUS & operators == OPERATOR_PLUS;

Because if you think about how bitwise works, you want to say does my variable contain the bit flag for the operator.

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The first line would be correct to check that, whereas you can only check one operator possibility at a time. Furthermore you have to check whether the result is not equal to 0 to be correct.

return ((operator & sub_operator) != 0);

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public boolean checkOperator(int operators, int operator) {
 return (operators & operator) != 0;
}

Tutorials for better understanding.