Clash Royale CLAN TAG#URR8PPP

Store array of settings into database row

I want to optimize into database row application settings. Something like this

10 - enabled option 1;
12 - enabled option 2;
13 - enabled option 3;


And the entire number is stored into database as 1073741823.

I tried to implement this:

public void test()

// Let's say you get a String representing your option from your database
String optionFromDB= "132456";
// optionFromDB is a number like "132456"
// We transform it to bigDecimal:
BigDecimal myOptions=new BigDecimal(optionFromDB);

// Then we can use it.

// enable the option X (X is a number)
myOptions.setBit(2);

// Disable option X
myOptions.clearBit(2);

// Save the options to the db:
String newValToSave=myOptions.toString();

// do something if option x enable:
if (myOptions.testBit(123))
System.out.println("test");




How I can implement this properly?

2 Answers
2

Assume value is an integer - this will give you 32 options. If that's not enough, you can take long (64 bits) or apply the same logic to any number of bits.

Thanks, can you show me some Java example, please?
– Peter Penzov
2 days ago

This is Java example.
– jurez
2 days ago

Can you show me with Java methods and etc.
– Peter Penzov
2 days ago

public int enableBit(int value, int bit) return value . I'm sure you can figure out the rest.
– jurez
2 days ago

public int enableBit(int value, int bit) return value

I'm not sure how to ge the final result -> 1073741823
– Peter Penzov
2 days ago

Well, just use a number, let's call it state. The type should be decided according to the number of options that you will have. For instance if you have 10 options, Integer is more than enough. For each option you can use one bit of this integer state.

Integer

So to set the first option just set first bit, and in general the ith bit for the ith option. To see if the ith option is enabled check if the ith bit of the state is set.

For setting the ith bit you can use the following code:

state |= 1 << i;


For testing the ith bit the following:

state & (1L << i)) != 0;


For clearing the ith bit use:

state &= ~(1 << i);


Can you show me some code example how to implement it?
– Peter Penzov
2 days ago

Yes, in a second.
– NiVeR
2 days ago

Can you please show me complete Java code with methods and etc.
– Peter Penzov
2 days ago

It is, just use it according to needs.
– NiVeR
2 days ago

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