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Refactoring this Java code if String contains any of these capabilities?

I need to check if a string does not contain any of the following lines:

MNC BRA LEB MAR RVK WAY GLZ WWW HYB

My current code:

 if(selectedLocation.equals("OTH"))
 {
    if(!currentClassLocation.equals("MNC") &&
                        !currentClassLocation.equals("BRA") &&
                        !currentClassLocation.equals("LEB") &&
                        !currentClassLocation.equals("MAR") &&
                        !currentClassLocation.equals("RVC") &&
                        !currentClassLocation.equals("WAY") &&
                        !currentClassLocation.equals("GLZ") &&
                        !currentClassLocation.equals("WWW") &&
                        !currentClassLocation.equals("HYB"))
                    {
                         //Awesome, I need this string! I operate on it here.
                    }
 }

In short, I cannot use a for-loop. Is there a way to check if a string contains none of these without iterating?

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8 answers


Use HashSet

:



Set<String> invalidSequences = new HashSet<String>();
invalidSequences.add("MNC");
invalidSequences.add("BRA");
invalidSequences.add("LEB");
// Remaining sequences ...

if (!invalidSequences.contains(currentClassLocation)) {
    // Awesome, I need this string...
}
+9


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Try adding these lines to Set, then find with contains which will be O (c):



public class Filter {
   Set<String> exclusionSet = new HashSet<String>();

   public Filter( String... excludes ) {
       for( String exclusion : excludes ) {
          exclusionSet.add( exclusion );
       }
   }

   public boolean exclude( String src ) {
     return exclusionSet.contains( src );
  }


   public static void main( String[] args ) {
       Filter filter = new Filter( "MNC BRA LEB MAR RVC WAY GLZ WWW HYB".split(" ") );

       for( String arg : args ) {
           System.out.println( arg + " is excluded? " + filter.exclude( arg ) );
       }
   }
}
+2


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Make a HashSet of your strings and do an O (1) check to see if the current location of the class exists in your stringset.

+1


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Try a variation (using your lines):

Pattern pattern = Pattern.compile("(.*(AIN|BIN|CIN|Blam).*)*");
Matcher matcher = pattern.matcher(string_to_test);

Check out the regex java templates here: Java Regex Tester

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If you want to use for-loop you can just use the variable

String[] data = {"BRA","LEB","MAR","RVC","WAY","GLZ","WWW","HYB"};

if(selectedLocation.equals("OTH"))
{
   boolean chk = false;
   for(int i = 0; i < data.length; i++)
      chk |= currentClassLocation.equals(data[i]);

   if(!chk){
      //Awesome, I need this string! I operate on it here.
   }

}
0


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You can also use this if you don't want to manually add installation details.

import java.util.Arrays;


public class StringFind {
    public static void main(String[] args) {
        String stringtotest = "MNC";
        String dataString = "MNC BRA LEB MAR RVC WAY GLZ WWW HYB";
        String[] dataArray= dataString.split(" ");
        Arrays.sort(dataArray); // You can omit this if data is already sorted.
        if(Arrays.binarySearch(dataArray, stringtotest)<0){
            System.out.println("Does not Exists");
        }else{
            System.out.println("Exists");
        }
    }
}
0


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Use a config file to make the list of invalid sequences customizable. For this, the most unpleasant bit, a series of combinations of magic letters. Moving it into a set doesn't help.

0


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Using string array:

String[] arr = {"MNC", "BRA", "LEB", "MAR", "RVC", "WAY", "GLZ", "WWW", "HYB"};
List list = Arrays.asList(arr);
if (!list.contains(currentClassLocation)) {
   ...
}
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