Jun 29, 2022

Mini Convert library in Java

This code helps you convert in an easy way the primitive types in Java

the library contains:

- Convert class with the methods to convert your types

- BaseConverter class with the method convertBase that always returns a string of the number in the base you select*

I descourage using the Base Converter class because I coded it specifically for one small project, and doesn't support decimal and/or negative numbers.

Anyways, the code is this:

primitive types conversion

class Convert{
  private static final char[] validNumbers= {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};

  // String
  public static String string(int integer){
    return Integer.toString(integer);
  }

  public static String string(boolean bool){
    if (bool){
      return "true";
    }
    return "false";
  }

  public static void string(String string){
    throw new Error(string+ " is already a string, can't convert it");
  }

  public static String string(boolean[] boolArr){
    if (boolArr.length== 0){return "{}";}
    String refill= "{";
    for (int i=0; i<boolArr.length; i++){
      refill+= string(boolArr[i])+ ", ";
    }
    refill= General.removeLastChar(General.removeLastChar(refill))+ "}";
    return refill;
  }
  
  public static String string(String[] stringArr){
    if (stringArr.length== 0){return "{}";}
    String refill= "{";
    for (int i=0; i<stringArr.length; i++){
      refill+= "\""+ stringArr[i]+ "\", ";
    }
    refill= General.removeLastChar(General.removeLastChar(refill))+ "}";
    return refill;
  }
  
  public static String string(char[] charArr){
    if (charArr.length== 0){return "{}";}
    String refill= "{";
    for (int i=0; i<charArr.length; i++){
      refill+= "'"+ charArr[i]+ "', ";
    }
    refill= General.removeLastChar(General.removeLastChar(refill))+ "}";
    return refill;
  }
  
  public static String string(int[] intArr){
    if (intArr.length== 0){return "{}";}
    String refill= "{";
    for (int i=0; i<intArr.length; i++){
      refill+= string(intArr[i])+ ", ";
    }
    refill= General.removeLastChar(General.removeLastChar(refill))+ "}";
    return refill;
  }

  // int
  public static int integer(String string){
    try{
      return Integer.parseInt(string);
    }
    catch (NumberFormatException error){
      throw new Error("The string does not represent an integer type\nstring passed in: "+ string);
    }
  }

  public static int integer(char character){
    for (int i=0; i<validNumbers.length; i++){
      if (character== validNumbers[i]){
        return Character.getNumericValue(character);
      }
    }
    throw new Error("The character does not represent an integer type\ncharacter passed in: "+ character);
  }

  public static int integer(boolean bool){
    if (bool== true){
      return 1;
    }
    return 0;
  }

  public static int integer(double number){
    return (int)number;
  }
  
  public static int integer(float number){
    return (int)number;
  }
  
  public static int integer(long number){
    return (int)number;
  }

  // float
  public static float decimal(String string){
    try {
      return Float.parseFloat(string);
    }
    catch (NumberFormatException error){
      throw new Error("invalid string passed for float conversion:\nstring passed: "+ string);
    }
  }
  
  // boolean
  public static boolean bool(int integer){
    return integer!= 0;
  }

  public static boolean bool(String string){
    return string.length()!= 0;
  }

  public static boolean bool(char[] charArray){
    return charArray.length!= 0;
  }

  public static boolean bool(int[] intArray){
    return intArray.length!= 0;
  }

  public static boolean bool(String[] strArray){
    return strArray.length!= 0;
  }

  public static boolean bool(boolean[] boolArray){
    return boolArray.length!= 0;
  }

  // char
  public static char character(int number){
    return charArr(number)[0];
  }

  public static char character(String string){
    return string.charAt(0);
  }

  // char[]
  public static char[] charArr(String string){
    return string.toCharArray();
  }

  public static char[] charArr(int integer){
    String strInteger= string(integer);
    return charArr(strInteger);
  }
}

numeric base conversion

import java.util.Hashtable;

class BaseConverter{
  static final Hashtable<Character, Integer> charToNumber = new Hashtable<Character, Integer>(){{
    put('0', 0);
    put('1', 1);
    put('2', 2);
    put('3', 3);
    put('4', 4);
    put('5', 5);
    put('6', 6);
    put('7', 7);
    put('8', 8);
    put('9', 9);
    put('a', 10);
    put('b', 11);
    put('c', 12);
    put('d', 13);
    put('e', 14);
    put('f', 15);
    put('g', 16);
    put('h', 17);
    put('i', 18);
    put('j', 19);
    put('k', 20);
    put('l', 21);
    put('m', 22);
    put('n', 23);
    put('o', 24);
    put('p', 25);
    put('q', 26);
    put('r', 27);
    put('s', 28);
    put('t', 29);
    put('u', 30);
    put('v', 31);
    put('w', 32);
    put('x', 33);
    put('y', 34);
    put('z', 35);
  }};
  
  static final Hashtable<Integer, Character> numberToChar = new Hashtable<Integer, Character>(){{
    put(0, '0');
    put(1, '1');
    put(2, '2');
    put(3, '3');
    put(4, '4');
    put(5, '5');
    put(6, '6');
    put(7, '7');
    put(8, '8');
    put(9, '9');
    put(10, 'a');
    put(11, 'b');
    put(12, 'c');
    put(13, 'd');
    put(14, 'e');
    put(15, 'f');
    put(16, 'g');
    put(17, 'h');
    put(18, 'i');
    put(19, 'j');
    put(20, 'k');
    put(21, 'l');
    put(22, 'm');
    put(23, 'n');
    put(24, 'o');
    put(25, 'p');
    put(26, 'q');
    put(27, 'r');
    put(28, 's');
    put(29, 't');
    put(30, 'u');
    put(31, 'v');
    put(32, 'w');
    put(33, 'x');
    put(34, 'y');
    put(35, 'z');
  }};
  
  public static String convertBase(String strNumber, int targetBase){
    return convertBase(strNumber, 10, targetBase);
  }
  public static String convertBase(int number, int targetBase){
    return convertBase(Convert.string(number), 10, targetBase);
  }
  public static String convertBase(int number, int currentBase, int targetBase){
    return convertBase(Convert.string(number), currentBase, targetBase);
  }
  public static String convertBase(String strNumber, int currentBase, int targetBase){
    if (currentBase<2 || targetBase<2){
      throw new Error("a numeric base can not be less than 2:\nbases passed in:"+ currentBase+ ", "+ targetBase);
    }
    if (currentBase== targetBase)   {return strNumber;}
    if (strNumber.equals("0"))      {return "0";}

    char[] charArrNumber= Convert.charArr(strNumber);

    if (currentBase== 10){
      int number= Convert.integer(strNumber);
      String refill= "";
      
      while (number> 0){
        refill= General.prepend(numberToChar.get(number% targetBase), refill);
        number/= targetBase;
      }
      
      return refill;
    }

    else{
      // conversion to base 10
      int refill= 0;
      for (int i=0; i<charArrNumber.length; i++){
        refill+= charToNumber.get(Character.toLowerCase(charArrNumber[charArrNumber.length-1-i]))* Math.pow(currentBase, i);
      }
  
      // conversion to the correct base with "recursion"
      return convertBase(Convert.string(refill), targetBase); 
    }
  }
}

the complete "library" is this:

import java.util.Hashtable;

class Convert{
  private static final char[] validNumbers= {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};

  // String
  public static String string(int integer){
    return Integer.toString(integer);
  }

  public static String string(boolean bool){
    if (bool){
      return "true";
    }
    return "false";
  }

  public static void string(String string){
    throw new Error(string+ " is already a string, can't convert it");
  }

  public static String string(boolean[] boolArr){
    if (boolArr.length== 0){return "{}";}
    String refill= "{";
    for (int i=0; i<boolArr.length; i++){
      refill+= string(boolArr[i])+ ", ";
    }
    refill= General.removeLastChar(General.removeLastChar(refill))+ "}";
    return refill;
  }
  
  public static String string(String[] stringArr){
    if (stringArr.length== 0){return "{}";}
    String refill= "{";
    for (int i=0; i<stringArr.length; i++){
      refill+= "\""+ stringArr[i]+ "\", ";
    }
    refill= General.removeLastChar(General.removeLastChar(refill))+ "}";
    return refill;
  }
  
  public static String string(char[] charArr){
    if (charArr.length== 0){return "{}";}
    String refill= "{";
    for (int i=0; i<charArr.length; i++){
      refill+= "'"+ charArr[i]+ "', ";
    }
    refill= General.removeLastChar(General.removeLastChar(refill))+ "}";
    return refill;
  }
  
  public static String string(int[] intArr){
    if (intArr.length== 0){return "{}";}
    String refill= "{";
    for (int i=0; i<intArr.length; i++){
      refill+= string(intArr[i])+ ", ";
    }
    refill= General.removeLastChar(General.removeLastChar(refill))+ "}";
    return refill;
  }

  // int
  public static int integer(String string){
    try{
      return Integer.parseInt(string);
    }
    catch (NumberFormatException error){
      throw new Error("The string does not represent an integer type\nstring passed in: "+ string);
    }
  }

  public static int integer(char character){
    for (int i=0; i<validNumbers.length; i++){
      if (character== validNumbers[i]){
        return Character.getNumericValue(character);
      }
    }
    throw new Error("The character does not represent an integer type\ncharacter passed in: "+ character);
  }

  public static int integer(boolean bool){
    if (bool== true){
      return 1;
    }
    return 0;
  }

  public static int integer(double number){
    return (int)number;
  }
  
  public static int integer(float number){
    return (int)number;
  }
  
  public static int integer(long number){
    return (int)number;
  }

  // float
  public static float decimal(String string){
    try {
      return Float.parseFloat(string);
    }
    catch (NumberFormatException error){
      throw new Error("invalid string passed for float conversion:\nstring passed: "+ string);
    }
  }
  
  // boolean
  public static boolean bool(int integer){
    return integer!= 0;
  }

  public static boolean bool(String string){
    return string.length()!= 0;
  }

  public static boolean bool(char[] charArray){
    return charArray.length!= 0;
  }

  public static boolean bool(int[] intArray){
    return intArray.length!= 0;
  }

  public static boolean bool(String[] strArray){
    return strArray.length!= 0;
  }

  public static boolean bool(boolean[] boolArray){
    return boolArray.length!= 0;
  }

  // char
  public static char character(int number){
    return charArr(number)[0];
  }

  public static char character(String string){
    return string.charAt(0);
  }

  // char[]
  public static char[] charArr(String string){
    return string.toCharArray();
  }

  public static char[] charArr(int integer){
    String strInteger= string(integer);
    return charArr(strInteger);
  }
}

class BaseConverter{
  static final Hashtable<Character, Integer> charToNumber = new Hashtable<Character, Integer>(){{
    put('0', 0);
    put('1', 1);
    put('2', 2);
    put('3', 3);
    put('4', 4);
    put('5', 5);
    put('6', 6);
    put('7', 7);
    put('8', 8);
    put('9', 9);
    put('a', 10);
    put('b', 11);
    put('c', 12);
    put('d', 13);
    put('e', 14);
    put('f', 15);
    put('g', 16);
    put('h', 17);
    put('i', 18);
    put('j', 19);
    put('k', 20);
    put('l', 21);
    put('m', 22);
    put('n', 23);
    put('o', 24);
    put('p', 25);
    put('q', 26);
    put('r', 27);
    put('s', 28);
    put('t', 29);
    put('u', 30);
    put('v', 31);
    put('w', 32);
    put('x', 33);
    put('y', 34);
    put('z', 35);
  }};
  
  static final Hashtable<Integer, Character> numberToChar = new Hashtable<Integer, Character>(){{
    put(0, '0');
    put(1, '1');
    put(2, '2');
    put(3, '3');
    put(4, '4');
    put(5, '5');
    put(6, '6');
    put(7, '7');
    put(8, '8');
    put(9, '9');
    put(10, 'a');
    put(11, 'b');
    put(12, 'c');
    put(13, 'd');
    put(14, 'e');
    put(15, 'f');
    put(16, 'g');
    put(17, 'h');
    put(18, 'i');
    put(19, 'j');
    put(20, 'k');
    put(21, 'l');
    put(22, 'm');
    put(23, 'n');
    put(24, 'o');
    put(25, 'p');
    put(26, 'q');
    put(27, 'r');
    put(28, 's');
    put(29, 't');
    put(30, 'u');
    put(31, 'v');
    put(32, 'w');
    put(33, 'x');
    put(34, 'y');
    put(35, 'z');
  }};
  
  public static String convertBase(String strNumber, int targetBase){
    return convertBase(strNumber, 10, targetBase);
  }
  public static String convertBase(int number, int targetBase){
    return convertBase(Convert.string(number), 10, targetBase);
  }
  public static String convertBase(int number, int currentBase, int targetBase){
    return convertBase(Convert.string(number), currentBase, targetBase);
  }
  public static String convertBase(String strNumber, int currentBase, int targetBase){
    if (currentBase<2 || targetBase<2){
      throw new Error("a numeric base can not be less than 2:\nbases passed in:"+ currentBase+ ", "+ targetBase);
    }
    if (currentBase== targetBase)   {return strNumber;}
    if (strNumber.equals("0"))      {return "0";}

    char[] charArrNumber= Convert.charArr(strNumber);

    if (currentBase== 10){
      int number= Convert.integer(strNumber);
      String refill= "";
      
      while (number> 0){
        refill= General.prepend(numberToChar.get(number% targetBase), refill);
        number/= targetBase;
      }
      
      return refill;
    }

    else{
      // conversion to base 10
      int refill= 0;
      for (int i=0; i<charArrNumber.length; i++){
        refill+= charToNumber.get(Character.toLowerCase(charArrNumber[charArrNumber.length-1-i]))* Math.pow(currentBase, i);
      }
  
      // conversion to the correct base with "recursion"
      return convertBase(Convert.string(refill), targetBase); 
    }
  }
}

Mini Convert library in Java

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