CR-MicroLabs-JavaFundamentals-DanDoBetterDrills/StringUtilities.java

 import java.util.*;

/**
 * Created by dan on 6/14/17.
 */
public class StringUtilities {
    /**
     * @return `Hello World` as a string
     */
    public static String getHelloWorld() {
        return "Hello World";
    }

    /**
     * @param firstSegment a string to be added to
     * @param secondSegment a string to add
     * @return the concatenation of two strings, `firstSegment`, and `secondSegment`
     */
    public static String concatenation(String firstSegment, String secondSegment){
        return firstSegment + secondSegment;
    }

    /**
     * @param firstSegment a string to be added to
     * @param secondSegment a string to add
     * @return the concatenation of an integer, `firstSegment`, and a String, `secondSegment`
     */
    public static String concatenation(int firstSegment, String secondSegment){
        return String.valueOf(firstSegment + secondSegment);
    }

    /**
     * @param input a string to be manipulated
     * @return the first 3 characters of `input`
     */
    public static String getPrefix(String input){
        return input.substring(0,3);
    }

    /**
     * @param input a string to be manipulated
     * @return the last 3 characters of `input`
     */
    public static String getSuffix(String input){
        return input.substring((input.length())-3);
    }

    /**
     * @param inputValue the value to be compared
     * @param comparableValue the value to be compared against
     * @return the equivalence of two strings, `inputValue` and `comparableValue`
     */
    public static Boolean compareTwoStrings(String inputValue, String comparableValue){
        return inputValue.equals(comparableValue);
    }

    /**
     * @param inputValue the value input from user
     * @return the middle character of `inputValue`
     */
    public static Character getMiddleCharacter(String inputValue){
        int charNum = inputValue.length();
        int middleIndex = 0;
        if (charNum%2 == 1){middleIndex = (charNum/2);}
        else {middleIndex = (charNum/2)-1;}
        
        return (char)inputValue.charAt(middleIndex);
    }

    /**
     * @param spaceDelimitedString a string, representative of a sentence, containing spaces
     * @return the first sequence of characters
     */
    public static String getFirstWord(String spaceDelimitedString){
        int spaceIndex=0;
        spaceIndex = spaceDelimitedString.indexOf(" ");
        
        return spaceDelimitedString.substring(0,spaceIndex);
    }

    /**
     * @param spaceDelimitedString a string delimited by spaces
     * @return the second word of a string delimited by spaces.
     */
    public static String getSecondWord(String spaceDelimitedString){
        int spaceIndex = spaceDelimitedString.indexOf(" ");
        
        return spaceDelimitedString.substring(spaceIndex+1);
    }

    /**
     * @param stringToReverse
     * @return an identical string with characters in reverse order.
     */
    public static String reverse(String stringToReverse){
        String reverse = "";
        for (int i= stringToReverse.length()-1; i>=0; i--){
            reverse += stringToReverse.charAt(i);
        }
        return reverse;
    }
}