Sweetener - Strings
There is no person who would not know the String class. To facilitate the work of this class, has been created ‘Strings’. We have created such methods as : join, numberOfOccurrences, removeAllOccurrences, indexesOf, groups, random, pad, capitalize, capitalizeAllWords, isWhitespace, containsOnly, isEmpty, singleLine, removeNewLines, reverse, repeat, isAlpha, isAlphaWithWhitespace, isNumeric, isAlphanumeric, isAlphanumericWithWhitespace
join
There are two methods responsible for created String from given collection or array of object:
String join(String separator, Collection<?> collection)
String join(String separator, Object... args)For each object from collection is invoked toString() method. If given object is null, to resulting string is added the ‘null’ value.
Examples
List<String> strings = new ArrayList<String>();
strings.add("A");
strings.add("B");
strings.add("C");
strings.add("D");
String result = Strings.join(", ", strings);
// result: "A, B, C, D"class Person {
...
@Override
public String toString() {
return "Person [name=" + name + ", lastName=" + lastName + "]";
}
}
List<Person> people = new ArrayList<Person>();
people.add(new Person("John", "Deep", 19, null, null));
people.add(null);
people.add(new Person("Marry", "Duke", 21, null, null));
String result = Strings.join(", ", people);
// result: "Person [name=John, lastName=Deep], null, Person [name=Marry, lastName=Duke]"Number of occurrences
To check the number of occurrences of a sequence in the String you can use one of the following methods:
public static int numberOfOccurrences(String sourceObject, String sequence);
public static int numberOfOccurrences(String sourceObject, String sequence, boolean ignoreRegexp);
public static int numberOfOccurrences(String sourceObject, Character sequence);
public static int numberOfOccurrences(String sourceObject, Character sequence, boolean ignoreRegexp);As you can see, each method has its own version of ignoring the regular expression. Sometimes you want to search of dots, but what happens when you directly pass the “.” as parameter ? Will be returned all the characters, because dot represents any char. Fortunately, you can easily fix this now. Look at the following example:
String sourceString = "ab.ac.ad.";
int numberOfCccurrences = Strings.numberOfOccurrences(sourceString, "."); // numberOfCccurrences = 9
numberOfCccurrences = Strings.numberOfOccurrences(sourceString, ".", true); // numberOfCccurrences = 3Remove all occurrences
This method is very similar to the previous method and also has four variants.
public static String removeAllOccurrences(String sourceObject, String sequence);
public static String removeAllOccurrences(String sourceObject, String sequence, boolean ignoreRegexp);
public static String removeAllOccurrences(String sourceObject, Character sequence);
public static String removeAllOccurrences(String sourceObject, Character sequence, boolean ignoreRegexp);String sourceString = "ab.ac.ad.";
String emptyString = Strings.removeAllOccurrences(sourceString, "."); // ""
String stringWithoutDots = Strings.removeAllOccurrences(sourceString, ".", true); // "abacad"Indexes of
If you want to get all of the indexes given occurrences, this method is right for you.
public static List<Integer> indexesOf(String sourceObject, String sequence, boolean ignoreRegexp);
public static List<Integer> indexesOf(String sourceObject, String sequence);
public static List<Integer> indexesOf(String sourceObject, Character c, boolean ignoreRegexp);
public static List<Integer> indexesOf(String sourceObject, Character c);String sourceString = "ab.ac.ad.";
List<Integer> indexesOf = Strings.indexesOf(sourceString, "."); // [0, 1, 2, 3, 4, 5, 6, 7, 8]
List<Integer> indexesOf = Strings.indexesOf(sourceString, ".", true); // [2, 5, 8] Groups
This method is very similar to the above, but there’s returned a more detailed information.
String sourceString = "ab.ac.ad.";
List<FoundGroup> groups = Strings.groups(sourceString, ".");
// [[startIndex=0, endIndex=1, content=a], [startIndex=1, endIndex=2, content=b], [startIndex=2, endIndex=3, content=.], [startIndex=3, endIndex=4, content=a], [startIndex=4, endIndex=5, content=c], [startIndex=5, endIndex=6, content=.], [startIndex=6, endIndex=7, content=a], [startIndex=7, endIndex=8, content=d], [startIndex=8, endIndex=9, content=.]]
List<FoundGroup> groups = Strings.groups(sourceString, ".", true);
// [[startIndex=2, endIndex=3, content=.], [startIndex=5, endIndex=6, content=.], [startIndex=8, endIndex=9, content=.]]Random
Have you ever tried to look for a method that would generate a random string for you? That’s right, there is no such method! Fortunately sweetener provides two such methods:
public static String random(int length);
public static String random(List<Character> symbols, int length);The first one generates a random string of: a-z A-Z 0-9 Whereas the second takes a list of characters used in generation.
List<Character> symbols = Collections.newArrayList('@', '!', '*', '^', '%', '(', ')', ',', '.', '?');
String random = Strings.random(symbols, 7); // ^)?!)%@
String random = Strings.random(7); // unDys83Pad
public static String pad(String sourceObject, int length);
public static String pad(String sourceObject, int length, PaddingType paddingType);
public static String pad(String sourceObject, Character c, int length);
public static String pad(String sourceObject, Character c, int length, PaddingType paddingType);
public static String pad(String sourceObject, String content, int length);
public static String pad(String sourceObject, String content, int length, PaddingType paddingType);The default fill character (character c or string content) is a space.
PaddingType property determines whether the padding should be on the left, right or central - the default is right.
String result = Strings.pad("abc", "*-", 7, PaddingType.CENTRE); // "-*abc*-"
String result = Strings.pad("abc", "*-", 7, PaddingType.LEFT); // "-*-*abc"
String result = Strings.pad("abc", "*-", 7, PaddingType.RIGHT); // "abc*-*-"Capitalize
public static String capitalize(String value);
public static String capitalizeAllWords(String value);Is whitespace
public static boolean isWhitespace(char c);
public static boolean isWhitespace(String c);Contains only
This method returns an indication whether the specified string consists exclusively of characters passed as the second argument.
public static boolean containsOnly(String value, List<Character> listOfCharacters);Is empty
This method returns true if value is null, empty or consists of only whitespaces.
public static boolean isEmpty(String value);Single line
This method removes all occurrences of characters: \n \r. As a result returned is a single line.
public static String singleLine(String value);Remove new lines
This method removes the newline at the end of the String.
public static String removeNewLines(String value);Reverse
This method reverses the string.
public static String reverse(String value);Repeat
This method repeat given sequence specified number of times.
public static String repeat(String value, int numberOfRepeats);Is alpha, alphaWithWhitespace, numeric, alphanumeric, alphanumericWithWhitespace
public static boolean isAlpha(String value);
public static boolean isAlphaWithWhitespace(String value);
public static boolean isNumeric(String value);
public static boolean isAlphanumeric(String value);
public static boolean isAlphanumericWithWhitespace(String value);
