How To Run Enumset Inward Coffee Alongside Example

EnumSet is i of the specialized implementation of Set interface for an enumeration type, introduced inward Java 1.5 along alongside enumeration type itself. Programmer ofttimes stores Enum into mutual collection classes e.g. HashSet or ArrayList, by in addition to large because they are unaware of this piddling gem. Even I wasn't aware of this degree few years agone until I come upward across i of the finest books for Java programmers, bitwise operator. Since Enum constants are unique in addition to conduct hold pre-defined length, equally y'all tin non define a novel enum constant at runtime; it allows Java API designer to highly optimize EnumSet.

If y'all await closely, EnumSet likewise teaches y'all a span of skilful blueprint practices to do flexible in addition to maintainable code. For example, EnumSet is an abstract class, in addition to it provides lots of static manufacturing works life method to do an instance of EnumSet e.g. EnumSet.of(...). This method takes wages of method overloading in addition to variable argument to render Set of exclusively provided Enum constants.

Second skilful matter is at that topographic point are 2 concrete subclasses of EnumSet e.g. RegularEnumSet and JumboEnumSet, but both are package-private, which agency a customer tin non role them directly.

The exclusively way to role them is via EnumSet. At runtime, depending upon the key size of requested Enum, implementation automatically determine which implementation to use. This provides y'all immense flexibility in addition to command to gyre out a novel improve version of EnumSet implementation without whatever alter on the customer side.

Anyway, this article is non but virtually blueprint lessons from this degree but to a greater extent than importantly how in addition to when to role EnumSet inward Java program. I conduct hold shared a uncomplicated instance to demonstrate the mightiness of EnumSet, which y'all volition run into inward side past times side section.

EnumSet Example inward Java

In this example, nosotros conduct hold used basic colours RED, GREEN in addition to BLUE to do a custom color past times using EnumSet. As I said, EnumSet is real skilful for combining effects, whether it's text styles e.g. BOLD and UNDERLINE, equally described inward Effective Java, or combining basic colours to do custom color here. If y'all conduct hold MS paint, y'all tin fifty-fifty seek the combination of colours e.g. y'all tin combine RED and BLUE to do YELLOW, combine all 3 to do WHITE, or combining RED and BLUE to do PINK.

import java.util.EnumSet; import java.util.Set;  /**  * Simple Java Program to demonstrate how to role EnumSet.  * It has about interesting role cases in addition to it's specialized collection for  * Enumeration types. Using Enum alongside EnumSet volition orbit y'all far improve  * functioning than using Enum alongside HashSet, or LinkedHashSet.  *  * @author Javin Paul  */ world class EnumSetDemo {      private enum Color {         RED(255, 0, 0), GREEN(0, 255, 0), BLUE(0, 0, 255);         private int r;         private int g;         private int b;         private Color(int r, int g, int b) {             this.r = r;             this.g = g;             this.b = b;         }         world int getR() {             return r;         }         world int getG() {             return g;         }         world int getB() {             return b;         }     }       world static void main(String args[]) {         // this volition pull trouble inward yellowish color         EnumSet<Color> yellowish = EnumSet.of(Color.RED, Color.GREEN);         drawLine(yellow);         // RED + GREEN + BLUE = WHITE         EnumSet<Color> white = EnumSet.of(Color.RED, Color.GREEN, Color.BLUE);         drawLine(white);         // RED + BLUE = PINK         EnumSet<Color> pinkish = EnumSet.of(Color.RED, Color.BLUE);         drawLine(pink);     }       world static void drawLine(Set<Color> colors) {         System.out.println("Requested Colors to pull lines : " + colors);         for (Color c : colors) {             System.out.println("drawing trouble inward color : " + c);         }     } }  Output: Requested Colors to draw lines : [RED, GREEN] drawing trouble inward color : RED drawing trouble inward color : GREEN  Requested Colors to pull lines : [RED, GREEN, BLUE] drawing trouble inward color : RED drawing trouble inward color : GREEN drawing trouble inward color : BLUE  Requested Colors to pull lines : [RED, BLUE] drawing trouble inward color : RED drawing trouble inward color : BLUE

Important properties of EnumSet inward Java

Like whatever other Collection class, EnumSet likewise has about especial properties, which aid y'all to determine when to role EnumSet inward your Java application. Keep a authorities notation of these properties, behaviours:

1) EnumSet is a especial Set implementation, exclusively applicable for Enums inward Java, but y'all tin exclusively shop instances of the unmarried enum type. Adding an instance of dissimilar enum volition final result inward compile fourth dimension error, equally EnumSet render type-safety.

2) EnumSet internal representation is extremely efficient in addition to represented equally chip vectors. Library itself chooses i of 2 implementations available depending upon the size of a key universe. RegularEnumSet has chosen if a number of instances are less than 64, otherwise JumboEnumSet is used.

3) As described inward Effective Java, EnumSet tin hold upward safely used equally a type-safe choice of traditional int based "bit flags". EnumSet provides much-needed readability, without compromising performance.

4) Iterator returned past times EnumSet traverse the elements inward their natural order, i.e. the social club on which enum constants are declared, or the social club returned past times ordinal() method.

5) An EnumSet iterator is weakly consistent in addition to never throws ConcurrentModificationException, in addition to may or may non demo the number of whatever change to the Set land the iteration is inward progress.

6) EnumSet is likewise non synchronized inward Java. Though if y'all need, y'all tin brand EnumSet synchronized similar to other collection past times using utility methods from Collections class. Here is how to do that :

Set<YourEnum> s = Collections.synchronizedSet(EnumSet.noneOf(YourEnum.class));

7) EnumSet is an abstract class, which agency y'all cannot do its instance using new() operator. This is genuinely carefully idea to render especial implementation, in addition to that's why EnumSet provides several static manufacturing works life methods for creating instance e.g. noneOf() returns an empty EnumSet alongside specified enum type, EnumSet.of(....) returns Set of specified enum constants in addition to allOf() method creates an enum laid upward containing all elements of specified enum.

8) EnumSet likewise provides methods similar complementOf(EnumSet es) in addition to copyOf(EnumSet es) to do EnumSet from other EnumSet, coplementOf() returns enum laid upward alongside containing all the elements of this type that are non contained inward the specified set.

That's all virtually EnumSet inward Java. It's i of the useful class, which is perfect for for sure role cases, but it likewise teaches a lot of lesson on degree blueprint in addition to role of the package. I genuinely similar how they shielded implementation degree RegularEnumSet in addition to JumboEnumSet in addition to provides manufacturing works life methods to do EnumSet. This way news of choosing implementation remains alongside the library itself, past times making both of these classes package-private, at that topographic point is no worry of the customer direct accessing them. You tin role EnumSet to function past times arguments to methods in addition to to do meaningful groups from enum.

Further Learning
Java In-Depth: Become a Complete Java Engineer
Java Fundamentals: Collections
Data Structures in addition to Algorithms: Deep Dive Using Java
Algorithms in addition to Data Structures - Part 1 in addition to 2
Data Structures inward Java nine past times Heinz Kabutz

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