Jan 17, 2011 · Why to use enum. enums are implicitly final subclasses of java.lang.Enum; if an enum is a member of a class, it's implicitly static; new can never be used with an enum, even within the enum type itself; name and valueOf simply use the text of the enum constants, while toString may be overridden to provide any content, if desired

Mar 24, 2012 · it also allows you to add arbitrary methods and fields to an enum type, to implement arbitrary interfaces, and more. Enum types provide high-quality implementations of all the Object methods. They are Comparable and Serializable, and the serial form is designed to withstand arbitrary changes in the enum type. You can also use Enum in switch case.

One of the Sonar rules is Enum values should be compared with "==". The reasons are as follows: Testing equality of an enum value with equals() is perfectly valid because an enum is an Object and every Java developer knows == should not …

Sep 14, 2009 · or you can pass in 11 to a function expecting a suit. You can't do that with a typesafe enum. You can use a class for Suit to provide type safety and this was the solution before Java 5. Josh Bloch (in Effective Java, which is a must read for Java programmers imho) promoted the typesafe enum pattern that became the Java 5+ enum. It has a fair ...

Yes add the string into the enum's constructor (specify a constructor in the enum which takes a String) and create the enums with a text value of a, b , c. Etc. Then implement a static factory method on the enum which takes a string and returns the enum instance. I …

Nov 13, 2011 · Use a list of static final ints rather than a type-safe enum and switch on the int value you receive (this is the pre-Java 5 approach) Switch on either a specified id value (as described by heneryville ) or the ordinal value of the enum values; i.e. guideView.GUIDE_VIEW_SEVEN_DAY.ordinal()

Sep 11, 2013 · In your method implementation PerspectiveCommands is not the enum but your type parameter, which often is called T. It thus shadows the enum of the same name like axtavt already said, thus PERSPECTIVE is unknown here. Your abstract method declaration is fine but you might use a slightly different approach.

Using an enum is absolutely the right thing to do to restrict the user type to only one of a set of constants that are all known at compile time. However, the Java convention for naming both static final fields and enum constants is to use ALL_UPPER_CASE with words separated by …

You can't. Java doesn't allow generic types on enum constants. They are allowed on enum types, though: public enum B implements A<String> { A1, A2; } What you could do in this case is either have an enum type for each generic type, or 'fake' having an enum by just making it a class:

Mar 9, 2019 · Enum is better to use for type safety. Wrong values cannot be entered. But enum in android takes so much memory, you should use intdef instead. Refer to this answer for Example and explanation:-IntDef/StringDef Example. You can also check android source code it is replacing enums with IntDef/StringDef wherever possible. Ex. View.VISIBLE.