Enums are powerful data structures with named constants that can serve as valuable tools in a range of programming designs. They are often used to maintain a centralized collection of default values.<\/p>\n
As enum definitions grow more complex, the means of conveniently accessing more complex data requires greater levels of effort. Enums also called enumeration or, in the case of Ruby,\u00a0factor<\/em>, are a common datatype provided by most modern programming languages<\/a>.<\/p>\n Python, being a notable exception, still provides a functional equivalent via its dictionary datatype. Given, implementation is quite different. To illustrate the functionality of enums common to C++, C#, and Java<\/a>, the following examples demonstrate how to access enum values explicitly via custom accessor methods.<\/p>\n The following code creates a new Enum class named This is a fine start but doesn’t address possible use cases where convenient access to the positional values would be needed. For example, the following code illustrates a minimal implementation of an instance of the Note that the resulting output to standard out is the Enums provide methods by which one can iterate through values but no standard means by which to access named values data. In the code below, the In this example code, the accessor methods At first glance, I felt the lack of standardized access to enum values was a massive downside to the data structure. However, I quickly realized the requirement of custom implementation provided enums a much more dynamic range of applications<\/a>. Requiring custom accessor methods to named values opens up enums for a wider (if not endless) range of possible data representations.<\/p>\n Enumerated values (enums) were not always standard parts of programming languages. Before their conception, constants were often assigned default values (a.k.a.\u00a0magic numbers<\/em>). Enums were a solution to provide a more self-documenting means to incorporate constants and standardized values into large-scale software<\/a>.<\/p>\n The examples of Java enums here illustrate a basic definition of an enum class that leverages the power of custom accessor methods. While simple in concept, this approach provides endless means for developers to conveniently access the values of an Enum.<\/p>\n","protected":false},"excerpt":{"rendered":" Enums are powerful data structures with named constants that can serve as valuable tools in a range of programming designs. They are often used to maintain a centralized collection of default values. As enum definitions grow more complex, the means of conveniently accessing more complex data requires greater levels of effort. Enums also called enumeration […]<\/p>\n","protected":false},"author":2,"featured_media":2472,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"categories":[655,10],"tags":[302,301,172,20],"acf":[],"_links":{"self":[{"href":"https:\/\/www.alpharithms.com\/wp-json\/wp\/v2\/posts\/711"}],"collection":[{"href":"https:\/\/www.alpharithms.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.alpharithms.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.alpharithms.com\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.alpharithms.com\/wp-json\/wp\/v2\/comments?post=711"}],"version-history":[{"count":1,"href":"https:\/\/www.alpharithms.com\/wp-json\/wp\/v2\/posts\/711\/revisions"}],"predecessor-version":[{"id":712,"href":"https:\/\/www.alpharithms.com\/wp-json\/wp\/v2\/posts\/711\/revisions\/712"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.alpharithms.com\/wp-json\/wp\/v2\/media\/2472"}],"wp:attachment":[{"href":"https:\/\/www.alpharithms.com\/wp-json\/wp\/v2\/media?parent=711"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.alpharithms.com\/wp-json\/wp\/v2\/categories?post=711"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.alpharithms.com\/wp-json\/wp\/v2\/tags?post=711"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Basic Enum Example<\/h2>\n
Letter<\/code> which defines a collection of alphabetical letters (A-E) as the set of named values. In this instance, Letter<\/code> defines its values as a tuple consisting of two values: a single char<\/code> and a single int<\/code>. These represent the character value associated with a letter<\/code> and its numerical position<\/code> in the [English] alphabet.<\/p>\nenum Letter{\r\n\r\n \/\/ Define enum values\r\n A('a', 1),\r\n B('b', 2),\r\n C('c', 3),\r\n D('d', 4),\r\n E('e', 4);\r\n\r\n \/\/ Declare values\r\n char letter;\r\n int position;\r\n\r\n \/\/ Default constructor\r\n Letter(char letter, int position) {\r\n this.letter = letter;\r\n this.position = position;\r\n }\r\n}<\/pre>\nLetter<\/code> enum:<\/p>\npublic static void main(String[] args) {\r\n \r\n \/\/ Create an instance of Letter\r\n Letter myLetter = Letter.A;\r\n\r\n \/\/ Print the new instance's default representation\r\n System.out.println(myLetter); \r\n\r\n}\r\n\r\n\/\/ Resulting Output\r\nA<\/pre>\nString<\/code> representation of the named constant\u2014not the defined char representation. In other words, if the named value of A<\/code> were instead AYE<\/code> the resulting output would have been AYE<\/em>. This behavior is expected and defined in the official Java Enum documentation<\/a>.<\/p>\nCustom Accessor Methods<\/h2>\n
Letter<\/code> enum has been expanded to provide convenient access to both the letter<\/code> and position<\/code> values of a Letter<\/code> instance.<\/p>\nenum Letter{\r\n\r\n \/\/ Define enum values\r\n A('a', 1),\r\n B('b', 2),\r\n C('c', 3),\r\n D('d', 4),\r\n E('e', 4);\r\n\r\n \/\/ Declare values\r\n char letter;\r\n int position;\r\n\r\n \/\/ Default constructor\r\n Letter(char letter, int position) {\r\n this.letter = letter;\r\n this.position = position;\r\n }\r\n\r\n \/\/ Accessor method for letter\r\n public char getLetter(){\r\n return this.letter;\r\n }\r\n\r\n \/\/ Accessor method for position\r\n public int getPosition(){\r\n return this.position;\r\n }\r\n}<\/pre>\ngetLetter<\/code> and getPosition<\/code> allow direct access to the named values tuples. This allows one to access both the char<\/code> representation and int<\/code> position value as letterInstance.getLetter()<\/code> or letterInstance.getPosition()<\/code>. To better illustrate this, the following example code iterates through all values in the Letter<\/code> enum printing the position and character value.<\/p>\npublic static void main(String[] args) {\r\n\r\n \/\/ Iterates through all Letter values (A-E)\r\n for (Letter l: Letter.values()) {\r\n\r\n \/\/ Output each letter and position value as a formatted string.\r\n System.out.println(\r\n MessageFormat.format(\r\n \"Letter: {0}, Positions: {1}\",\r\n l.getLetter(), l.getPosition()));\r\n }\r\n}\r\n\r\n\/\/ Resulting output\r\nLetter: a, Positions: 1\r\nLetter: b, Positions: 2\r\nLetter: c, Positions: 3\r\nLetter: d, Positions: 4\r\nLetter: e, Positions: 4<\/pre>\nFinal Thoughts<\/h2>\n