What is the best practice for the Java constants class?
create a constant class by looking at some of the best practices described here in stackoverflow. Many of those have a single Constant class with variables. Some of the answers suggested creating separate Contant Classes. The way I create a constant class is by naming it Parameters and creating classes i.e. Variables and Constants. Then these classes further have child classes e.g. URL, Columns etc. This time I created a constant class with the same structure and a separate class named ReportTemplate. This is my first time creating a Constant class of Objects that don't have a primitive data type.
public final class ReportTemplate {
public final static class ColumnIds {
public static final String TITLE_COLUMN_ID = "title";
public static final String TYPE_COLUMN_ID = "type";
public static final String LIFECYCLESTATUS_COLUMN_ID = "lifecyclestatus";
public static final String INSERTIONTIMESTAMP_COLUMN_ID = "insertionTimestamp";
}
public final static class Columns {
public static final TextColumnBuilderTITLE = col.column( "Title", ColumnIds.TITLE, type.stringType());
public static final TextColumnBuilderLIFECYCLESTATUS = col.column( "Lifecycle Status", ColumnIds.LIFECYCLESTATUS,
type.stringType());
public static final TextColumnBuilderTYPE = col.column("Type", ColumnIds.TYPE, type.stringType());
public static final TextColumnBuilderINSERTIONTIMESTAMP = col .column("Insertion Timestamp",
ColumnIds.INSERTIONTIMESTAMP,
type.stringType());
}
public final static class Styles {
public static final StyleBuilder HEADING1 = stl.style()
.setName("heading1").bold().setFontSize(15);
public static final StyleBuilder HEADING2 = stl.style().setName("heading2")
.bold().setFontSize(12);
public static final StyleBuilder HEADING3 = stl.style().setName("heading3")
.bold().setFontSize(10);
}
}
I want to know if my
Naming Scheme is correct
Constant class structure is among best practices.
Should I create separate constant classes or having them encapsulated in a parent Constant class is fine?
Is the Naming Scheme correct? -
Ideally you should not create a class with names like Variables, Parameters, etc. as these names also have literal meanings with them in many languages. Besides that, these classes are going to store Constants! You can simply create a single class with the name Constants! No need to create different Constant classes till it's absolutely necessary. Perhaps, in that case you should go for enums. Why? Check these link -
https://gorbeia.wordpress.com/2015/03/11/java-enums-vs-constants/
Java constant class structure is among best practices ?This is answered in the above point. Keep your naming convention readable enough so that you won't require separate constant classes. Always try to implement KISS(Keep it Simple Stupid) and DRY(Don't repeat yourself!) Should I create separate constant classes or have them encapsulated in a parent Constant class is fine? Ideally not. If you need such a requirement then go for enums. As enums are typesafe, you wont end up creating misleading statements. For example, If you write following potentially incorrect code then Constant class won't mind:
String playerType = Constants.MALE;
But, if you use enums, that would end up as:
// Compile-time error - incompatible types!
PlayerType playerType = Gender.MALE;Answer (1)
The use of a Constants class in Java is a common practice for storing constant values used throughout an application. Here are some best practices for creating and using a Constants class in Java:
Use final keyword: Declare constant fields in your Constants class using the final keyword to indicate that their values cannot be changed once initialized.
Private constructor: Make the constructor of your Constants class private to prevent instantiation. This ensures that the class is used only for accessing constants and not for creating objects.
Use a naming convention: Name your Constants class in a way that clearly indicates its purpose and content. For example, if your constants are related to configuration settings, you might name the class ConfigConstants.
Group related constants: Organize your constants logically within the Constants class. You can use static nested classes, enums, or simply grouping them together based on functionality or usage.
Avoid magic numbers: Instead of using literal values directly in your code, define them as constants in your Constants class with descriptive names. This improves code readability and makes it easier to understand the purpose of each value.
Use meaningful names: Choose descriptive names for your constants that convey their purpose or meaning. This helps improve code clarity and makes maintenance easier.
Document constants: Provide comments or documentation for each constant to explain its purpose or usage. This helps other developers understand the significance of each constant.
Avoid overuse: While Constants classes can be useful for storing commonly used values, avoid overusing them for every single constant in your code. Reserve them for values that are truly constant across your application.
Consider alternatives: In some cases, alternatives like enums or configuration files may be more appropriate for managing constants, depending on the nature of your constants and their usage within the application.
Refrain from modifying constants at runtime: Constants are meant to be immutable. Modifying them at runtime can lead to unexpected behavior and violates the principle of constant values.
By following these best practices, you can create a well-structured and maintainable Constants class in Java that enhances the readability and maintainability of your codebase.