Problem
Low Cohesion
Coupling
Maintainability
Readability
Solution
Identify methods related to specific groups of attributes.
Cluster these methods together.
Break down the original class into smaller, more focused objects based on these clusters.
Replace existing references with new objects.
Examples
DTOs
Denormalized table rows
Sample Code
Wrong
class ExcelSheet (
val filename: String,
val fileEncoding: String,
val documentOwner: String,
val documentReadPassword: String,
val documentWritePassword: String,
val creationTime: LocalDateTime,
val updateTime: LocalDateTime,
val revisionVersion: String,
val revisionOwner: String,
val previousVersions: List<String>,
val documentLanguage: String,
val cells: List<Cell>,
val cellNames: List<String>,
val geometricShapes: List<Shape>,
)
Right
class ExcelSheet (
val fileProperties: FileProperties,
val securityProperties: SecurityProperties,
val datingProperties: DocumentDatingProperties,
val revisionProperties: RevisionProperties,
val languageProperties: LanguageProperties,
val content: DocumentContent,
)
// The object now has fewer attributes, resulting in improved
// testability.
// The new objects are more cohesive, more testable, and lead to fewer
// conflicts, making them more reusable. Both FileProperties and
// SecurityProperties can be reused for other documents. Additionally,
// rules and preconditions previously found in fileProperties will be
// relocated to this object, resulting in a cleaner ExcelSheet
// constructor.
Conclusion
Bloated objects know too much and are very difficult to change due to cohesion.
Developers change these objects a lot, so they bring merge conflicts and are a common problem source.
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Top comments (2)
Sounds good, just if we need to change a value on a property in a far level from base class could be a problem (data classes nested), like this:
excelSheet.copy(fileProperties = FileProperties.copy(path = fileProperties.path)), I'm seeing this code in MVI patterns inupdaterclassIn such case you can use some libraries like Arrow that giving you exactly this possibility with the usage of lens - you can find more info about it here: arrow-kt.io/learn/immutable-data/l...