boolean method naming convention

Summary

・ Usable patterns-> is + adjective, has + past participle, triad present verb + noun, auxiliary verb + verb -Anti-pattern-> Yes and No are not clear naming ・ When you want to describe the subject, exceptionally the subject + triad verb

Naming convention list

is + adjective

Ask if you are in an adjective state ex) isEnabled

has + past participle

Ask if you are in a verb state ex) hasSent

3 simple verb + noun

Ask if there is a noun in the state of the verb Can be omitted if the noun is clear ex) hasError

Auxiliary verb + verb

Ask if it is possible and if it should be ex) canRemoveItems ex) shouldContinue

Added on February 21, 2019 Is there an auxiliary verb? None? I received the comment. I often see booleans that use auxiliary verbs, and I think they also apply to the general rule of starting with a verb. Therefore, I added it.

Common mistakes

Yes and No are unclear

ex) checkValid

Literary mistake (not in line with naming conventions)

ex) isEnable, existError → Correctly isEnabled, existsError

When you want to write the subject

For example, when trying to express whether a user exists with boolean, I found the following as an expression in GitLab.

public boolean userExists

public boolean isUserExists

public boolean existsUser

I like the first pattern the most. When I try to express it in English If user exists, ... because. Since there is a rule to start with a verb in principle, there may be a second or third pattern, but it seems strange as an English grammar, so I do not use it much.

There was also a discussion about naming conventions when having a subject on stackOverflow. https://stackoverflow.com/questions/1566745/boolean-method-naming-readability

Even if you look at this, it seems that userExists is the most.

Also, if you have an object called user, you should write user.exists ().