Names just repeat the types - if types are correct and methods are small
The same object should have the same name when passed to other methods - not always but usually
Prefer positive conditional names - e.g. avoid !isNot()_
Some conventions
Class name: noun
Method name: verb
Avoid prefixes and technical terms (e.g. Abstract)
Name length corresponds scope length
Old Enterprise JavaBeans - EJB
Comply with: Java Code Conventions (Sun, 1997)
EJB - Enterprise JavaBeans
private Foo foo - foo is a 'property' name
public Foo getFoo() - the property name with a capital
public void setFoo(Foo foo)
public boolean isSomething() - also hasSomething()
Example: Bad: Names
class DtaRcrd102 {
// Not meaningful, not readable, not pronounceable
Date genymdhms;
Date modymdhms;
String pszqint = "102";
// Avoid prefixes and Hungarian notation
String m_dsc;
String strName;
// Hard to read
XYZControllerForEfficientStorageOfStrings con1;
XYZControllerForEfficientHandlingOfStrings con2;
// Disinforming
void setName(String name) {
m_dsc = name;
}
// Not informative
void doCalculation() {
// Too short names, Magic numbers
for (int j=0; j<34; j++) {
s += (t[j]*4)/5;
}
}
}
Example: Good: Names
class Customer {
private String description;
private Date generationTimestamp;
private Date modificationTimestamp;;
private final String recordId = "102";
int realDaysPerIdealDay = 4;
const int WORK_DAYS_PER_WEEK = 5;
int sum = 0;
void setDescription(String description) {
this.description = description;
}
int calculateWeeks() {
for (int j=0; j < NUMBER_OF_TASKS; j++) {
int realTaskDays = taskEstimate[j] * realDaysPerIdealDay;
int realTaskWeeks = (realdays / WORK_DAYS_PER_WEEK);
sum += realTaskWeeks;
}
return sum;
}
}
Example: Bad: Not informative names
// What does it really do?
assertThat(scores, is(StudentService.collectScores(STUDENT_LIST2)));
Example: Good: Informative names
// Readable: "It creates an empty score list from an empty student list"
assertThat(emptyScoreList, is(StudentService.collectScores(STUDENT_LIST_EMPTY)));
Example: Bad: Not informative name of input parameter
// What kind of input value is converted?
// It is not a 'find' but rather a 'convert'
private String findDeadlineType(int i) {
String result;
switch (i) {
case 0:
result = RK_FIRST_NAME_DEADLINE;
break;
case 1:
result = RK_SECOND_NAME_DEADLINE;
break;
default:
result = ""; //future values come here
break;
}
return result;
}
// Best practice: Refactor to enum
Example: Bad: Confusing characters (From the book)
int a = l;
if ( O == l )
a = O1;
else
l = 01;
Example: Good: Name lengths correspond to scope
// The class is one screen long
@Component
public class NameDeadlineReminderMessageCollector {
@Autowired
private DeadlineReminderMessagePnrFilter filter; // Used only in this class
@Autowired
private DeadlineReminderMessageSorter sorter; // Used only in this class
@Transactional(readOnly = true)
public List<DeadlineReminderMessage> collectDeadlineRemindersByAgency(String agencyInternalId) {
return sorter.sort(filter.filter(findDeadlines(agencyInternalId), findPnrs(agencyInternalId)));
}
@Transactional(readOnly = true)
public List<DeadlineReminderMessage> collectDeadlineRemindersByPoses(List<String> poses) {
return sorter.sort(filter.filter(findDeadlines(poses), findPnrs(poses)));
}
}
