Coding Style Guide

General Style

• Config your IDE or editors to use white space instead of hard tabs.
  • Eclipse
  • Window->Preferences->Editors->Text Editors->Insert spaces for tabs
  • Window->Preferences->Java->Code Style->Formatter->Edit->Indentation-> Tab policy = "Spaces Only"
  • Existing tabs in the file will prevent spaces in new lines created with Enter.
  • Sublime Text: Preferences -> Settings User ->

    "tab_size": 4,
    "translate_tabs_to_spaces": true,

• Notepad++: Settings -> Preferences -> Tab Settings -> "Replace by space"
• Line length in Eclipse
  Window->Preferences->Java->Code Style->Formatter->Edit->Line Wrapping->Max line width: 100
• Indent for wrapped lines
  Window->Preferences->Java->Code Style->Formatter->Edit->Line Wrapping-> Default indentation for wrapped lines: 1
• White spaces
• Separating any reserved word from an open parenthesis ( that follows it on that line, if, for, catch, while.
• Separating any reserved word from a closing curly brace } that precedes it on that line, such as else or catch
• Before any open curly brace {

if (a = b) {
       // code
} else {
       // code
}

• On both sides of any binary or ternary operator.

int name = "Mary"
foreach (int num : array)

• After ,:; or the closing parenthesis ) of a cast

void funcName(int foo, int bar)

• Braces
• Braces are used with if, else, for, do and while statements, even when the body is empty or contains only a single statement.
• No line break before the opening brace.
• Line break after the opening brace.
• Line break before the closing brace.
• Line break after the closing brace, only if that brace terminates a statement or terminates the body of a method, constructor, or named class. For example, there is no line break after the brace if it is followed by else or a comma.

return new MyClass() {
        @Override public void method() {
            if (condition()) {
                try {
                    something();
                } catch (ProblemException e) {
                    recover();
                }
            } else if (otherCondition()) {
                somethingElse();
            } else {
              lastThing();
            }
        }
};    

• Line wrapping
• The prime directive of line-wrapping is: prefer to break at a higher syntactic level
• When a line is broken at a non-assignment operator the break comes before the symbol.
• When a line is broken at an assignment operator the break typically comes after the symbol
• A method or constructor name stays attached to the open parenthesis ( that follows it.
• A comma , stays attached to the token that precedes it.

        myResult = this.thisIsAVeryLongMethodNameBlaBlaBlaBlaBla(
            parameter1, parameter2, parameter3, parameter4, parameter5, parameter6,
            parameter7, parameter8, parameter9, parameter10, parameter11, parameter12);

• Exceptions
  • Lines where obeying the column limit is not possible (for example, a long URL in Javadoc, or a long JSNI method reference).
  • package and import statements
  • Command lines in a comment that may be cut-and-pasted into a shell.

[Google Java coding style guide]
(https://google.github.io/styleguide/javaguide.html)

SQL

• Bind parameters in SQL queries, don't use literal values.
• Prefer PreparedStatement over Statement in JDBC

sql = "SELECT t.name FROM hr.employees t WHERE employee_id = ?";
statement = connection.prepareStatement(sql);
System.out.println("Start: " + new Date());
for(int i=0; i<10000; i++) {
        statement.setInt(1, i);
        resultset = statement.executeQuery();
        if(resultset.next()) {
            name = resultset.getString("name");
            doSomething(name);
        }
        resultset.close();
    }            
System.out.println("End: " + new Date());
statement.close();

• Bind variable in sql
• Hibernate code
  Don't do this:

String endShowDateSql = "TO_DATE('"+endShowDate+"', 'Month dd, YYYY HH:MI:SS AM')";
sql = StringUtil.replace(sql, "[$END_SHOW_DATE$]", endShowDateSql);
sql = StringUtil.replace(sql, "[$DMA_CODE$]", dmaCode);

Do this:

SQLQuery q = session.createSQLQuery(sql);
q.addScalar("Id_", Type.LONG);
q.addScalar("rank", Type.FLOAT);
QueryPos qPos = QueryPos.getInstance(q);
qPos.add(classNameId);
qPos.add(ArrayUtils.toPrimitive(siteIds.toArray(new Long[siteIds.size()])));
qPos.add(companyId);