[JAVA] To be aware of easy-to-read code

Be aware of easy-to-read code

If you're not careful, it tends to be redundant code, so for awareness We have summarized the points to improve readability.

Simplify conditional expressions

java

if (a == 1 && b == 2 && c == 3 && d == 4){
  System.out.println("test");
}

//Wrap a conditional expression in an if statement

if (a == 1 && 
   b == 2 &&
   c == 3 &&
   d == 4){
  System.out.println("test");
}

//Create methods to improve readability
if (output()){
  System.out.println("test");
}

private boolean isValidType(){
//processing
return true;
}

Nesting too deep

java

//NG
if(a == 1){
    if(b == 2){
        if(c == 3){
            if(d == 4){
                if(e == 5){
                   System.out.println("test");
                }
            }
        }
    }
}

//OK
////Create the same method to improve readability
if (isValidType()){
  System.out.println("test");
}

private boolean isValidType(){
//processing
return true;
}

Inappropriate variable or method name

Declared according to naming convention

Snake case

java

String user_name = "Taro"

Lower camel case

java

String userName = "Taro"

Upper camel case

java

String UserName = "Taro"

Chain case

java

String user-name = "Taro"

Automatically create variable names using codic

Awareness of scope scope

java

//NG
class Calculator {
  public static int num = 0;
  public static void alterNumber(int _num) {
    num = _num;
  }
  public static void main(String args[]) {
    alterNum(23);
  }
}

//OK
//Can only be executed within a class due to access control
class Calculator {
  private static int num = 0;
  private static void alterNumber(int _num) {
    num = _num;
  }
  public static void main(String args[]) {
    alterNum(23);
  }
}

Code integration

java

//NG
public class StandAction extends BaseAction {
  public void Stand(Account account) {
    if(account.getFirstName() == null || account.getFirstName().length()== 0) {
      return;
    }
    if(account.getLastName() == null || account.getLastName().length() == 0) {
      return;
    }
  }
}


//OK
//Added methods to improve readability
public class Stand extends BaseAction {
  public void Stand(Account account){
    if(isEmpty(account.getFirstName())){
      return;
    }
    if(isEmpty(account.getLastName())) {
      return;
    }
  }
  public boolean isEmpty(String str) { 
    return str == null || str.length() == 0;
  }
}