itachi1706/SingBuses

Duplicated string literals make the process of refactoring error-prone, since you must be sure to update all occurrences.

On the other hand, constants can be referenced from many places, but only need to be updated in a single place.

Noncompliant Code Example

With the default threshold of 3:

public void run() {
  prepare("action1");                              // Noncompliant - "action1" is duplicated 3 times
  execute("action1");
  release("action1");
}

@SuppressWarning("all")                            // Compliant - annotations are excluded
private void method1() { /* ... */ }
@SuppressWarning("all")
private void method2() { /* ... */ }

public String method3(String a) {
  System.out.println("'" + a + "'");               // Compliant - literal "'" has less than 5 characters and is excluded
  return "";                                       // Compliant - literal "" has less than 5 characters and is excluded
}

Compliant Solution

private static final String ACTION_1 = "action1";  // Compliant

public void run() {
  prepare(ACTION_1);                               // Compliant
  execute(ACTION_1);
  release(ACTION_1);
}

Exceptions

To prevent generating some false-positives, literals having less than 5 characters are excluded.

Returning null instead of an actual array or collection forces callers of the method to explicitly test for nullity, making them more complex and less readable.

Moreover, in many cases, null is used as a synonym for empty.

Noncompliant Code Example

public static List<Result> getResults() {
  return null;                             // Noncompliant
}

public static Result[] getResults() {
  return null;                             // Noncompliant
}

public static void main(String[] args) {
  Result[] results = getResults();

  if (results != null) {                   // Nullity test required to prevent NPE
    for (Result result: results) {
      /* ... */
    }
  }
}

Compliant Solution

public static List<Result> getResults() {
  return Collections.emptyList();          // Compliant
}

public static Result[] getResults() {
  return new Result[0];
}

public static void main(String[] args) {
  for (Result result: getResults()) {
    /* ... */
  }
}

See

• CERT, MSC19-C. - For functions that return an array, prefer returning an empty array over a null value
• CERT, MET55-J. - Return an empty array or collection instead of a null value for methods that return an array or collection

Duplicated string literals make the process of refactoring error-prone, since you must be sure to update all occurrences.

On the other hand, constants can be referenced from many places, but only need to be updated in a single place.

Noncompliant Code Example

With the default threshold of 3:

public void run() {
  prepare("action1");                              // Noncompliant - "action1" is duplicated 3 times
  execute("action1");
  release("action1");
}

@SuppressWarning("all")                            // Compliant - annotations are excluded
private void method1() { /* ... */ }
@SuppressWarning("all")
private void method2() { /* ... */ }

public String method3(String a) {
  System.out.println("'" + a + "'");               // Compliant - literal "'" has less than 5 characters and is excluded
  return "";                                       // Compliant - literal "" has less than 5 characters and is excluded
}

Compliant Solution

private static final String ACTION_1 = "action1";  // Compliant

public void run() {
  prepare(ACTION_1);                               // Compliant
  execute(ACTION_1);
  release(ACTION_1);
}

Exceptions

To prevent generating some false-positives, literals having less than 5 characters are excluded.

Duplicated string literals make the process of refactoring error-prone, since you must be sure to update all occurrences.

On the other hand, constants can be referenced from many places, but only need to be updated in a single place.

Noncompliant Code Example

With the default threshold of 3:

public void run() {
  prepare("action1");                              // Noncompliant - "action1" is duplicated 3 times
  execute("action1");
  release("action1");
}

@SuppressWarning("all")                            // Compliant - annotations are excluded
private void method1() { /* ... */ }
@SuppressWarning("all")
private void method2() { /* ... */ }

public String method3(String a) {
  System.out.println("'" + a + "'");               // Compliant - literal "'" has less than 5 characters and is excluded
  return "";                                       // Compliant - literal "" has less than 5 characters and is excluded
}

Compliant Solution

private static final String ACTION_1 = "action1";  // Compliant

public void run() {
  prepare(ACTION_1);                               // Compliant
  execute(ACTION_1);
  release(ACTION_1);
}

Exceptions

To prevent generating some false-positives, literals having less than 5 characters are excluded.

Duplicated string literals make the process of refactoring error-prone, since you must be sure to update all occurrences.

On the other hand, constants can be referenced from many places, but only need to be updated in a single place.

Noncompliant Code Example

With the default threshold of 3:

public void run() {
  prepare("action1");                              // Noncompliant - "action1" is duplicated 3 times
  execute("action1");
  release("action1");
}

@SuppressWarning("all")                            // Compliant - annotations are excluded
private void method1() { /* ... */ }
@SuppressWarning("all")
private void method2() { /* ... */ }

public String method3(String a) {
  System.out.println("'" + a + "'");               // Compliant - literal "'" has less than 5 characters and is excluded
  return "";                                       // Compliant - literal "" has less than 5 characters and is excluded
}

Compliant Solution

private static final String ACTION_1 = "action1";  // Compliant

public void run() {
  prepare(ACTION_1);                               // Compliant
  execute(ACTION_1);
  release(ACTION_1);
}

Exceptions

To prevent generating some false-positives, literals having less than 5 characters are excluded.

Returning null instead of an actual array or collection forces callers of the method to explicitly test for nullity, making them more complex and less readable.

Moreover, in many cases, null is used as a synonym for empty.

Noncompliant Code Example

public static List<Result> getResults() {
  return null;                             // Noncompliant
}

public static Result[] getResults() {
  return null;                             // Noncompliant
}

public static void main(String[] args) {
  Result[] results = getResults();

  if (results != null) {                   // Nullity test required to prevent NPE
    for (Result result: results) {
      /* ... */
    }
  }
}

Compliant Solution

public static List<Result> getResults() {
  return Collections.emptyList();          // Compliant
}

public static Result[] getResults() {
  return new Result[0];
}

public static void main(String[] args) {
  for (Result result: getResults()) {
    /* ... */
  }
}

See

• CERT, MSC19-C. - For functions that return an array, prefer returning an empty array over a null value
• CERT, MET55-J. - Return an empty array or collection instead of a null value for methods that return an array or collection

Returning null instead of an actual array or collection forces callers of the method to explicitly test for nullity, making them more complex and less readable.

Moreover, in many cases, null is used as a synonym for empty.

Noncompliant Code Example

public static List<Result> getResults() {
  return null;                             // Noncompliant
}

public static Result[] getResults() {
  return null;                             // Noncompliant
}

public static void main(String[] args) {
  Result[] results = getResults();

  if (results != null) {                   // Nullity test required to prevent NPE
    for (Result result: results) {
      /* ... */
    }
  }
}

Compliant Solution

public static List<Result> getResults() {
  return Collections.emptyList();          // Compliant
}

public static Result[] getResults() {
  return new Result[0];
}

public static void main(String[] args) {
  for (Result result: getResults()) {
    /* ... */
  }
}

See

• CERT, MSC19-C. - For functions that return an array, prefer returning an empty array over a null value
• CERT, MET55-J. - Return an empty array or collection instead of a null value for methods that return an array or collection

When logging a message there are several important requirements which must be fulfilled:

• The user must be able to easily retrieve the logs
• The format of all logged message must be uniform to allow the user to easily read the log
• Logged data must actually be recorded
• Sensitive data must only be logged securely

If a program directly writes to the standard outputs, there is absolutely no way to comply with those requirements. That's why defining and using a dedicated logger is highly recommended.

Noncompliant Code Example

System.out.println("My Message");  // Noncompliant

Compliant Solution

logger.log("My Message");

See

• CERT, ERR02-J. - Prevent exceptions while logging data

Duplicated Code

Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:

Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.

When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).

Tuning

This issue has a mass of 66.

We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.

The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.

If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.

See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.

Refactorings

• Extract Method
• Extract Class
• Form Template Method
• Introduce Null Object
• Pull Up Method
• Pull Up Field
• Substitute Algorithm

Further Reading

• Don't Repeat Yourself on the C2 Wiki
• Duplicated Code on SourceMaking
• Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76

Duplicated Code

Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:

Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.

When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).

Tuning

This issue has a mass of 66.

We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.

The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.

If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.

See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.

Refactorings

• Extract Method
• Extract Class
• Form Template Method
• Introduce Null Object
• Pull Up Method
• Pull Up Field
• Substitute Algorithm

Further Reading

• Don't Repeat Yourself on the C2 Wiki
• Duplicated Code on SourceMaking
• Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76