Showing 16 of 16 total issues
Method getPacket
has a Cognitive Complexity of 19 (exceeds 5 allowed). Consider refactoring. Open
public static Packet getPacket(int state, Direction direction, ByteReader reader, int id) {
if (state == 0) {
if (direction == Direction.SERVERBOUND) {
if (id == 0x00) {
return new HandshakePacket(reader);
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Cognitive Complexity
Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.
A method's cognitive complexity is based on a few simple rules:
- Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
- Code is considered more complex for each "break in the linear flow of the code"
- Code is considered more complex when "flow breaking structures are nested"
Further reading
Method handlePacket
has a Cognitive Complexity of 10 (exceeds 5 allowed). Consider refactoring. Open
private void handlePacket(Packet packet) {
if (state == 0) {
if (packet.getId() == 0x00) { // handshake packet
HandshakePacket handshakePacket = (HandshakePacket) packet;
this.state = handshakePacket.getNextState();
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Cognitive Complexity
Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.
A method's cognitive complexity is based on a few simple rules:
- Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
- Code is considered more complex for each "break in the linear flow of the code"
- Code is considered more complex when "flow breaking structures are nested"
Further reading
Identical blocks of code found in 2 locations. Consider refactoring. Open
while (((data = bytes[iterations]) & 0x80) != 0) {
int realValue = data & 0x75 << iterations * 7;
value |= realValue;
iterations++;
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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 62.
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
Identical blocks of code found in 2 locations. Consider refactoring. Open
while (((data = in.readByte()) & 0x80) != 0) { // check if MSB is set. When this equals 0 we have reached the last byte
int realValue = data & 0x75 << iterations * 7; // This sets the MSB to 0 and shifts by the number of bits we've read (number of bits read = iterations * 7 bit (7 because we ignore MSB)).
value |= realValue; // OR the numbers so they overlay
iterations++;
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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 62.
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
Avoid too many return
statements within this method. Open
return null;
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Add a private constructor to hide the implicit public one. Open
public class DataUtil {
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Utility classes, which are collections of static
members, are not meant to be instantiated. Even abstract utility classes, which can
be extended, should not have public constructors.
Java adds an implicit public constructor to every class which does not define at least one explicitly. Hence, at least one non-public constructor should be defined.
Noncompliant Code Example
class StringUtils { // Noncompliant public static String concatenate(String s1, String s2) { return s1 + s2; } }
Compliant Solution
class StringUtils { // Compliant private StringUtils() { throw new IllegalStateException("Utility class"); } public static String concatenate(String s1, String s2) { return s1 + s2; } }
Exceptions
When class contains public static void main(String[] args)
method it is not considered as utility class and will be ignored by this
rule.
Refactor this method to reduce its Cognitive Complexity from 17 to the 15 allowed. Open
public MCServer() throws IOException {
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Cognitive Complexity is a measure of how hard the control flow of a method is to understand. Methods with high Cognitive Complexity will be difficult to maintain.
See
Merge this if statement with the enclosing one. Open
if (id == 0x00) {
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Merging collapsible if
statements increases the code's readability.
Noncompliant Code Example
if (file != null) { if (file.isFile() || file.isDirectory()) { /* ... */ } }
Compliant Solution
if (file != null && isFileOrDirectory(file)) { /* ... */ } private static boolean isFileOrDirectory(File file) { return file.isFile() || file.isDirectory(); }
Refactor this method to reduce its Cognitive Complexity from 19 to the 15 allowed. Open
public static Packet getPacket(int state, Direction direction, ByteReader reader, int id) {
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Cognitive Complexity is a measure of how hard the control flow of a method is to understand. Methods with high Cognitive Complexity will be difficult to maintain.
See
Define a constant instead of duplicating this literal "Too many bits received while reading unsigned var int" 3 times. Open
MCServer.getMCServer().error("Too many bits received while reading unsigned var int");
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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.
Remove this assignment of "instance". Open
instance = this;
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Assigning a value to a static
field in a constructor could cause unreliable behavior at runtime since it will change the value for all
instances of the class.
Instead remove the field's static
modifier, or initialize it statically.
Noncompliant Code Example
public class Person { static Date dateOfBirth; static int expectedFingers; public Person(date birthday) { dateOfBirth = birthday; // Noncompliant; now everyone has this birthday expectedFingers = 10; // Noncompliant } }
Compliant Solution
public class Person { Date dateOfBirth; static int expectedFingers = 10; public Person(date birthday) { dateOfBirth = birthday; } }
Merge this if statement with the enclosing one. Open
if (id == 0x00) {
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- Exclude checks
Merging collapsible if
statements increases the code's readability.
Noncompliant Code Example
if (file != null) { if (file.isFile() || file.isDirectory()) { /* ... */ } }
Compliant Solution
if (file != null && isFileOrDirectory(file)) { /* ... */ } private static boolean isFileOrDirectory(File file) { return file.isFile() || file.isDirectory(); }
Define a constant instead of duplicating this literal "Reader had too few bytes" 3 times. Open
throw new IllegalArgumentException("Reader had too few bytes");
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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.
Merge this if statement with the enclosing one. Open
if (packet.getId() == 0x00) {
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Merging collapsible if
statements increases the code's readability.
Noncompliant Code Example
if (file != null) { if (file.isFile() || file.isDirectory()) { /* ... */ } }
Compliant Solution
if (file != null && isFileOrDirectory(file)) { /* ... */ } private static boolean isFileOrDirectory(File file) { return file.isFile() || file.isDirectory(); }
Merge this if statement with the enclosing one. Open
if (direction == Direction.SERVERBOUND) {
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Merging collapsible if
statements increases the code's readability.
Noncompliant Code Example
if (file != null) { if (file.isFile() || file.isDirectory()) { /* ... */ } }
Compliant Solution
if (file != null && isFileOrDirectory(file)) { /* ... */ } private static boolean isFileOrDirectory(File file) { return file.isFile() || file.isDirectory(); }
Remove this expression which always evaluates to "true" Open
while (scanner.hasNext() && run) {
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If a boolean expression doesn't change the evaluation of the condition, then it is entirely unnecessary, and can be removed. If it is gratuitous because it does not match the programmer's intent, then it's a bug and the expression should be fixed.
Noncompliant Code Example
a = true; if (a) { // Noncompliant doSomething(); } if (b && a) { // Noncompliant; "a" is always "true" doSomething(); } if (c || !a) { // Noncompliant; "!a" is always "false" doSomething(); }
Compliant Solution
a = true; if (foo(a)) { doSomething(); } if (b) { doSomething(); } if (c) { doSomething(); }
See
- MITRE, CWE-571 - Expression is Always True
- MITRE, CWE-570 - Expression is Always False