417d2d9651
Co-authored-by: Dorian Burihabwa <75226315+dorian-burihabwa-sonarsource@users.noreply.github.com>
87 lines
2.8 KiB
Plaintext
87 lines
2.8 KiB
Plaintext
== Why is this an issue?
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Using boxed values in a ternary operator does not simply return one operand or the other based on the condition.
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Instead, the values are unboxed and coerced to a common type, which can result in a loss of precision when converting one operand from `int` to `float` or from `long` to `double`.
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While this behavior is expected for arithmetic operations, it may be unexpected for the ternary operator.
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To avoid confusion or unexpected behavior, cast to a compatible type explicitly.
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== How to fix it
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=== Code examples
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==== Noncompliant code example
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Cast one of both operands to a common supertype (e.g., `Number`) to prevent auto-unboxing and, thus, type coercion.
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[source,java,diff-id=1,diff-type=noncompliant]
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----
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Integer i = 123456789;
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Float f = 1.0f;
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Number n1 = condition ? i : f; // Noncompliant, unexpected precision loss, n1 = 1.23456792E8
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----
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==== Compliant solution
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[source,java,diff-id=1,diff-type=compliant]
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----
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Integer i = 123456789;
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Float f = 1.0f;
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Number n1 = condition ? (Number) i : f; // Compliant, cast to Number prevents unboxing
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Number n2 = condition ? i : (Number) f; // Compliant, cast to Number prevents unboxing
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----
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==== Noncompliant code example
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If type coercion was your intention, clarify this by casting the operand that would be coerced to the corresponding type explicitly.
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[source,java,diff-id=2,diff-type=noncompliant]
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----
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Integer i = 123456789;
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Float f = 1.0f;
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Number n1 = condition ? i : f; // Noncompliant, unexpected precision loss, n1 = 1.23456792E8
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----
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==== Compliant solution
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[source,java,diff-id=2,diff-type=compliant]
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----
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Integer i = 123456789;
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Float f = 1.0f;
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Number n = condition ? (float) i : f; // Compliant, intentional type coercion with precision loss
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----
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== Resources
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=== Documentation
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* https://docs.oracle.com/javase/tutorial/java/nutsandbolts/op2.html[The Java Tutorials: Equality, Relational, and Conditional Operators]
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* https://docs.oracle.com/javase/tutorial/java/data/autoboxing.html[The Java Tutorials: Autoboxing and Unboxing]
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* https://docs.oracle.com/javase/specs/jls/se7/html/jls-5.html[The Java® Language Specification Java SE 7 Edition: Chapter 5. Conversions and Promotions]
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=== Articles & blog posts
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* https://www.geeksforgeeks.org/coercion-in-java/[GeeksforGeeks: Coercion in Java]
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ifdef::env-github,rspecator-view[]
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'''
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== Implementation Specification
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(visible only on this page)
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=== Message
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Add an explicit cast to match types of operands.
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'''
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== Comments And Links
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(visible only on this page)
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=== on 16 Feb 2015, 18:02:37 Michael Gumowski wrote:
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Message changed, as the type of the ternary operation can not be resolved at the moment. Indicating the required cast is not yet possible.
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Moreover, other expressions than variables can be used as operand.
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endif::env-github,rspecator-view[]
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