16f6c0aecf
Inline adoc files when they are included exactly once. Also fix language tags because this inlining gives us better information on what language the code is written in.
74 lines
1.8 KiB
Plaintext
74 lines
1.8 KiB
Plaintext
== Why is this an issue?
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It's a common pattern to test the result of a ``++java.util.Map.get()++`` against ``++null++`` or calling ``++java.util.Map.containsKey()++`` before proceeding with adding or changing the value in the map. However the ``++java.util.Map++`` API offers a significantly better alternative in the form of the ``++computeIfPresent()++`` and ``++computeIfAbsent()++`` methods. Using these instead leads to cleaner and more readable code.
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*Note* that this rule is automatically disabled when the project's ``++sonar.java.source++`` is not 8.
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=== Noncompliant code example
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[source,java]
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----
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V value = map.get(key);
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if (value == null) { // Noncompliant
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value = V.createFor(key);
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if (value != null) {
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map.put(key, value);
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}
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}
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if (!map.containsKey(key)) { // Noncompliant
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value = V.createFor(key);
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if (value != null) {
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map.put(key, value);
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}
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}
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return value;
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----
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=== Compliant solution
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[source,java]
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----
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return map.computeIfAbsent(key, k -> V.createFor(k));
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----
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=== Exceptions
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This rule will not raise an issue when trying to add ``++null++`` to a map, because ``++computeIfAbsent++`` will not add the entry if the value returned by the function is ``++null++``.
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== Resources
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=== Related rules
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* S6104 - Map "computeIfAbsent()" and "computeIfPresent()" should not be used to add "null" values.
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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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Replace this ("Map.get()" and condition | "Map.containsKey()") with a call to ("Map.computeIfAbsent()" | "Map.computeIfPresent()").
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=== Highlighting
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Primary: condition
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Secondary: ``++Map.get++`` call or ``++Map.containsKey++`` call
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'''
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== Comments And Links
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(visible only on this page)
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=== is related to: S6104
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endif::env-github,rspecator-view[]
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