60187a8f6f
* Revert "Modify rules S2259;S2583;S2589;S3518;S3655;S3959 Remove replacement rules and update description for deprecated SE rules (#4207)" This reverts commit d4d145e532aa487392b1e273e205854f68eb1328. * Revert "SONARJAVA-5102 Deprecate Java SE rules implemented by DBD (#4177)" This reverts commit 952c1cab7b996d1a3e5060bc91745df6543d7eaf.
91 lines
1.9 KiB
Plaintext
91 lines
1.9 KiB
Plaintext
== Why is this an issue?
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``++Optional++`` value can hold either a value or not. The value held in the ``++Optional++`` can be accessed using the ``++get()++`` method, but it will throw a
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``++NoSuchElementException++`` if there is no value present. To avoid the exception, calling the ``++isPresent()++`` or ``++! isEmpty()++`` method should always be done before any call to ``++get()++``.
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Alternatively, note that other methods such as ``++orElse(...)++``, ``++orElseGet(...)++`` or ``++orElseThrow(...)++`` can be used to specify what to do with an empty ``++Optional++``.
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=== Noncompliant code example
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[source,java]
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----
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Optional<String> value = this.getOptionalValue();
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// ...
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String stringValue = value.get(); // Noncompliant
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----
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[source,java]
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----
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if (methodThatReturnsOptional().isEmpty()) {
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throw new NotFoundException();
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}
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String value = methodThatReturnsOptional().get(); // Noncompliant: indirect access, we consider that two consecutive calls can return different values.
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----
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=== Compliant solution
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[source,java]
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----
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this.getOptionalValue().ifPresent(stringValue ->
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// Do something with stringValue
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);
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----
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or
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[source,java]
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----
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Optional<String> value = this.getOptionalValue();
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// ...
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if (value.isPresent()) {
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String stringValue = value.get();
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}
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----
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or
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[source,java]
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----
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Optional<String> value = this.getOptionalValue();
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// ...
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String stringValue = value.orElse("default");
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----
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[source,java]
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----
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Optional<String> optional = methodThatReturnsOptional();
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if (optional.isEmpty()) {
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throw new NotFoundException();
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}
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String value = optional.get();
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----
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include::../see.adoc[]
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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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call "xxx.isPresent()" before accessing the value.
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'''
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== Comments And Links
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(visible only on this page)
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include::../comments-and-links.adoc[]
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endif::env-github,rspecator-view[]
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