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.
90 lines
1.9 KiB
Plaintext
90 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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