85 lines
1.8 KiB
Plaintext
85 lines
1.8 KiB
Plaintext
``++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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include::message.adoc[]
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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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