Optional::__construct() - Code Metrics - Inspection of "Update doctrine/coding-standard requirement from ^..." - Ocramius/ocramius.util.Optional - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#43)

by Niklas

created 2020-06-14 18:52 UTC

Optional::__construct() A

↳ Parent: Project

Complexity

Conditions	1
Paths	1

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	2
CRAP Score	1

Importance

Changes

Metric	Value
dl	0
loc	3
c	0
b	0
f	0
ccs	2
cts	2
cp	1
rs	10
cc	1
nc	1
nop	0
crap	1

<?php
/*
 * Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 */

declare(strict_types=1);

namespace ocramius\util;

use Exception;
use ocramius\util\exception\NoSuchElementException;
use ocramius\util\exception\NullPointerException;
use Throwable;

use function sprintf;
use function strval;

/**
 * A container object which may or may not contain a non-null value.
 * If a value is present, {@code isPresent()} will return {@code true} and
 * {@code get()} will return the value.
 *
 * <p>Additional methods that depend on the presence or absence of a contained
 * value are provided, such as {@link #orElse(java.lang.Object) orElse()}
 * (return a default value if value not present) and
 * {@link #ifPresent(java.util.function.Consumer) ifPresent()} (execute a block
 * of code if the value is present).
 *
 * <p>This is a value-based class; use of identity-sensitive operations
 * (including reference equality ({@code ==}), identity hash code, or
 * synchronization) on instances of {@code Optional} may have unpredictable
 * results and should be avoided.
 *
 * @template T The type of the value residing in the Optional wrapper.
 */
final class Optional
{
    /**
     * Common instance for {@code empty()}.
     */
    private static ?self $EMPTY = null;


    /**
     * If non-null, the value; if null, indicates no value is present
     *
     * @psalm-var T
     * @var mixed
     */
    private $value;

    /**
     * Constructs an empty instance.
     *
     * @implNote Generally only one empty instance, {@link Optional#EMPTY},
     * should exist per VM.
     *
     * @psalm-return self<T>
     */
    private function __construct()
    {
    }

    /**
     * Returns an empty {@code Optional} instance.  No value is present for this
     * Optional.
     *
     * @return self an empty {@code Optional}
     *
     * @apiNote Though it may be tempting to do so, avoid testing if an object
     * is empty by comparing with {@code ==} against instances returned by
     * {@code Option.empty()}. There is no guarantee that it is a singleton.
     * Instead, use {@link #isPresent()}.
     */
    public static function newEmpty(): self
    {
        return self::$EMPTY ?: self::$EMPTY = new self();
    }

    /**
     * Returns an {@code Optional} with the specified present non-null value.
     *
     * @param mixed $value the value to be present, which must be non-null
     *
     * @return self an {@code Optional} with the value present
     * @psalm-return self<T>
     *
     * @throws NullPointerException If value is null.
     *
     * @psalm-template T
     * @psalm-param T $value
     * @phpcsSuppress SlevomatCodingStandard.TypeHints.TypeHintDeclaration
     */
    public static function of($value): self
    {
        if ($value === null) {
            throw new NullPointerException();
        }

        $self = new self();

        $self->value = $value;

        return $self;
    }

    /**
     * Returns an {@code Optional} describing the specified value, if non-null,
     * otherwise returns an empty {@code Optional}.
     *
     * @param mixed|null $value the possibly-null value to describe
     *
     * @return self an {@code Optional} with a present value if the specified value
     * is non-null, otherwise an empty {@code Optional}
     *
     * @psalm-template T
     * @psalm-param T|null $value
     * @phpcsSuppress SlevomatCodingStandard.TypeHints.TypeHintDeclaration
     */
    public static function ofNullable($value): self
    {
        return $value === null ? self::newEmpty() : self::of($value);
    }

    /**
     * If a value is present in this {@code Optional}, returns the value,
     * otherwise throws {@code NoSuchElementException}.
     *
     * @see Optional#isPresent()
     *
     * @return mixed the non-null value held by this {@code Optional}
     *
     * @throws NoSuchElementException If there is no value present.
     *
     * @psalm-return T
     * @phpcsSuppress SlevomatCodingStandard.TypeHints.TypeHintDeclaration
     */
    public function get()
    {
        if ($this->value === null) {
            throw new NoSuchElementException('No value present');
        }

        return $this->value;
    }

    /**
     * Return {@code true} if there is a value present, otherwise {@code false}.
     *
     * @return bool {@code true} if there is a value present, otherwise {@code false}
     */
    public function isPresent(): bool
    {
        return $this->value !== null;
    }

    /**
     * If a value is present, invoke the specified consumer with the value,
     * otherwise do nothing.
     *
     * @param callable $consumer block to be executed if a value is present
     *
     * @psalm-param callable(T):void $consumer
     */
    public function ifPresent(callable $consumer): void
    {
        if ($this->value === null) {
            return;
        }

        $consumer($this->value);
    }

    /**
     * If a value is present, and the value matches the given predicate,
     * return an {@code Optional} describing the value, otherwise return an
     * empty {@code Optional}.
     *
     * @param callable $predicate a predicate to apply to the value, if present
     *
     * @return self an {@code Optional} describing the value of this {@code Optional}
     * if a value is present and the value matches the given predicate,
     * otherwise an empty {@code Optional}
     *
     * @throws NullPointerException If the predicate is null.
     *
     * @psalm-param callable(T):self $predicate
     */
    public function filter(callable $predicate): self
    {
        if ($this->value === null) {
            return $this;
        }

        return $predicate($this->value) ? $this : self::newEmpty();
    }

    /**
     * If a value is present, apply the provided mapping function to it,
     * and if the result is non-null, return an {@code Optional} describing the
     * result.  Otherwise return an empty {@code Optional}.
     *
     * @param callable $mapper a mapping function to apply to the value, if present
     *
     * @return self an {@code Optional} describing the result of applying a mapping
     * function to the value of this {@code Optional}, if a value is present,
     * otherwise an empty {@code Optional}
     *
     * @throws NullPointerException If the mapping function is null.
     *
     * @psalm-param callable(T):U $mapper
     * @psalm-return self<U>
     * @apiNote This method supports post-processing on optional values, without
     * the need to explicitly check for a return status.  For example, the
     * following code traverses a stream of file names, selects one that has
     * not yet been processed, and then opens that file, returning an
     * {@code Optional<FileInputStream>}:
     *
     * <pre>{@code
     *     Optional<FileInputStream> fis =
     *         names.stream().filter(name -> !isProcessedYet(name))
     *                       .findFirst()
     *                       .map(name -> new FileInputStream(name));
     * }</pre>
     *
     * Here, {@code findFirst} returns an {@code Optional<String>}, and then
     * {@code map} returns an {@code Optional<FileInputStream>} for the desired
     * file if one exists.
     * @template U
     */
    public function map(callable $mapper): self
    {
        if ($this->value === null) {
            return self::newEmpty();
        }

        return self::ofNullable($mapper($this->value));
    }

    /**
     * If a value is present, apply the provided {@code Optional}-bearing
     * mapping function to it, return that result, otherwise return an empty
     * {@code Optional}.  This method is similar to {@link #map(Function)},
     * but the provided mapper is one whose result is already an {@code Optional},
     * and if invoked, {@code flatMap} does not wrap it with an additional
     * {@code Optional}.
     *
     * @param callable $mapper a mapping function to apply to the value, if present
     *           the mapping function
     *
     * @return self the result of applying an {@code Optional}-bearing mapping
     * function to the value of this {@code Optional}, if a value is present,
     * otherwise an empty {@code Optional}
     *
     * @throws NullPointerException If the mapping function is null or returns
     * a null result.
     *
     * @template U
     * @psalm-param callable(T):self<U> $mapper
     * @psalm-return self<U>
     * @phpcsSuppress SlevomatCodingStandard.TypeHints.TypeHintDeclaration
     */
    public function flatMap(callable $mapper): self
    {
        if ($this->value === null) {
            return self::newEmpty();
        }

        $result = $mapper($this->value);

        if ($result === null) {
            throw new NullPointerException();
        }

        return $result;
    }

    /**
     * Return the value if present, otherwise return {@code other}.
     *
     * @param mixed $other the value to be returned if there is no value present, may
     * be null
     *
     * @return mixed the value, if present, otherwise {@code other}
     *
     * @psalm-param T $other
     * @psalm-return T
     * @phpcsSuppress SlevomatCodingStandard.TypeHints.TypeHintDeclaration
     */
    public function orElse($other)
    {
        return $this->value ?? $other;
    }

    /**
     * Return the value if present, otherwise invoke {@code other} and return
     * the result of that invocation.
     *
     * @param callable $other a {@code Supplier} whose result is returned if no value
     * is present
     *
     * @return mixed the value if present otherwise the result of {@code other.get()}
     *
     * @throws NullPointerException If value is not present and {@code other} is
     * null.
     *
     * @psalm-param callable():T $other
     * @psalm-return T
     * @phpcsSuppress SlevomatCodingStandard.TypeHints.TypeHintDeclaration
     */
    public function orElseGet(callable $other)
    {
        return $this->value ?? $other();
    }

    /**
     * Return the contained value, if present, otherwise throw an exception
     * to be created by the provided supplier.
     *
     * @param callable $exceptionSupplier The supplier which will return the exception to
     * be thrown
     *
     * @return mixed the present value
     *
     * @throws Exception If there is no value present.
     * @throws NullPointerException If no value is present and
     * {@code exceptionSupplier} is null.
     *
     * @psalm-param callable(): Throwable $exceptionSupplier
     * @psalm-return T
     * @apiNote A method reference to the exception constructor with an empty
     * argument list can be used as the supplier. For example,
     * {@code IllegalStateException::new}
     * @phpcsSuppress SlevomatCodingStandard.TypeHints.TypeHintDeclaration
     */
    public function orElseThrow(callable $exceptionSupplier)
    {
        if ($this->value === null) {
            throw $exceptionSupplier();
        }

        return $this->value;
    }

    /**
     * Indicates whether some other object is "equal to" this Optional. The
     * other object is considered equal if:
     * <ul>
     * <li>it is also an {@code Optional} and;
     * <li>both instances have no value present or;
     * <li>the present values are "equal to" each other via {@code equals()}.
     * </ul>
     *
     * @param mixed $object an object to be tested for equality
     *
     * @return bool {code true} if the other object is "equal to" this object
     * otherwise {@code false}
     */
    public function equals($object): bool
    {
        return $object === $this || ($object instanceof self && $object->value === $this->value);
    }

    /**
     * Returns a non-empty string representation of this Optional suitable for
     * debugging. The exact presentation format is unspecified and may vary
     * between implementations and versions.
     *
     * @return string the string representation of this instance
     *
     * @implSpec If a value is present the result must include its string
     * representation in the result. Empty and present Optionals must be
     * unambiguously differentiable.
     */
    public function __toString(): string
    {
        return $this->value === null ? 'Optional.empty' : sprintf('Optional[%s]', strval($this->value));
    }
}


1		<?php
2		/*
3		* Oracle designates this
4		* particular file as subject to the "Classpath" exception as provided
5		* by Oracle in the LICENSE file that accompanied this code.
6		*/
7
8		declare(strict_types=1);
9
10		namespace ocramius\util;
11
12		use Exception;
13		use ocramius\util\exception\NoSuchElementException;
14		use ocramius\util\exception\NullPointerException;
15		use Throwable;
16
17		use function sprintf;
18		use function strval;
19
20		/**
21		* A container object which may or may not contain a non-null value.
22		* If a value is present, {@code isPresent()} will return {@code true} and
23		* {@code get()} will return the value.
24		*
25		* <p>Additional methods that depend on the presence or absence of a contained
26		* value are provided, such as {@link #orElse(java.lang.Object) orElse()}
27		* (return a default value if value not present) and
28		* {@link #ifPresent(java.util.function.Consumer) ifPresent()} (execute a block
29		* of code if the value is present).
30		*
31		* <p>This is a value-based class; use of identity-sensitive operations
32		* (including reference equality ({@code ==}), identity hash code, or
33		* synchronization) on instances of {@code Optional} may have unpredictable
34		* results and should be avoided.
35		*
36		* @template T The type of the value residing in the Optional wrapper.
37		*/
38		final class Optional
39		{
40		/**
41		* Common instance for {@code empty()}.
42		*/
43		private static ?self $EMPTY = null;
		0 ignored issues – show Bug introduced 2020-06-14 18:58 UTC by Report Bug Copy Issue Report This code did not parse for me. Apparently, there is an error somewhere around this line: Syntax error, unexpected '?', expecting T_FUNCTION or T_CONST Loading history...
44
45		/**
46		* If non-null, the value; if null, indicates no value is present
47		*
48		* @psalm-var T
49		* @var mixed
50		*/
51		private $value;
52
53		/**
54		* Constructs an empty instance.
55		*
56		* @implNote Generally only one empty instance, {@link Optional#EMPTY},
57		* should exist per VM.
58		*
59	101	* @psalm-return self<T>
60		*/
61	101	private function __construct()
62		{
63		}
64
65		/**
66		* Returns an empty {@code Optional} instance. No value is present for this
67		* Optional.
68		*
69		* @return self an empty {@code Optional}
70		*
71		* @apiNote Though it may be tempting to do so, avoid testing if an object
72		* is empty by comparing with {@code ==} against instances returned by
73		* {@code Option.empty()}. There is no guarantee that it is a singleton.
74	68	* Instead, use {@link #isPresent()}.
75		*/
76	68	public static function newEmpty(): self
77		{
78		return self::$EMPTY ?: self::$EMPTY = new self();
79		}
80
81		/**
82		* Returns an {@code Optional} with the specified present non-null value.
83		*
84		* @param mixed $value the value to be present, which must be non-null
85		*
86		* @return self an {@code Optional} with the value present
87		* @psalm-return self<T>
88		*
89		* @throws NullPointerException If value is null.
90		*
91	101	* @psalm-template T
92		* @psalm-param T $value
93	101	* @phpcsSuppress SlevomatCodingStandard.TypeHints.TypeHintDeclaration
94	1	*/
95		public static function of($value): self
96		{
97	100	if ($value === null) {
98		throw new NullPointerException();
99	100	}
100
101	100	$self = new self();
102
103		$self->value = $value;
104
105		return $self;
106		}
107
108		/**
109		* Returns an {@code Optional} describing the specified value, if non-null,
110		* otherwise returns an empty {@code Optional}.
111		*
112		* @param mixed\|null $value the possibly-null value to describe
113		*
114		* @return self an {@code Optional} with a present value if the specified value
115		* is non-null, otherwise an empty {@code Optional}
116	18	*
117		* @psalm-template T
118	18	* @psalm-param T\|null $value
119		* @phpcsSuppress SlevomatCodingStandard.TypeHints.TypeHintDeclaration
120		*/
121		public static function ofNullable($value): self
122		{
123		return $value === null ? self::newEmpty() : self::of($value);
124		}
125
126		/**
127		* If a value is present in this {@code Optional}, returns the value,
128		* otherwise throws {@code NoSuchElementException}.
129		*
130		* @see Optional#isPresent()
131		*
132		* @return mixed the non-null value held by this {@code Optional}
133		*
134	25	* @throws NoSuchElementException If there is no value present.
135		*
136	25	* @psalm-return T
137	1	* @phpcsSuppress SlevomatCodingStandard.TypeHints.TypeHintDeclaration
138		*/
139		public function get()
140	24	{
141		if ($this->value === null) {
142		throw new NoSuchElementException('No value present');
143		}
144
145		return $this->value;
146		}
147
148	17	/**
149		* Return {@code true} if there is a value present, otherwise {@code false}.
150	17	*
151		* @return bool {@code true} if there is a value present, otherwise {@code false}
152		*/
153		public function isPresent(): bool
154		{
155		return $this->value !== null;
156		}
157
158		/**
159		* If a value is present, invoke the specified consumer with the value,
160		* otherwise do nothing.
161	9	*
162		* @param callable $consumer block to be executed if a value is present
163	9	*
164	1	* @psalm-param callable(T):void $consumer
165		*/
166		public function ifPresent(callable $consumer): void
167	8	{
168	8	if ($this->value === null) {
169		return;
170		}
171
172		$consumer($this->value);
173		}
174
175		/**
176		* If a value is present, and the value matches the given predicate,
177		* return an {@code Optional} describing the value, otherwise return an
178		* empty {@code Optional}.
179		*
180		* @param callable $predicate a predicate to apply to the value, if present
181		*
182		* @return self an {@code Optional} describing the value of this {@code Optional}
183		* if a value is present and the value matches the given predicate,
184		* otherwise an empty {@code Optional}
185	17	*
186		* @throws NullPointerException If the predicate is null.
187	17	*
188	1	* @psalm-param callable(T):self $predicate
189		*/
190		public function filter(callable $predicate): self
191	16	{
192		if ($this->value === null) {
193		return $this;
194		}
195
196		return $predicate($this->value) ? $this : self::newEmpty();
197		}
198
199		/**
200		* If a value is present, apply the provided mapping function to it,
201		* and if the result is non-null, return an {@code Optional} describing the
202		* result. Otherwise return an empty {@code Optional}.
203		*
204		* @param callable $mapper a mapping function to apply to the value, if present
205		*
206		* @return self an {@code Optional} describing the result of applying a mapping
207		* function to the value of this {@code Optional}, if a value is present,
208		* otherwise an empty {@code Optional}
209		*
210		* @throws NullPointerException If the mapping function is null.
211		*
212		* @psalm-param callable(T):U $mapper
213		* @psalm-return self<U>
214		* @apiNote This method supports post-processing on optional values, without
215		* the need to explicitly check for a return status. For example, the
216		* following code traverses a stream of file names, selects one that has
217		* not yet been processed, and then opens that file, returning an
218		* {@code Optional<FileInputStream>}:
219		*
220		* <pre>{@code
221		* Optional<FileInputStream> fis =
222		* names.stream().filter(name -> !isProcessedYet(name))
223		* .findFirst()
224		* .map(name -> new FileInputStream(name));
225		* }</pre>
226		*
227	10	* Here, {@code findFirst} returns an {@code Optional<String>}, and then
228		* {@code map} returns an {@code Optional<FileInputStream>} for the desired
229	10	* file if one exists.
230	1	* @template U
231		*/
232		public function map(callable $mapper): self
233	9	{
234		if ($this->value === null) {
235		return self::newEmpty();
236		}
237
238		return self::ofNullable($mapper($this->value));
239		}
240
241		/**
242		* If a value is present, apply the provided {@code Optional}-bearing
243		* mapping function to it, return that result, otherwise return an empty
244		* {@code Optional}. This method is similar to {@link #map(Function)},
245		* but the provided mapper is one whose result is already an {@code Optional},
246		* and if invoked, {@code flatMap} does not wrap it with an additional
247		* {@code Optional}.
248		*
249		* @param callable $mapper a mapping function to apply to the value, if present
250		* the mapping function
251		*
252		* @return self the result of applying an {@code Optional}-bearing mapping
253		* function to the value of this {@code Optional}, if a value is present,
254		* otherwise an empty {@code Optional}
255		*
256		* @throws NullPointerException If the mapping function is null or returns
257		* a null result.
258		*
259	10	* @template U
260		* @psalm-param callable(T):self<U> $mapper
261	10	* @psalm-return self<U>
262	1	* @phpcsSuppress SlevomatCodingStandard.TypeHints.TypeHintDeclaration
263		*/
264		public function flatMap(callable $mapper): self
265	9	{
266		if ($this->value === null) {
267	9	return self::newEmpty();
268	1	}
269
270		$result = $mapper($this->value);
271	8
272		if ($result === null) {
273		throw new NullPointerException();
274		}
275
276		return $result;
277		}
278
279		/**
280		* Return the value if present, otherwise return {@code other}.
281		*
282		* @param mixed $other the value to be returned if there is no value present, may
283		* be null
284		*
285		* @return mixed the value, if present, otherwise {@code other}
286	16	*
287		* @psalm-param T $other
288	16	* @psalm-return T
289		* @phpcsSuppress SlevomatCodingStandard.TypeHints.TypeHintDeclaration
290		*/
291		public function orElse($other)
292		{
293		return $this->value ?? $other;
294		}
295
296		/**
297		* Return the value if present, otherwise invoke {@code other} and return
298		* the result of that invocation.
299		*
300		* @param callable $other a {@code Supplier} whose result is returned if no value
301		* is present
302		*
303		* @return mixed the value if present otherwise the result of {@code other.get()}
304		*
305		* @throws NullPointerException If value is not present and {@code other} is
306		* null.
307	16	*
308		* @psalm-param callable():T $other
309	16	* @psalm-return T
310		* @phpcsSuppress SlevomatCodingStandard.TypeHints.TypeHintDeclaration
311		*/
312		public function orElseGet(callable $other)
313		{
314		return $this->value ?? $other();
315		}
316
317		/**
318		* Return the contained value, if present, otherwise throw an exception
319		* to be created by the provided supplier.
320		*
321		* @param callable $exceptionSupplier The supplier which will return the exception to
322		* be thrown
323		*
324		* @return mixed the present value
325		*
326		* @throws Exception If there is no value present.
327		* @throws NullPointerException If no value is present and
328		* {@code exceptionSupplier} is null.
329		*
330		* @psalm-param callable(): Throwable $exceptionSupplier
331		* @psalm-return T
332	9	* @apiNote A method reference to the exception constructor with an empty
333		* argument list can be used as the supplier. For example,
334	9	* {@code IllegalStateException::new}
335	1	* @phpcsSuppress SlevomatCodingStandard.TypeHints.TypeHintDeclaration
336		*/
337		public function orElseThrow(callable $exceptionSupplier)
338	8	{
339		if ($this->value === null) {
340		throw $exceptionSupplier();
341		}
342
343		return $this->value;
344		}
345
346		/**
347		* Indicates whether some other object is "equal to" this Optional. The
348		* other object is considered equal if:
349		* <ul>
350		* <li>it is also an {@code Optional} and;
351		* <li>both instances have no value present or;
352		* <li>the present values are "equal to" each other via {@code equals()}.
353		* </ul>
354		*
355	17	* @param mixed $object an object to be tested for equality
356		*
357	17	* @return bool {code true} if the other object is "equal to" this object
358		* otherwise {@code false}
359		*/
360		public function equals($object): bool
361		{
362		return $object === $this \|\| ($object instanceof self && $object->value === $this->value);
363		}
364
365		/**
366		* Returns a non-empty string representation of this Optional suitable for
367		* debugging. The exact presentation format is unspecified and may vary
368		* between implementations and versions.
369		*
370		* @return string the string representation of this instance
371	1	*
372		* @implSpec If a value is present the result must include its string
373	1	* representation in the result. Empty and present Optionals must be
374		* unambiguously differentiable.
375		*/
376		public function __toString(): string
377		{
378		return $this->value === null ? 'Optional.empty' : sprintf('Optional[%s]', strval($this->value));
379		}
380		}
381

Ocramius / ocramius.util.Optional

Pull Request — master (#43)

Optional::__construct() A

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