From 5459113b816f4b1e15d30dffdc1d0e85bdaf4585 Mon Sep 17 00:00:00 2001
From: Massimiliano Arione <garakkio@gmail.com>
Date: Thu, 12 Sep 2019 15:47:49 +0200
Subject: [PATCH] add typehints and return types

---
 src/BinaryUtils.php                        |  6 +-
 src/Builder/DefaultUuidBuilder.php         |  3 +-
 src/Builder/DegradedUuidBuilder.php        |  3 +-
 src/Builder/UuidBuilderInterface.php       |  2 +-
 src/Codec/CodecInterface.php               |  8 +-
 src/Codec/GuidStringCodec.php              |  8 +-
 src/Codec/OrderedTimeCodec.php             |  4 +-
 src/Codec/StringCodec.php                  |  8 +-
 src/Codec/TimestampFirstCombCodec.php      |  8 +-
 src/DegradedUuid.php                       | 11 +--
 src/FeatureSet.php                         | 36 ++++-----
 src/Generator/CombGenerator.php            |  8 +-
 src/Generator/DefaultTimeGenerator.php     | 17 +++--
 src/Generator/PeclUuidRandomGenerator.php  |  4 +-
 src/Generator/PeclUuidTimeGenerator.php    |  2 +-
 src/Generator/RandomBytesGenerator.php     |  4 +-
 src/Generator/RandomGeneratorFactory.php   |  2 +-
 src/Generator/RandomGeneratorInterface.php |  6 +-
 src/Generator/RandomLibAdapter.php         |  6 +-
 src/Generator/TimeGeneratorFactory.php     |  2 +-
 src/Generator/TimeGeneratorInterface.php   |  2 +-
 src/Provider/Node/FallbackNodeProvider.php |  2 +-
 src/Provider/Node/RandomNodeProvider.php   |  2 +-
 src/Provider/Node/SystemNodeProvider.php   |  4 +-
 src/Provider/NodeProviderInterface.php     |  2 +-
 src/Provider/Time/FixedTimeProvider.php    |  6 +-
 src/Provider/Time/SystemTimeProvider.php   |  2 +-
 src/Provider/TimeProviderInterface.php     |  2 +-
 src/Uuid.php                               | 85 +++++++++++-----------
 src/UuidFactory.php                        | 39 +++++-----
 src/UuidFactoryInterface.php               | 16 ++--
 src/UuidInterface.php                      | 46 ++++++------
 src/Validator/Validator.php                |  2 +-
 src/Validator/ValidatorInterface.php       |  2 +-
 34 files changed, 185 insertions(+), 175 deletions(-)

diff --git a/src/BinaryUtils.php b/src/BinaryUtils.php
index c27daa6..2b223b1 100644
--- a/src/BinaryUtils.php
+++ b/src/BinaryUtils.php
@@ -14,7 +14,7 @@ class BinaryUtils
      * @return int The high field of the clock sequence multiplexed with the variant
      * @link http://tools.ietf.org/html/rfc4122#section-4.1.1
      */
-    public static function applyVariant($clockSeqHi)
+    public static function applyVariant($clockSeqHi): int
     {
         // Set the variant to RFC 4122
         $clockSeqHi = $clockSeqHi & 0x3f;
@@ -27,11 +27,11 @@ class BinaryUtils
      * Applies the RFC 4122 version number to the `time_hi_and_version` field
      *
      * @param string $timeHi
-     * @param integer $version
+     * @param int $version
      * @return int The high field of the timestamp multiplexed with the version number
      * @link http://tools.ietf.org/html/rfc4122#section-4.1.3
      */
-    public static function applyVersion($timeHi, $version)
+    public static function applyVersion(string $timeHi, int $version): int
     {
         $timeHi = hexdec($timeHi) & 0x0fff;
         $timeHi |= $version << 12;
diff --git a/src/Builder/DefaultUuidBuilder.php b/src/Builder/DefaultUuidBuilder.php
index 84f4505..0721fc4 100644
--- a/src/Builder/DefaultUuidBuilder.php
+++ b/src/Builder/DefaultUuidBuilder.php
@@ -18,6 +18,7 @@ use Ramsey\Uuid\Codec\CodecInterface;
 use Ramsey\Uuid\Converter\NumberConverterInterface;
 use Ramsey\Uuid\Converter\TimeConverterInterface;
 use Ramsey\Uuid\Uuid;
+use Ramsey\Uuid\UuidInterface;
 
 /**
  * DefaultUuidBuilder is the default UUID builder for ramsey/uuid; it builds
@@ -57,7 +58,7 @@ class DefaultUuidBuilder implements UuidBuilderInterface
      *     see {@see \Ramsey\Uuid\UuidInterface::getFieldsHex()} for array structure.
      * @return Uuid
      */
-    public function build(CodecInterface $codec, array $fields)
+    public function build(CodecInterface $codec, array $fields): UuidInterface
     {
         return new Uuid($fields, $this->numberConverter, $codec, $this->timeConverter);
     }
diff --git a/src/Builder/DegradedUuidBuilder.php b/src/Builder/DegradedUuidBuilder.php
index 5a94aa3..947d267 100644
--- a/src/Builder/DegradedUuidBuilder.php
+++ b/src/Builder/DegradedUuidBuilder.php
@@ -18,6 +18,7 @@ use Ramsey\Uuid\Codec\CodecInterface;
 use Ramsey\Uuid\Converter\NumberConverterInterface;
 use Ramsey\Uuid\Converter\TimeConverterInterface;
 use Ramsey\Uuid\DegradedUuid;
+use Ramsey\Uuid\UuidInterface;
 
 /**
  * DegradedUuidBuilder builds instances of DegradedUuid
@@ -56,7 +57,7 @@ class DegradedUuidBuilder implements UuidBuilderInterface
      *     see {@see \Ramsey\Uuid\UuidInterface::getFieldsHex()} for array structure.
      * @return DegradedUuid
      */
-    public function build(CodecInterface $codec, array $fields)
+    public function build(CodecInterface $codec, array $fields): UuidInterface
     {
         return new DegradedUuid($fields, $this->numberConverter, $codec, $this->timeConverter);
     }
diff --git a/src/Builder/UuidBuilderInterface.php b/src/Builder/UuidBuilderInterface.php
index e4e9901..22457b4 100644
--- a/src/Builder/UuidBuilderInterface.php
+++ b/src/Builder/UuidBuilderInterface.php
@@ -30,5 +30,5 @@ interface UuidBuilderInterface
      *     see {@see \Ramsey\Uuid\UuidInterface::getFieldsHex()} for array structure.
      * @return UuidInterface
      */
-    public function build(CodecInterface $codec, array $fields);
+    public function build(CodecInterface $codec, array $fields): UuidInterface;
 }
diff --git a/src/Codec/CodecInterface.php b/src/Codec/CodecInterface.php
index c6c54c7..8b34ac6 100644
--- a/src/Codec/CodecInterface.php
+++ b/src/Codec/CodecInterface.php
@@ -29,7 +29,7 @@ interface CodecInterface
      * @param UuidInterface $uuid
      * @return string Hexadecimal string representation of a UUID
      */
-    public function encode(UuidInterface $uuid);
+    public function encode(UuidInterface $uuid): string;
 
     /**
      * Encodes a UuidInterface as a binary representation of a UUID
@@ -37,7 +37,7 @@ interface CodecInterface
      * @param UuidInterface $uuid
      * @return string Binary string representation of a UUID
      */
-    public function encodeBinary(UuidInterface $uuid);
+    public function encodeBinary(UuidInterface $uuid): string;
 
     /**
      * Decodes a string representation of a UUID into a UuidInterface object instance
@@ -46,7 +46,7 @@ interface CodecInterface
      * @return UuidInterface
      * @throws InvalidUuidStringException
      */
-    public function decode($encodedUuid);
+    public function decode(string $encodedUuid): UuidInterface;
 
     /**
      * Decodes a binary representation of a UUID into a UuidInterface object instance
@@ -56,5 +56,5 @@ interface CodecInterface
      * @throws InvalidUuidStringException
      * @throws InvalidArgumentException if string has not 16 characters
      */
-    public function decodeBytes($bytes);
+    public function decodeBytes(string $bytes): UuidInterface;
 }
diff --git a/src/Codec/GuidStringCodec.php b/src/Codec/GuidStringCodec.php
index a4c1d77..24b434a 100644
--- a/src/Codec/GuidStringCodec.php
+++ b/src/Codec/GuidStringCodec.php
@@ -30,7 +30,7 @@ class GuidStringCodec extends StringCodec
      * @param UuidInterface $uuid
      * @return string Hexadecimal string representation of a GUID
      */
-    public function encode(UuidInterface $uuid)
+    public function encode(UuidInterface $uuid): string
     {
         $components = array_values($uuid->getFieldsHex());
 
@@ -49,7 +49,7 @@ class GuidStringCodec extends StringCodec
      * @param UuidInterface $uuid
      * @return string Binary string representation of a GUID
      */
-    public function encodeBinary(UuidInterface $uuid)
+    public function encodeBinary(UuidInterface $uuid): string
     {
         $components = array_values($uuid->getFieldsHex());
 
@@ -63,7 +63,7 @@ class GuidStringCodec extends StringCodec
      * @return UuidInterface
      * @throws InvalidUuidStringException
      */
-    public function decode($encodedUuid)
+    public function decode(string $encodedUuid): UuidInterface
     {
         $components = $this->extractComponents($encodedUuid);
 
@@ -79,7 +79,7 @@ class GuidStringCodec extends StringCodec
      * @return UuidInterface
      * @throws InvalidUuidStringException
      */
-    public function decodeBytes($bytes)
+    public function decodeBytes(string $bytes): UuidInterface
     {
         // Specifically call parent::decode to preserve correct byte order
         return parent::decode(bin2hex($bytes));
diff --git a/src/Codec/OrderedTimeCodec.php b/src/Codec/OrderedTimeCodec.php
index 7f05d64..e39416a 100644
--- a/src/Codec/OrderedTimeCodec.php
+++ b/src/Codec/OrderedTimeCodec.php
@@ -29,7 +29,7 @@ class OrderedTimeCodec extends StringCodec
      * @param UuidInterface $uuid
      * @return string Binary string representation of a UUID
      */
-    public function encodeBinary(UuidInterface $uuid)
+    public function encodeBinary(UuidInterface $uuid): string
     {
         $fields = $uuid->getFieldsHex();
 
@@ -52,7 +52,7 @@ class OrderedTimeCodec extends StringCodec
      * @return UuidInterface
      * @throws InvalidArgumentException if string has not 16 characters
      */
-    public function decodeBytes($bytes)
+    public function decodeBytes(string $bytes): UuidInterface
     {
         if (strlen($bytes) !== 16) {
             throw new InvalidArgumentException('$bytes string should contain 16 characters.');
diff --git a/src/Codec/StringCodec.php b/src/Codec/StringCodec.php
index 1735088..738ceb2 100644
--- a/src/Codec/StringCodec.php
+++ b/src/Codec/StringCodec.php
@@ -48,7 +48,7 @@ class StringCodec implements CodecInterface
      * @param UuidInterface $uuid
      * @return string Hexadecimal string representation of a UUID
      */
-    public function encode(UuidInterface $uuid)
+    public function encode(UuidInterface $uuid): string
     {
         $fields = array_values($uuid->getFieldsHex());
 
@@ -64,7 +64,7 @@ class StringCodec implements CodecInterface
      * @param UuidInterface $uuid
      * @return string Binary string representation of a UUID
      */
-    public function encodeBinary(UuidInterface $uuid)
+    public function encodeBinary(UuidInterface $uuid): string
     {
         return (string) hex2bin($uuid->getHex());
     }
@@ -76,7 +76,7 @@ class StringCodec implements CodecInterface
      * @return UuidInterface
      * @throws InvalidUuidStringException
      */
-    public function decode($encodedUuid)
+    public function decode(string $encodedUuid): UuidInterface
     {
         $components = $this->extractComponents($encodedUuid);
         $fields = $this->getFields($components);
@@ -91,7 +91,7 @@ class StringCodec implements CodecInterface
      * @return UuidInterface
      * @throws InvalidArgumentException if string has not 16 characters
      */
-    public function decodeBytes($bytes)
+    public function decodeBytes(string $bytes): UuidInterface
     {
         if (strlen($bytes) !== 16) {
             throw new InvalidArgumentException('$bytes string should contain 16 characters.');
diff --git a/src/Codec/TimestampFirstCombCodec.php b/src/Codec/TimestampFirstCombCodec.php
index a630369..006c3bc 100644
--- a/src/Codec/TimestampFirstCombCodec.php
+++ b/src/Codec/TimestampFirstCombCodec.php
@@ -29,7 +29,7 @@ class TimestampFirstCombCodec extends StringCodec
      *
      * @return string Hexadecimal string representation of a GUID
      */
-    public function encode(UuidInterface $uuid)
+    public function encode(UuidInterface $uuid): string
     {
         $sixPieceComponents = array_values($uuid->getFieldsHex());
 
@@ -48,7 +48,7 @@ class TimestampFirstCombCodec extends StringCodec
      *
      * @return string Binary string representation of timestamp first COMB UUID
      */
-    public function encodeBinary(UuidInterface $uuid)
+    public function encodeBinary(UuidInterface $uuid): string
     {
         $stringEncoding = $this->encode($uuid);
 
@@ -63,7 +63,7 @@ class TimestampFirstCombCodec extends StringCodec
      * @return UuidInterface
      * @throws InvalidUuidStringException
      */
-    public function decode($encodedUuid)
+    public function decode(string $encodedUuid): UuidInterface
     {
         $fivePieceComponents = $this->extractComponents($encodedUuid);
 
@@ -80,7 +80,7 @@ class TimestampFirstCombCodec extends StringCodec
      * @return UuidInterface
      * @throws InvalidUuidStringException
      */
-    public function decodeBytes($bytes)
+    public function decodeBytes(string $bytes): UuidInterface
     {
         return $this->decode(bin2hex($bytes));
     }
diff --git a/src/DegradedUuid.php b/src/DegradedUuid.php
index 388cd9f..c53154b 100644
--- a/src/DegradedUuid.php
+++ b/src/DegradedUuid.php
@@ -15,6 +15,7 @@
 namespace Ramsey\Uuid;
 
 use DateTimeImmutable;
+use DateTimeInterface;
 use Moontoast\Math\BigNumber;
 use Ramsey\Uuid\Exception\UnsatisfiedDependencyException;
 use Ramsey\Uuid\Exception\UnsupportedOperationException;
@@ -29,7 +30,7 @@ class DegradedUuid extends Uuid
     /**
      * @inheritdoc
      */
-    public function getDateTime()
+    public function getDateTime(): DateTimeInterface
     {
         if ($this->getVersion() != 1) {
             throw new UnsupportedOperationException('Not a time-based UUID');
@@ -48,7 +49,7 @@ class DegradedUuid extends Uuid
      * @return array
      * @throws UnsatisfiedDependencyException if called on a 32-bit system
      */
-    public function getFields()
+    public function getFields(): array
     {
         throw new UnsatisfiedDependencyException(
             'Cannot call ' . __METHOD__ . ' on a 32-bit system, since some '
@@ -64,7 +65,7 @@ class DegradedUuid extends Uuid
      * @return int
      * @throws UnsatisfiedDependencyException if called on a 32-bit system
      */
-    public function getNode()
+    public function getNode(): int
     {
         throw new UnsatisfiedDependencyException(
             'Cannot call ' . __METHOD__ . ' on a 32-bit system, since node '
@@ -81,7 +82,7 @@ class DegradedUuid extends Uuid
      * @return int
      * @throws UnsatisfiedDependencyException if called on a 32-bit system
      */
-    public function getTimeLow()
+    public function getTimeLow(): int
     {
         throw new UnsatisfiedDependencyException(
             'Cannot call ' . __METHOD__ . ' on a 32-bit system, since time_low '
@@ -99,7 +100,7 @@ class DegradedUuid extends Uuid
      * @throws UnsatisfiedDependencyException if called on a 32-bit system
      * @throws UnsupportedOperationException If this UUID is not a version 1 UUID
      */
-    public function getTimestamp()
+    public function getTimestamp(): int
     {
         if ($this->getVersion() != 1) {
             throw new UnsupportedOperationException('Not a time-based UUID');
diff --git a/src/FeatureSet.php b/src/FeatureSet.php
index cb2f9a6..6aead22 100644
--- a/src/FeatureSet.php
+++ b/src/FeatureSet.php
@@ -160,7 +160,7 @@ class FeatureSet
      *
      * @return UuidBuilderInterface
      */
-    public function getBuilder()
+    public function getBuilder(): UuidBuilderInterface
     {
         return $this->builder;
     }
@@ -170,7 +170,7 @@ class FeatureSet
      *
      * @return CodecInterface
      */
-    public function getCodec()
+    public function getCodec(): CodecInterface
     {
         return $this->codec;
     }
@@ -180,7 +180,7 @@ class FeatureSet
      *
      * @return NodeProviderInterface
      */
-    public function getNodeProvider()
+    public function getNodeProvider(): NodeProviderInterface
     {
         return $this->nodeProvider;
     }
@@ -190,7 +190,7 @@ class FeatureSet
      *
      * @return NumberConverterInterface
      */
-    public function getNumberConverter()
+    public function getNumberConverter(): NumberConverterInterface
     {
         return $this->numberConverter;
     }
@@ -200,7 +200,7 @@ class FeatureSet
      *
      * @return RandomGeneratorInterface
      */
-    public function getRandomGenerator()
+    public function getRandomGenerator(): RandomGeneratorInterface
     {
         return $this->randomGenerator;
     }
@@ -210,7 +210,7 @@ class FeatureSet
      *
      * @return TimeGeneratorInterface
      */
-    public function getTimeGenerator()
+    public function getTimeGenerator(): TimeGeneratorInterface
     {
         return $this->timeGenerator;
     }
@@ -220,7 +220,7 @@ class FeatureSet
      *
      * @return ValidatorInterface
      */
-    public function getValidator()
+    public function getValidator(): ValidatorInterface
     {
         return $this->validator;
     }
@@ -254,7 +254,7 @@ class FeatureSet
      * @param bool $useGuids Whether to build UUIDs using the `GuidStringCodec`
      * @return CodecInterface
      */
-    protected function buildCodec($useGuids = false)
+    protected function buildCodec(bool $useGuids = false): CodecInterface
     {
         if ($useGuids) {
             return new GuidStringCodec($this->builder);
@@ -269,7 +269,7 @@ class FeatureSet
      *
      * @return NodeProviderInterface
      */
-    protected function buildNodeProvider()
+    protected function buildNodeProvider(): NodeProviderInterface
     {
         if ($this->ignoreSystemNode) {
             return new RandomNodeProvider();
@@ -287,7 +287,7 @@ class FeatureSet
      *
      * @return NumberConverterInterface
      */
-    protected function buildNumberConverter()
+    protected function buildNumberConverter(): NumberConverterInterface
     {
         if ($this->hasGmp()) {
             return new GmpConverter();
@@ -306,7 +306,7 @@ class FeatureSet
      *
      * @return RandomGeneratorInterface
      */
-    protected function buildRandomGenerator()
+    protected function buildRandomGenerator(): RandomGeneratorInterface
     {
         return (new RandomGeneratorFactory())->getGenerator();
     }
@@ -318,7 +318,7 @@ class FeatureSet
      * @param TimeProviderInterface $timeProvider
      * @return TimeGeneratorInterface
      */
-    protected function buildTimeGenerator(TimeProviderInterface $timeProvider)
+    protected function buildTimeGenerator(TimeProviderInterface $timeProvider): TimeGeneratorInterface
     {
         if ($this->enablePecl) {
             return new PeclUuidTimeGenerator();
@@ -335,9 +335,9 @@ class FeatureSet
      * Determines which time converter to use and returns the configured
      * time converter for this environment
      *
-     * @return \Ramsey\Uuid\Converter\TimeConverterInterface
+     * @return TimeConverterInterface
      */
-    protected function buildTimeConverter()
+    protected function buildTimeConverter(): TimeConverterInterface
     {
         if ($this->is64BitSystem()) {
             return new PhpTimeConverter();
@@ -360,7 +360,7 @@ class FeatureSet
      *
      * @return UuidBuilderInterface
      */
-    protected function buildUuidBuilder()
+    protected function buildUuidBuilder(): UuidBuilderInterface
     {
         if ($this->is64BitSystem()) {
             return new DefaultUuidBuilder($this->numberConverter, $this->timeConverter);
@@ -374,7 +374,7 @@ class FeatureSet
      *
      * @return bool
      */
-    protected function hasBigNumber()
+    protected function hasBigNumber(): bool
     {
         return class_exists('Moontoast\Math\BigNumber') && !$this->disableBigNumber;
     }
@@ -384,7 +384,7 @@ class FeatureSet
      *
      * @return bool
      */
-    protected function hasGmp()
+    protected function hasGmp(): bool
     {
         return extension_loaded('gmp') && !$this->disableGmp;
     }
@@ -394,7 +394,7 @@ class FeatureSet
      *
      * @return bool
      */
-    protected function is64BitSystem()
+    protected function is64BitSystem(): bool
     {
         return PHP_INT_SIZE == 8 && !$this->disable64Bit;
     }
diff --git a/src/Generator/CombGenerator.php b/src/Generator/CombGenerator.php
index 9a9387d..386e0e5 100644
--- a/src/Generator/CombGenerator.php
+++ b/src/Generator/CombGenerator.php
@@ -54,13 +54,13 @@ class CombGenerator implements RandomGeneratorInterface
     /**
      * Generates a string of binary data of the specified length
      *
-     * @param integer $length The number of bytes of random binary data to generate
+     * @param int $length The number of bytes of random binary data to generate
      * @return string A binary string
      * @throws UnsatisfiedDependencyException if `Moontoast\Math\BigNumber` is not present
      * @throws InvalidArgumentException if length is not a positive integer
      * @throws Exception
      */
-    public function generate($length)
+    public function generate(int $length): string
     {
         if ($length < self::TIMESTAMP_BYTES || $length < 0) {
             throw new InvalidArgumentException('Length must be a positive integer.');
@@ -74,7 +74,7 @@ class CombGenerator implements RandomGeneratorInterface
 
         $lsbTime = str_pad($this->converter->toHex($this->timestamp()), self::TIMESTAMP_BYTES * 2, '0', STR_PAD_LEFT);
 
-        return (string) hex2bin(str_pad(bin2hex($hash), $length - self::TIMESTAMP_BYTES, '0') . $lsbTime);
+        return (string) hex2bin(str_pad(bin2hex((string) $hash), $length - self::TIMESTAMP_BYTES, '0') . $lsbTime);
     }
 
     /**
@@ -82,7 +82,7 @@ class CombGenerator implements RandomGeneratorInterface
      *
      * @return string
      */
-    private function timestamp()
+    private function timestamp(): string
     {
         $time = explode(' ', microtime(false));
 
diff --git a/src/Generator/DefaultTimeGenerator.php b/src/Generator/DefaultTimeGenerator.php
index 13a063e..e6670a9 100644
--- a/src/Generator/DefaultTimeGenerator.php
+++ b/src/Generator/DefaultTimeGenerator.php
@@ -80,7 +80,7 @@ class DefaultTimeGenerator implements TimeGeneratorInterface
      * @throws InvalidArgumentException
      * @throws Exception if it was not possible to gather sufficient entropy
      */
-    public function generate($node = null, $clockSeq = null)
+    public function generate($node = null, int $clockSeq = null): string
     {
         $node = $this->getValidNode($node);
 
@@ -92,16 +92,19 @@ class DefaultTimeGenerator implements TimeGeneratorInterface
         // Create a 60-bit time value as a count of 100-nanosecond intervals
         // since 00:00:00.00, 15 October 1582
         $timeOfDay = $this->timeProvider->currentTime();
-        $uuidTime = $this->timeConverter->calculateTime((string) $timeOfDay['sec'], (string) $timeOfDay['usec']);
+        $uuidTime = $this->timeConverter->calculateTime(
+            (string) ($timeOfDay['sec'] ?? ''),
+            (string) ($timeOfDay['usec'] ?? '')
+        );
 
-        $timeHi = BinaryUtils::applyVersion($uuidTime['hi'], 1);
+        $timeHi = BinaryUtils::applyVersion((string) ($uuidTime['hi'] ?? 0), 1);
         $clockSeqHi = BinaryUtils::applyVariant($clockSeq >> 8);
 
         $hex = vsprintf(
             '%08s%04s%04s%02s%02s%012s',
             [
-                $uuidTime['low'],
-                $uuidTime['mid'],
+                $uuidTime['low'] ?? 0,
+                $uuidTime['mid'] ?? 0,
                 sprintf('%04x', $timeHi),
                 sprintf('%02x', $clockSeqHi),
                 sprintf('%02x', $clockSeq & 0xff),
@@ -121,7 +124,7 @@ class DefaultTimeGenerator implements TimeGeneratorInterface
      * @throws InvalidArgumentException
      * @throws Exception
      */
-    protected function getValidNode($node)
+    protected function getValidNode($node): string
     {
         if ($node === null) {
             $node = $this->nodeProvider->getNode();
@@ -132,7 +135,7 @@ class DefaultTimeGenerator implements TimeGeneratorInterface
             $node = sprintf('%012x', $node);
         }
 
-        if (!ctype_xdigit($node) || strlen($node) > 12) {
+        if (!ctype_xdigit((string) $node) || strlen((string) $node) > 12) {
             throw new InvalidArgumentException('Invalid node value');
         }
 
diff --git a/src/Generator/PeclUuidRandomGenerator.php b/src/Generator/PeclUuidRandomGenerator.php
index fc2ef7e..39de343 100644
--- a/src/Generator/PeclUuidRandomGenerator.php
+++ b/src/Generator/PeclUuidRandomGenerator.php
@@ -25,10 +25,10 @@ class PeclUuidRandomGenerator implements RandomGeneratorInterface
     /**
      * Generates a string of random binary data of the specified length
      *
-     * @param integer $length The number of bytes of random binary data to generate
+     * @param int $length The number of bytes of random binary data to generate
      * @return string A binary string
      */
-    public function generate($length)
+    public function generate(int $length): string
     {
         $uuid = uuid_create(UUID_TYPE_RANDOM);
 
diff --git a/src/Generator/PeclUuidTimeGenerator.php b/src/Generator/PeclUuidTimeGenerator.php
index 7ccf16f..693f7e6 100644
--- a/src/Generator/PeclUuidTimeGenerator.php
+++ b/src/Generator/PeclUuidTimeGenerator.php
@@ -29,7 +29,7 @@ class PeclUuidTimeGenerator implements TimeGeneratorInterface
      * @param int $clockSeq Not used in this context
      * @return string A binary string
      */
-    public function generate($node = null, $clockSeq = null)
+    public function generate($node = null, int $clockSeq = null): string
     {
         $uuid = uuid_create(UUID_TYPE_TIME);
 
diff --git a/src/Generator/RandomBytesGenerator.php b/src/Generator/RandomBytesGenerator.php
index cc3d379..63b21bb 100644
--- a/src/Generator/RandomBytesGenerator.php
+++ b/src/Generator/RandomBytesGenerator.php
@@ -28,11 +28,11 @@ class RandomBytesGenerator implements RandomGeneratorInterface
     /**
      * Generates a string of random binary data of the specified length
      *
-     * @param integer $length The number of bytes of random binary data to generate
+     * @param int $length The number of bytes of random binary data to generate
      * @return string A binary string
      * @throws Exception if it was not possible to gather sufficient entropy
      */
-    public function generate($length)
+    public function generate(int $length): string
     {
         return random_bytes($length);
     }
diff --git a/src/Generator/RandomGeneratorFactory.php b/src/Generator/RandomGeneratorFactory.php
index 3911062..ee968ec 100644
--- a/src/Generator/RandomGeneratorFactory.php
+++ b/src/Generator/RandomGeneratorFactory.php
@@ -24,7 +24,7 @@ class RandomGeneratorFactory
      *
      * @return RandomGeneratorInterface
      */
-    public static function getGenerator()
+    public static function getGenerator(): RandomGeneratorInterface
     {
         return new RandomBytesGenerator();
     }
diff --git a/src/Generator/RandomGeneratorInterface.php b/src/Generator/RandomGeneratorInterface.php
index b791d60..266d444 100644
--- a/src/Generator/RandomGeneratorInterface.php
+++ b/src/Generator/RandomGeneratorInterface.php
@@ -27,11 +27,11 @@ interface RandomGeneratorInterface
     /**
      * Generates a string of random binary data of the specified length
      *
-     * @param integer $length The number of bytes of random binary data to generate
-     * @return string A binary string
+     * @param int $length The number of bytes of random binary data to generate
+     * @return string|null A binary string
      * @throws UnsatisfiedDependencyException if `Moontoast\Math\BigNumber` is not present
      * @throws InvalidArgumentException
      * @throws Exception if it was not possible to gather sufficient entropy
      */
-    public function generate($length);
+    public function generate(int $length): ?string;
 }
diff --git a/src/Generator/RandomLibAdapter.php b/src/Generator/RandomLibAdapter.php
index a6c2fab..20c7659 100644
--- a/src/Generator/RandomLibAdapter.php
+++ b/src/Generator/RandomLibAdapter.php
@@ -52,10 +52,10 @@ class RandomLibAdapter implements RandomGeneratorInterface
     /**
      * Generates a string of random binary data of the specified length
      *
-     * @param integer $length The number of bytes of random binary data to generate
-     * @return string A binary string
+     * @param int $length The number of bytes of random binary data to generate
+     * @return string|null A binary string
      */
-    public function generate($length)
+    public function generate(int $length): ?string
     {
         return $this->generator->generate($length);
     }
diff --git a/src/Generator/TimeGeneratorFactory.php b/src/Generator/TimeGeneratorFactory.php
index 24d501b..f1129a8 100644
--- a/src/Generator/TimeGeneratorFactory.php
+++ b/src/Generator/TimeGeneratorFactory.php
@@ -61,7 +61,7 @@ class TimeGeneratorFactory
      *
      * @return TimeGeneratorInterface
      */
-    public function getGenerator()
+    public function getGenerator(): TimeGeneratorInterface
     {
         return new DefaultTimeGenerator(
             $this->nodeProvider,
diff --git a/src/Generator/TimeGeneratorInterface.php b/src/Generator/TimeGeneratorInterface.php
index 27c7459..cf0cb2e 100644
--- a/src/Generator/TimeGeneratorInterface.php
+++ b/src/Generator/TimeGeneratorInterface.php
@@ -39,5 +39,5 @@ interface TimeGeneratorInterface
      * @throws InvalidArgumentException
      * @throws Exception if it was not possible to gather sufficient entropy
      */
-    public function generate($node = null, $clockSeq = null);
+    public function generate($node = null, int $clockSeq = null): string;
 }
diff --git a/src/Provider/Node/FallbackNodeProvider.php b/src/Provider/Node/FallbackNodeProvider.php
index a30aaec..9918c1d 100644
--- a/src/Provider/Node/FallbackNodeProvider.php
+++ b/src/Provider/Node/FallbackNodeProvider.php
@@ -46,7 +46,7 @@ class FallbackNodeProvider implements NodeProviderInterface
      * @return string|null System node ID as a hexadecimal string
      * @throws Exception
      */
-    public function getNode()
+    public function getNode(): ?string
     {
         foreach ($this->nodeProviders as $provider) {
             if ($node = $provider->getNode()) {
diff --git a/src/Provider/Node/RandomNodeProvider.php b/src/Provider/Node/RandomNodeProvider.php
index 79ec63c..b284a63 100644
--- a/src/Provider/Node/RandomNodeProvider.php
+++ b/src/Provider/Node/RandomNodeProvider.php
@@ -31,7 +31,7 @@ class RandomNodeProvider implements NodeProviderInterface
      * @return string System node ID as a hexadecimal string
      * @throws Exception if it was not possible to gather sufficient entropy
      */
-    public function getNode()
+    public function getNode(): string
     {
         $nodeBytes = random_bytes(6);
 
diff --git a/src/Provider/Node/SystemNodeProvider.php b/src/Provider/Node/SystemNodeProvider.php
index 892cbba..0308924 100644
--- a/src/Provider/Node/SystemNodeProvider.php
+++ b/src/Provider/Node/SystemNodeProvider.php
@@ -25,7 +25,7 @@ class SystemNodeProvider implements NodeProviderInterface
     /**
      * Returns the system node ID
      *
-     * @return string|false System node ID as a hexadecimal string, or false if it is not found
+     * @return string|null|false System node ID as a hexadecimal string, or false if it is not found
      */
     public function getNode()
     {
@@ -66,7 +66,7 @@ class SystemNodeProvider implements NodeProviderInterface
      * @codeCoverageIgnore
      * @return string
      */
-    protected function getIfconfig()
+    protected function getIfconfig(): string
     {
         if (strpos(strtolower((string) ini_get('disable_functions')), 'passthru') !== false) {
             return '';
diff --git a/src/Provider/NodeProviderInterface.php b/src/Provider/NodeProviderInterface.php
index b6f721f..a150456 100644
--- a/src/Provider/NodeProviderInterface.php
+++ b/src/Provider/NodeProviderInterface.php
@@ -25,7 +25,7 @@ interface NodeProviderInterface
     /**
      * Returns the system node ID
      *
-     * @return string System node ID as a hexadecimal string
+     * @return string|null|false System node ID as a hexadecimal string
      * @throws Exception if it was not possible to gather sufficient entropy
      */
     public function getNode();
diff --git a/src/Provider/Time/FixedTimeProvider.php b/src/Provider/Time/FixedTimeProvider.php
index 6fafe70..d743a57 100644
--- a/src/Provider/Time/FixedTimeProvider.php
+++ b/src/Provider/Time/FixedTimeProvider.php
@@ -51,7 +51,7 @@ class FixedTimeProvider implements TimeProviderInterface
      * @param int $value The `usec` value to set
      * @return void
      */
-    public function setUsec($value)
+    public function setUsec(int $value)
     {
         $this->fixedTime['usec'] = $value;
     }
@@ -62,7 +62,7 @@ class FixedTimeProvider implements TimeProviderInterface
      * @param int $value The `sec` value to set
      * @return void
      */
-    public function setSec($value)
+    public function setSec(int $value)
     {
         $this->fixedTime['sec'] = $value;
     }
@@ -72,7 +72,7 @@ class FixedTimeProvider implements TimeProviderInterface
      *
      * @return int[] Array containing `sec` and `usec` components of a timestamp
      */
-    public function currentTime()
+    public function currentTime(): array
     {
         return $this->fixedTime;
     }
diff --git a/src/Provider/Time/SystemTimeProvider.php b/src/Provider/Time/SystemTimeProvider.php
index 6442985..eb8ab1a 100644
--- a/src/Provider/Time/SystemTimeProvider.php
+++ b/src/Provider/Time/SystemTimeProvider.php
@@ -26,7 +26,7 @@ class SystemTimeProvider implements TimeProviderInterface
      *
      * @return int[] Array containing `sec` and `usec` components of a timestamp
      */
-    public function currentTime()
+    public function currentTime(): array
     {
         return gettimeofday();
     }
diff --git a/src/Provider/TimeProviderInterface.php b/src/Provider/TimeProviderInterface.php
index ef8099d..1bd6263 100644
--- a/src/Provider/TimeProviderInterface.php
+++ b/src/Provider/TimeProviderInterface.php
@@ -25,5 +25,5 @@ interface TimeProviderInterface
      *
      * @return int[] Array guaranteed to contain `sec` and `usec` components of a timestamp
      */
-    public function currentTime();
+    public function currentTime(): array;
 }
diff --git a/src/Uuid.php b/src/Uuid.php
index 37fc36f..5953250 100644
--- a/src/Uuid.php
+++ b/src/Uuid.php
@@ -15,6 +15,7 @@
 namespace Ramsey\Uuid;
 
 use DateTimeImmutable;
+use DateTimeInterface;
 use Exception;
 use InvalidArgumentException;
 use Ramsey\Uuid\Codec\CodecInterface;
@@ -206,7 +207,7 @@ class Uuid implements UuidInterface
      * @return string
      * @link http://www.php.net/manual/en/language.oop5.magic.php#object.tostring
      */
-    public function __toString()
+    public function __toString(): string
     {
         return $this->toString();
     }
@@ -218,7 +219,7 @@ class Uuid implements UuidInterface
      * @return string
      * @link http://php.net/manual/en/class.jsonserializable.php
      */
-    public function jsonSerialize()
+    public function jsonSerialize(): string
     {
         return $this->toString();
     }
@@ -230,7 +231,7 @@ class Uuid implements UuidInterface
      * @return string
      * @link http://php.net/manual/en/class.serializable.php
      */
-    public function serialize()
+    public function serialize(): string
     {
         return $this->toString();
     }
@@ -252,7 +253,7 @@ class Uuid implements UuidInterface
         $this->fields = $uuid->fields;
     }
 
-    public function compareTo(UuidInterface $other)
+    public function compareTo(UuidInterface $other): int
     {
         if ($this->getMostSignificantBitsHex() < $other->getMostSignificantBitsHex()) {
             return -1;
@@ -273,7 +274,7 @@ class Uuid implements UuidInterface
         return 0;
     }
 
-    public function equals($other)
+    public function equals(?object $other): bool
     {
         if (!$other instanceof UuidInterface) {
             return false;
@@ -282,7 +283,7 @@ class Uuid implements UuidInterface
         return $this->compareTo($other) == 0;
     }
 
-    public function getBytes()
+    public function getBytes(): string
     {
         return $this->codec->encodeBinary($this);
     }
@@ -293,12 +294,12 @@ class Uuid implements UuidInterface
      *
      * @return int Unsigned 8-bit integer value of clock_seq_hi_and_reserved
      */
-    public function getClockSeqHiAndReserved()
+    public function getClockSeqHiAndReserved(): int
     {
         return (int) hexdec($this->getClockSeqHiAndReservedHex());
     }
 
-    public function getClockSeqHiAndReservedHex()
+    public function getClockSeqHiAndReservedHex(): string
     {
         return $this->fields['clock_seq_hi_and_reserved'];
     }
@@ -308,12 +309,12 @@ class Uuid implements UuidInterface
      *
      * @return int Unsigned 8-bit integer value of clock_seq_low
      */
-    public function getClockSeqLow()
+    public function getClockSeqLow(): int
     {
         return (int) hexdec($this->getClockSeqLowHex());
     }
 
-    public function getClockSeqLowHex()
+    public function getClockSeqLowHex(): string
     {
         return $this->fields['clock_seq_low'];
     }
@@ -334,17 +335,17 @@ class Uuid implements UuidInterface
      * @return int Unsigned 14-bit integer value of clock sequence
      * @link http://tools.ietf.org/html/rfc4122#section-4.1.5
      */
-    public function getClockSequence()
+    public function getClockSequence(): int
     {
         return ($this->getClockSeqHiAndReserved() & 0x3f) << 8 | $this->getClockSeqLow();
     }
 
-    public function getClockSequenceHex()
+    public function getClockSequenceHex(): string
     {
         return sprintf('%04x', $this->getClockSequence());
     }
 
-    public function getNumberConverter()
+    public function getNumberConverter(): NumberConverterInterface
     {
         return $this->numberConverter;
     }
@@ -352,7 +353,7 @@ class Uuid implements UuidInterface
     /**
      * @inheritdoc
      */
-    public function getDateTime()
+    public function getDateTime(): DateTimeInterface
     {
         if ($this->getVersion() != 1) {
             throw new UnsupportedOperationException('Not a time-based UUID');
@@ -381,7 +382,7 @@ class Uuid implements UuidInterface
      * @return array The UUID fields represented as integer values
      * @link http://tools.ietf.org/html/rfc4122#section-4.1.2
      */
-    public function getFields()
+    public function getFields(): array
     {
         return [
             'time_low' => $this->getTimeLow(),
@@ -393,12 +394,12 @@ class Uuid implements UuidInterface
         ];
     }
 
-    public function getFieldsHex()
+    public function getFieldsHex(): array
     {
         return $this->fields;
     }
 
-    public function getHex()
+    public function getHex(): string
     {
         return str_replace('-', '', $this->toString());
     }
@@ -422,7 +423,7 @@ class Uuid implements UuidInterface
         return $this->numberConverter->fromHex($this->getLeastSignificantBitsHex());
     }
 
-    public function getLeastSignificantBitsHex()
+    public function getLeastSignificantBitsHex(): string
     {
         return sprintf(
             '%02s%02s%012s',
@@ -443,7 +444,7 @@ class Uuid implements UuidInterface
         return $this->numberConverter->fromHex($this->getMostSignificantBitsHex());
     }
 
-    public function getMostSignificantBitsHex()
+    public function getMostSignificantBitsHex(): string
     {
         return sprintf(
             '%08s%04s%04s',
@@ -477,12 +478,12 @@ class Uuid implements UuidInterface
      * @return int Unsigned 48-bit integer value of node
      * @link http://tools.ietf.org/html/rfc4122#section-4.1.6
      */
-    public function getNode()
+    public function getNode(): int
     {
         return (int) hexdec($this->getNodeHex());
     }
 
-    public function getNodeHex()
+    public function getNodeHex(): string
     {
         return $this->fields['node'];
     }
@@ -493,12 +494,12 @@ class Uuid implements UuidInterface
      *
      * @return int Unsigned 16-bit integer value of time_hi_and_version
      */
-    public function getTimeHiAndVersion()
+    public function getTimeHiAndVersion(): int
     {
         return (int) hexdec($this->getTimeHiAndVersionHex());
     }
 
-    public function getTimeHiAndVersionHex()
+    public function getTimeHiAndVersionHex(): string
     {
         return $this->fields['time_hi_and_version'];
     }
@@ -508,12 +509,12 @@ class Uuid implements UuidInterface
      *
      * @return int Unsigned 32-bit integer value of time_low
      */
-    public function getTimeLow()
+    public function getTimeLow(): int
     {
         return (int) hexdec($this->getTimeLowHex());
     }
 
-    public function getTimeLowHex()
+    public function getTimeLowHex(): string
     {
         return $this->fields['time_low'];
     }
@@ -523,12 +524,12 @@ class Uuid implements UuidInterface
      *
      * @return int Unsigned 16-bit integer value of time_mid
      */
-    public function getTimeMid()
+    public function getTimeMid(): int
     {
         return (int) hexdec($this->getTimeMidHex());
     }
 
-    public function getTimeMidHex()
+    public function getTimeMidHex(): string
     {
         return $this->fields['time_mid'];
     }
@@ -549,7 +550,7 @@ class Uuid implements UuidInterface
      * @throws UnsupportedOperationException If this UUID is not a version 1 UUID
      * @link http://tools.ietf.org/html/rfc4122#section-4.1.4
      */
-    public function getTimestamp()
+    public function getTimestamp(): int
     {
         if ($this->getVersion() != 1) {
             throw new UnsupportedOperationException('Not a time-based UUID');
@@ -561,7 +562,7 @@ class Uuid implements UuidInterface
     /**
      * @inheritdoc
      */
-    public function getTimestampHex()
+    public function getTimestampHex(): string
     {
         if ($this->getVersion() != 1) {
             throw new UnsupportedOperationException('Not a time-based UUID');
@@ -575,12 +576,12 @@ class Uuid implements UuidInterface
         );
     }
 
-    public function getUrn()
+    public function getUrn(): string
     {
         return 'urn:uuid:' . $this->toString();
     }
 
-    public function getVariant()
+    public function getVariant(): int
     {
         $clockSeq = $this->getClockSeqHiAndReserved();
 
@@ -599,7 +600,7 @@ class Uuid implements UuidInterface
         return self::RESERVED_FUTURE;
     }
 
-    public function getVersion()
+    public function getVersion(): ?int
     {
         if ($this->getVariant() == self::RFC_4122) {
             return (int) (($this->getTimeHiAndVersion() >> 12) & 0x0f);
@@ -608,7 +609,7 @@ class Uuid implements UuidInterface
         return null;
     }
 
-    public function toString()
+    public function toString(): string
     {
         return $this->codec->encode($this);
     }
@@ -618,7 +619,7 @@ class Uuid implements UuidInterface
      *
      * @return UuidFactoryInterface
      */
-    public static function getFactory()
+    public static function getFactory(): UuidFactoryInterface
     {
         if (!self::$factory) {
             self::$factory = new UuidFactory();
@@ -646,7 +647,7 @@ class Uuid implements UuidInterface
      * @throws InvalidUuidStringException
      * @throws InvalidArgumentException
      */
-    public static function fromBytes($bytes)
+    public static function fromBytes(string $bytes): UuidInterface
     {
         return self::getFactory()->fromBytes($bytes);
     }
@@ -658,7 +659,7 @@ class Uuid implements UuidInterface
      * @return UuidInterface
      * @throws InvalidUuidStringException
      */
-    public static function fromString($name)
+    public static function fromString(string $name): UuidInterface
     {
         return self::getFactory()->fromString($name);
     }
@@ -671,7 +672,7 @@ class Uuid implements UuidInterface
      * @throws UnsatisfiedDependencyException if `Moontoast\Math\BigNumber` is not present
      * @throws InvalidUuidStringException
      */
-    public static function fromInteger($integer)
+    public static function fromInteger(string $integer): UuidInterface
     {
         return self::getFactory()->fromInteger($integer);
     }
@@ -682,7 +683,7 @@ class Uuid implements UuidInterface
      * @param string $uuid The string UUID to test
      * @return boolean
      */
-    public static function isValid($uuid)
+    public static function isValid(string $uuid): bool
     {
         return self::getFactory()->getValidator()->validate($uuid);
     }
@@ -701,7 +702,7 @@ class Uuid implements UuidInterface
      * @throws InvalidArgumentException
      * @throws Exception if it was not possible to gather sufficient entropy
      */
-    public static function uuid1($node = null, $clockSeq = null)
+    public static function uuid1($node = null, ?int $clockSeq = null): UuidInterface
     {
         return self::getFactory()->uuid1($node, $clockSeq);
     }
@@ -715,7 +716,7 @@ class Uuid implements UuidInterface
      * @return UuidInterface
      * @throws InvalidUuidStringException
      */
-    public static function uuid3($ns, $name)
+    public static function uuid3($ns, string $name): UuidInterface
     {
         return self::getFactory()->uuid3($ns, $name);
     }
@@ -728,7 +729,7 @@ class Uuid implements UuidInterface
      * @throws InvalidArgumentException
      * @throws Exception
      */
-    public static function uuid4()
+    public static function uuid4(): UuidInterface
     {
         return self::getFactory()->uuid4();
     }
@@ -742,7 +743,7 @@ class Uuid implements UuidInterface
      * @return UuidInterface
      * @throws InvalidUuidStringException
      */
-    public static function uuid5($ns, $name)
+    public static function uuid5($ns, string $name): UuidInterface
     {
         return self::getFactory()->uuid5($ns, $name);
     }
diff --git a/src/UuidFactory.php b/src/UuidFactory.php
index f865531..9a2b309 100644
--- a/src/UuidFactory.php
+++ b/src/UuidFactory.php
@@ -83,7 +83,7 @@ class UuidFactory implements UuidFactoryInterface
      *
      * @return CodecInterface
      */
-    public function getCodec()
+    public function getCodec(): CodecInterface
     {
         return $this->codec;
     }
@@ -104,7 +104,7 @@ class UuidFactory implements UuidFactoryInterface
      *
      * @return NodeProviderInterface
      */
-    public function getNodeProvider()
+    public function getNodeProvider(): NodeProviderInterface
     {
         return $this->nodeProvider;
     }
@@ -114,7 +114,7 @@ class UuidFactory implements UuidFactoryInterface
      *
      * @return RandomGeneratorInterface
      */
-    public function getRandomGenerator()
+    public function getRandomGenerator(): RandomGeneratorInterface
     {
         return $this->randomGenerator;
     }
@@ -124,7 +124,7 @@ class UuidFactory implements UuidFactoryInterface
      *
      * @return TimeGeneratorInterface
      */
-    public function getTimeGenerator()
+    public function getTimeGenerator(): TimeGeneratorInterface
     {
         return $this->timeGenerator;
     }
@@ -145,7 +145,7 @@ class UuidFactory implements UuidFactoryInterface
      *
      * @return NumberConverterInterface
      */
-    public function getNumberConverter()
+    public function getNumberConverter(): NumberConverterInterface
     {
         return $this->numberConverter;
     }
@@ -177,7 +177,7 @@ class UuidFactory implements UuidFactoryInterface
      *
      * @return UuidBuilderInterface $builder
      */
-    public function getUuidBuilder()
+    public function getUuidBuilder(): UuidBuilderInterface
     {
         return $this->uuidBuilder;
     }
@@ -196,7 +196,7 @@ class UuidFactory implements UuidFactoryInterface
     /**
      * @return ValidatorInterface
      */
-    public function getValidator()
+    public function getValidator(): ValidatorInterface
     {
         return $this->validator;
     }
@@ -210,7 +210,10 @@ class UuidFactory implements UuidFactoryInterface
         $this->validator = $validator;
     }
 
-    public function fromBytes($bytes)
+    /**
+     * @inheritdoc
+     */
+    public function fromBytes(string $bytes): UuidInterface
     {
         return $this->codec->decodeBytes($bytes);
     }
@@ -218,7 +221,7 @@ class UuidFactory implements UuidFactoryInterface
     /**
      * @inheritdoc
      */
-    public function fromString($uuid)
+    public function fromString(string $uuid): UuidInterface
     {
         $uuid = strtolower($uuid);
         return $this->codec->decode($uuid);
@@ -227,7 +230,7 @@ class UuidFactory implements UuidFactoryInterface
     /**
      * @inheritdoc
      */
-    public function fromInteger($integer)
+    public function fromInteger($integer): UuidInterface
     {
         $hex = $this->numberConverter->toHex($integer);
         $hex = str_pad($hex, 32, '0', STR_PAD_LEFT);
@@ -238,7 +241,7 @@ class UuidFactory implements UuidFactoryInterface
     /**
      * @inheritdoc
      */
-    public function uuid1($node = null, $clockSeq = null)
+    public function uuid1($node = null, ?int $clockSeq = null): UuidInterface
     {
         $bytes = $this->timeGenerator->generate($node, $clockSeq);
         $hex = bin2hex($bytes);
@@ -249,7 +252,7 @@ class UuidFactory implements UuidFactoryInterface
     /**
      * @inheritdoc
      */
-    public function uuid3($ns, $name)
+    public function uuid3($ns, string $name): UuidInterface
     {
         return $this->uuidFromNsAndName($ns, $name, 3, 'md5');
     }
@@ -257,14 +260,14 @@ class UuidFactory implements UuidFactoryInterface
     /**
      * @inheritdoc
      */
-    public function uuid4()
+    public function uuid4(): UuidInterface
     {
         $bytes = $this->randomGenerator->generate(16);
 
         // When converting the bytes to hex, it turns into a 32-character
         // hexadecimal string that looks a lot like an MD5 hash, so at this
         // point, we can just pass it to uuidFromHashedName.
-        $hex = bin2hex($bytes);
+        $hex = bin2hex((string) $bytes);
 
         return $this->uuidFromHashedName($hex, 4);
     }
@@ -272,7 +275,7 @@ class UuidFactory implements UuidFactoryInterface
     /**
      * @inheritdoc
      */
-    public function uuid5($ns, $name)
+    public function uuid5($ns, string $name): UuidInterface
     {
         return $this->uuidFromNsAndName($ns, $name, 5, 'sha1');
     }
@@ -287,7 +290,7 @@ class UuidFactory implements UuidFactoryInterface
      *     see {@see \Ramsey\Uuid\UuidInterface::getFieldsHex()} for array structure.
      * @return UuidInterface
      */
-    public function uuid(array $fields)
+    public function uuid(array $fields): UuidInterface
     {
         return $this->uuidBuilder->build($this->codec, $fields);
     }
@@ -303,7 +306,7 @@ class UuidFactory implements UuidFactoryInterface
      * @return UuidInterface
      * @throws InvalidUuidStringException
      */
-    protected function uuidFromNsAndName($ns, $name, $version, $hashFunction)
+    protected function uuidFromNsAndName($ns, string $name, int $version, callable $hashFunction): UuidInterface
     {
         if (!($ns instanceof UuidInterface)) {
             $ns = $this->codec->decode($ns);
@@ -322,7 +325,7 @@ class UuidFactory implements UuidFactoryInterface
      * @param int $version The UUID version to set for this hash (1, 3, 4, or 5)
      * @return UuidInterface
      */
-    protected function uuidFromHashedName($hash, $version)
+    protected function uuidFromHashedName(string $hash, int $version): UuidInterface
     {
         $timeHi = BinaryUtils::applyVersion(substr($hash, 12, 4), $version);
         $clockSeqHi = BinaryUtils::applyVariant((int) hexdec(substr($hash, 16, 2)));
diff --git a/src/UuidFactoryInterface.php b/src/UuidFactoryInterface.php
index 471ad4b..700a8c7 100644
--- a/src/UuidFactoryInterface.php
+++ b/src/UuidFactoryInterface.php
@@ -29,7 +29,7 @@ interface UuidFactoryInterface
     /**
      * @return ValidatorInterface
      */
-    public function getValidator();
+    public function getValidator(): ValidatorInterface;
 
     /**
      * Generate a version 1 UUID from a host ID, sequence number, and the current time.
@@ -45,7 +45,7 @@ interface UuidFactoryInterface
      * @throws InvalidArgumentException
      * @throws Exception if it was not possible to gather sufficient entropy
      */
-    public function uuid1($node = null, $clockSeq = null);
+    public function uuid1($node = null, ?int $clockSeq = null): UuidInterface;
 
     /**
      * Generate a version 3 UUID based on the MD5 hash of a namespace identifier
@@ -56,7 +56,7 @@ interface UuidFactoryInterface
      * @return UuidInterface
      * @throws InvalidUuidStringException
      */
-    public function uuid3($ns, $name);
+    public function uuid3($ns, string $name): UuidInterface;
 
     /**
      * Generate a version 4 (random) UUID.
@@ -66,7 +66,7 @@ interface UuidFactoryInterface
      * @throws InvalidArgumentException
      * @throws Exception
      */
-    public function uuid4();
+    public function uuid4(): UuidInterface;
 
     /**
      * Generate a version 5 UUID based on the SHA-1 hash of a namespace
@@ -77,7 +77,7 @@ interface UuidFactoryInterface
      * @return UuidInterface
      * @throws InvalidUuidStringException
      */
-    public function uuid5($ns, $name);
+    public function uuid5($ns, string $name): UuidInterface;
 
     /**
      * Creates a UUID from a byte string.
@@ -87,7 +87,7 @@ interface UuidFactoryInterface
      * @throws InvalidUuidStringException
      * @throws InvalidArgumentException if string has not 16 characters
      */
-    public function fromBytes($bytes);
+    public function fromBytes(string $bytes): UuidInterface;
 
     /**
      * Creates a UUID from the string standard representation
@@ -96,7 +96,7 @@ interface UuidFactoryInterface
      * @return UuidInterface
      * @throws InvalidUuidStringException
      */
-    public function fromString($uuid);
+    public function fromString(string $uuid): UuidInterface;
 
     /**
      * Creates a `Uuid` from an integer representation
@@ -110,5 +110,5 @@ interface UuidFactoryInterface
      * @throws UnsatisfiedDependencyException if `Moontoast\Math\BigNumber` is not present
      * @throws InvalidUuidStringException
      */
-    public function fromInteger($integer);
+    public function fromInteger($integer): UuidInterface;
 }
diff --git a/src/UuidInterface.php b/src/UuidInterface.php
index 5af050f..f73f6fd 100644
--- a/src/UuidInterface.php
+++ b/src/UuidInterface.php
@@ -40,7 +40,7 @@ interface UuidInterface extends JsonSerializable, Serializable
      * @param UuidInterface $other UUID to which this UUID is compared
      * @return int -1, 0 or 1 as this UUID is less than, equal to, or greater than `$uuid`
      */
-    public function compareTo(UuidInterface $other);
+    public function compareTo(UuidInterface $other): int;
 
     /**
      * Compares this object to the specified object.
@@ -49,10 +49,10 @@ interface UuidInterface extends JsonSerializable, Serializable
      * object, has the same variant, and contains the same value, bit for bit,
      * as this UUID.
      *
-     * @param object $other
+     * @param object|null $other
      * @return bool True if `$other` is equal to this UUID
      */
-    public function equals($other);
+    public function equals(?object $other): bool;
 
     /**
      * Returns the UUID as a 16-byte string (containing the six integer fields
@@ -60,21 +60,21 @@ interface UuidInterface extends JsonSerializable, Serializable
      *
      * @return string
      */
-    public function getBytes();
+    public function getBytes(): string;
 
     /**
      * Returns the number converter to use for converting hex values to/from integers.
      *
      * @return NumberConverterInterface
      */
-    public function getNumberConverter();
+    public function getNumberConverter(): NumberConverterInterface;
 
     /**
      * Returns the hexadecimal value of the UUID.
      *
      * @return string
      */
-    public function getHex();
+    public function getHex(): string;
 
     /**
      * Returns an array of the fields of this UUID, with keys named according
@@ -93,7 +93,7 @@ interface UuidInterface extends JsonSerializable, Serializable
      *
      * @return array The UUID fields represented as hexadecimal values
      */
-    public function getFieldsHex();
+    public function getFieldsHex(): array;
 
     /**
      * Returns the high field of the clock sequence multiplexed with the variant
@@ -101,21 +101,21 @@ interface UuidInterface extends JsonSerializable, Serializable
      *
      * @return string Hexadecimal value of clock_seq_hi_and_reserved
      */
-    public function getClockSeqHiAndReservedHex();
+    public function getClockSeqHiAndReservedHex(): string;
 
     /**
      * Returns the low field of the clock sequence (bits 73-80 of the UUID).
      *
      * @return string Hexadecimal value of clock_seq_low
      */
-    public function getClockSeqLowHex();
+    public function getClockSeqLowHex(): string;
 
     /**
      * Returns the clock sequence value associated with this UUID.
      *
      * @return string Hexadecimal value of clock sequence
      */
-    public function getClockSequenceHex();
+    public function getClockSequenceHex(): string;
 
     /**
      * Returns a PHP object that implements `DateTimeInterface` representing
@@ -130,7 +130,7 @@ interface UuidInterface extends JsonSerializable, Serializable
      * @throws UnsatisfiedDependencyException if called in a 32-bit system and
      *     `Moontoast\Math\BigNumber` is not present
      */
-    public function getDateTime();
+    public function getDateTime(): DateTimeInterface;
 
     /**
      * Returns the integer value of the UUID, converted to an appropriate number
@@ -146,14 +146,14 @@ interface UuidInterface extends JsonSerializable, Serializable
      *
      * @return string Hexadecimal value of least significant bits
      */
-    public function getLeastSignificantBitsHex();
+    public function getLeastSignificantBitsHex(): string;
 
     /**
      * Returns the most significant 64 bits of this UUID's 128 bit value.
      *
      * @return string Hexadecimal value of most significant bits
      */
-    public function getMostSignificantBitsHex();
+    public function getMostSignificantBitsHex(): string;
 
     /**
      * Returns the node value associated with this UUID
@@ -179,7 +179,7 @@ interface UuidInterface extends JsonSerializable, Serializable
      * @return string Hexadecimal value of node
      * @link http://tools.ietf.org/html/rfc4122#section-4.1.6
      */
-    public function getNodeHex();
+    public function getNodeHex(): string;
 
     /**
      * Returns the high field of the timestamp multiplexed with the version
@@ -187,21 +187,21 @@ interface UuidInterface extends JsonSerializable, Serializable
      *
      * @return string Hexadecimal value of time_hi_and_version
      */
-    public function getTimeHiAndVersionHex();
+    public function getTimeHiAndVersionHex(): string;
 
     /**
      * Returns the low field of the timestamp (the first 32 bits of the UUID).
      *
      * @return string Hexadecimal value of time_low
      */
-    public function getTimeLowHex();
+    public function getTimeLowHex(): string;
 
     /**
      * Returns the middle field of the timestamp (bits 33-48 of the UUID).
      *
      * @return string Hexadecimal value of time_mid
      */
-    public function getTimeMidHex();
+    public function getTimeMidHex(): string;
 
     /**
      * Returns the timestamp value associated with this UUID.
@@ -219,7 +219,7 @@ interface UuidInterface extends JsonSerializable, Serializable
      * @throws UnsupportedOperationException If this UUID is not a version 1 UUID
      * @link http://tools.ietf.org/html/rfc4122#section-4.1.4
      */
-    public function getTimestampHex();
+    public function getTimestampHex(): string;
 
     /**
      * Returns the string representation of the UUID as a URN.
@@ -227,7 +227,7 @@ interface UuidInterface extends JsonSerializable, Serializable
      * @return string
      * @link http://en.wikipedia.org/wiki/Uniform_Resource_Name
      */
-    public function getUrn();
+    public function getUrn(): string;
 
     /**
      * Returns the variant number associated with this UUID.
@@ -243,7 +243,7 @@ interface UuidInterface extends JsonSerializable, Serializable
      * @return int
      * @link http://tools.ietf.org/html/rfc4122#section-4.1.1
      */
-    public function getVariant();
+    public function getVariant(): int;
 
     /**
      * Returns the version number associated with this UUID.
@@ -263,19 +263,19 @@ interface UuidInterface extends JsonSerializable, Serializable
      * @return int|null
      * @link http://tools.ietf.org/html/rfc4122#section-4.1.3
      */
-    public function getVersion();
+    public function getVersion(): ?int;
 
     /**
      * Returns a string representation of this UUID.
      *
      * @return string
      */
-    public function toString();
+    public function toString(): string;
 
     /**
      * Allows casting this UUID to a string representation.
      *
      * @return string
      */
-    public function __toString();
+    public function __toString(): string;
 }
diff --git a/src/Validator/Validator.php b/src/Validator/Validator.php
index 3bbf2e4..95704a2 100644
--- a/src/Validator/Validator.php
+++ b/src/Validator/Validator.php
@@ -33,7 +33,7 @@ class Validator implements ValidatorInterface
      * @param string $uuid
      * @return bool Returns TRUE if the string was validated as a valid UUID or FALSE on failure
      */
-    public function validate($uuid)
+    public function validate($uuid): bool
     {
         $uuid = str_replace(['urn:', 'uuid:', 'URN:', 'UUID:', '{', '}'], '', $uuid);
 
diff --git a/src/Validator/ValidatorInterface.php b/src/Validator/ValidatorInterface.php
index 6a688e4..8cbd0e5 100644
--- a/src/Validator/ValidatorInterface.php
+++ b/src/Validator/ValidatorInterface.php
@@ -26,5 +26,5 @@ interface ValidatorInterface
      * @param string $uuid
      * @return bool Returns TRUE if the string was validated as a valid UUID or FALSE on failure
      */
-    public function validate($uuid);
+    public function validate(string $uuid): bool;
 }