Added callback extractor.

src/Builder/Extractor/CallbackExtractorBuilder.php

@@ -0,0 +1,39 @@
+<?php
+/*
+ * This file is part of the jojo1981/data-resolver package
+ *
+ * Copyright (c) 2020 Joost Nijhuis <jnijhuis81@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed in the root of the source code
+ */
+namespace Jojo1981\DataResolver\Builder\Extractor;
+
+use Jojo1981\DataResolver\Builder\ExtractorBuilderInterface;
+use Jojo1981\DataResolver\Extractor\CallbackExtractor;
+use Jojo1981\DataResolver\Extractor\ExtractorInterface;
+
+/**
+ * @package Jojo1981\DataResolver\Builder\Extractor
+ */
+class CallbackExtractorBuilder implements ExtractorBuilderInterface
+{
+    /** @var callable */
+    private $callback;
+
+    /**
+     * @param callable $callback
+     */
+    public function __construct(callable $callback)
+    {
+        $this->callback = $callback;
+    }
+
+    /**
+     * @return CallbackExtractor
+     */
+    public function build(): ExtractorInterface
+    {
+        return new CallbackExtractor($this->callback);
+    }
+}

src/Builder/ResolverBuilder.php

@@ -90,6 +90,18 @@ public function flatten(ResolverBuilder $resolverBuilder): self
         return $result;
     }
 
+    /**
+     * @param callable $callback
+     * @return $this
+     */
+    public function callback(callable $callback): self
+    {
+        $result = clone $this;
+        $result->extractors[] = $this->extractorBuilderFactory->getCallbackExtractorBuilder($callback)->build();
+
+        return $result;
+    }
+
     /**
      * @param PredicateBuilderInterface $predicateBuilder
      * @return Resolver

src/Extractor/CallbackExtractor.php

@@ -0,0 +1,39 @@
+<?php
+/*
+ * This file is part of the jojo1981/data-resolver package
+ *
+ * Copyright (c) 2020 Joost Nijhuis <jnijhuis81@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed in the root of the source code
+ */
+namespace Jojo1981\DataResolver\Extractor;
+
+use Jojo1981\DataResolver\Resolver\Context;
+use function call_user_func;
+
+/**
+ * @package Jojo1981\DataResolver\Extractor
+ */
+class CallbackExtractor implements ExtractorInterface
+{
+    /** @var callable */
+    private $callback;
+
+    /**
+     * @param callable $callback
+     */
+    public function __construct(callable $callback)
+    {
+        $this->callback = $callback;
+    }
+
+    /**
+     * @param Context $context
+     * @return mixed
+     */
+    public function extract(Context $context)
+    {
+        return call_user_func($this->callback, $context->copy()->getData());
+    }
+}

src/Factory/ExtractorBuilderFactory.php

@@ -10,6 +10,7 @@
 namespace Jojo1981\DataResolver\Factory;
 
 use Jojo1981\DataResolver\Builder\Extractor\AllExtractorBuilder;
+use Jojo1981\DataResolver\Builder\Extractor\CallbackExtractorBuilder;
 use Jojo1981\DataResolver\Builder\Extractor\CompositeExtractorBuilder;
 use Jojo1981\DataResolver\Builder\Extractor\CountExtractorBuilder;
 use Jojo1981\DataResolver\Builder\Extractor\HasPropertyExtractorBuilder;
@@ -128,6 +129,15 @@ public function getCountExtractorBuilder(): CountExtractorBuilder
         return new CountExtractorBuilder($this->sequenceHandler);
     }
 
+    /**
+     * @param callable $callback
+     * @return CallbackExtractorBuilder
+     */
+    public function getCallbackExtractorBuilder(callable $callback): CallbackExtractorBuilder
+    {
+        return new CallbackExtractorBuilder($callback);
+    }
+
     /**
      * @return SumExtractorBuilder
      */

tests/Extractor/CallbackExtractorTest.php

@@ -0,0 +1,71 @@
+<?php
+/*
+ * This file is part of the jojo1981/data-resolver package
+ *
+ * Copyright (c) 2020 Joost Nijhuis <jnijhuis81@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed in the root of the source code
+ */
+namespace tests\Jojo1981\DataResolver\Extractor;
+
+use Jojo1981\DataResolver\Extractor\CallbackExtractor;
+use Jojo1981\DataResolver\Resolver\Context;
+use PHPUnit\Framework\ExpectationFailedException;
+use PHPUnit\Framework\TestCase;
+use Prophecy\Exception\Doubler\ClassNotFoundException;
+use Prophecy\Exception\Doubler\DoubleException;
+use Prophecy\Exception\Doubler\InterfaceNotFoundException;
+use Prophecy\Exception\Prophecy\ObjectProphecyException;
+use Prophecy\Prophecy\ObjectProphecy;
+use SebastianBergmann\RecursionContext\InvalidArgumentException;
+
+/**
+ * @package tests\Jojo1981\DataResolver\Extractor
+ */
+class CallbackExtractorTest extends TestCase
+{
+    /** @var ObjectProphecy|Context */
+    private $originalContext;
+
+    /** @var ObjectProphecy|Context */
+    private $copiedContext;
+
+    /**
+     * @throws DoubleException
+     * @throws InterfaceNotFoundException
+     * @throws ClassNotFoundException
+     * @return void
+     */
+    protected function setUp(): void
+    {
+        $this->originalContext = $this->prophesize(Context::class);
+        $this->copiedContext = $this->prophesize(Context::class);
+    }
+
+
+    /**
+     * @test
+     *
+     * @throws InvalidArgumentException
+     * @throws ObjectProphecyException
+     * @throws ExpectationFailedException
+     * @return void
+     */
+    public function extractShouldReturnTheResultFromTheCallback(): void
+    {
+        $this->originalContext->copy()->willReturn($this->copiedContext)->shouldBeCalled();
+        $this->originalContext->getData()->shouldNotBeCalled();
+        $this->copiedContext->getData()->willReturn('my-data')->shouldBeCalledOnce();
+
+        $invokerCounter = 0;
+        $callback = function (string $item) use (&$invokerCounter): string {
+            $this->assertEquals('my-data', $item);
+            $invokerCounter++;
+
+            return 'newResult';
+        };
+        $this->assertEquals('newResult', (new CallbackExtractor($callback))->extract($this->originalContext->reveal()));
+        $this->assertEquals(1, $invokerCounter);
+    }
+}