Implement Package::implementation() to load implementations of a given type

Author: thekid

src/main/php/lang/reflection/Package.class.php

@@ -122,6 +122,21 @@ public function type($name) {
     throw new IllegalArgumentException('Given type '.$type.' is not in package '.$this->name);
   }
 
+  /**
+   * Returns an implementation for a given type
+   *
+   * @param  string|lang.reflection.Type $type
+   * @param  string $name
+   * @return lang.reflection.Type
+   * @throws lang.IllegalArgumentException
+   */
+  public function implementation($type, $name) {
+    $impl= $this->type($name);
+    if ($impl->is($type)) return $impl;
+
+    throw new IllegalArgumentException('Given type '.$impl->name().' is not an implementation of '.$type);
+  }
+
   /** @return string */
   public function hashCode() { return md5($this->name); }
 

src/test/php/lang/reflection/unittest/PackageTest.class.php

@@ -1,10 +1,19 @@
 <?php namespace lang\reflection\unittest;
 
-use lang\IllegalArgumentException;
 use lang\reflection\Package;
+use lang\reflection\unittest\fixture\{Instruction, CreateInstruction};
+use lang\{Reflection, IllegalArgumentException};
 use test\{Assert, Expect, Test, Values};
 
 class PackageTest {
+  const FIXTURES= 'lang.reflection.unittest.fixture';
+
+  /** @return iterable */
+  private function instructions() {
+    yield [Instruction::class, 'class literal'];
+    yield ['lang.reflection.unittest.fixture.Instruction', 'class name'];
+    yield [Reflection::type(Instruction::class), 'type'];
+  }
 
   #[Test, Values(['lang.reflection', 'lang\reflection', 'lang.reflection.'])]
   public function name($arg) {
@@ -102,4 +111,30 @@ public function type_via_full_name() {
   public function type_with_namespace() {
     (new Package('lang'))->type('util.Date');
   }
+
+  #[Test, Values(from: 'instructions')]
+  public function implementation_by_name($type) {
+    Assert::equals(
+      Reflection::type(CreateInstruction::class),
+      (new Package(self::FIXTURES))->implementation($type, 'CreateInstruction')
+    );
+  }
+
+  #[Test, Values(from: 'instructions')]
+  public function implementation_by_class($type) {
+    Assert::equals(
+      Reflection::type(CreateInstruction::class),
+      (new Package(self::FIXTURES))->implementation($type, CreateInstruction::class)
+    );
+  }
+
+  #[Test, Expect(class: IllegalArgumentException::class, message: '/Given type util.Date is not in package .+/')]
+  public function implementation_not_in_package() {
+    (new Package(self::FIXTURES))->implementation(Instruction::class, 'util.Date');
+  }
+
+  #[Test, Expect(class: IllegalArgumentException::class, message: '/Given type .+ is not an implementation of lang.Runnable/')]
+  public function not_an_implementation() {
+    (new Package(self::FIXTURES))->implementation('lang.Runnable', 'CreateInstruction');
+  }
 }

src/test/php/lang/reflection/unittest/fixture/CreateInstruction.class.php

@@ -0,0 +1,5 @@
+<?php namespace lang\reflection\unittest\fixture;
+
+class CreateInstruction implements Instruction {
+  
+}

src/test/php/lang/reflection/unittest/fixture/Instruction.class.php

@@ -0,0 +1,5 @@
+<?php namespace lang\reflection\unittest\fixture;
+
+interface Instruction {
+  
+}