Create JctFileManagers utility class

This provides static methods to create instances of the
default JctFileManagerImpl and JctFileManagerFactoryImpl
classes in third-party libraries outside this API.

Author: ascopes

java-compiler-testing/src/main/java/io/github/ascopes/jct/filemanagers/JctFileManagers.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2022 - 2023, the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.github.ascopes.jct.filemanagers;
+
+import io.github.ascopes.jct.compilers.JctCompiler;
+import io.github.ascopes.jct.filemanagers.impl.JctFileManagerFactoryImpl;
+import io.github.ascopes.jct.filemanagers.impl.JctFileManagerImpl;
+import io.github.ascopes.jct.utils.UtilityClass;
+import org.apiguardian.api.API;
+import org.apiguardian.api.API.Status;
+
+/**
+ * Helpers to create instances of default implementations for file managers.
+ *
+ * @author Ashley Scopes
+ * @since 1.1.0
+ */
+@API(since = "1.1.0", status = Status.STABLE)
+public final class JctFileManagers extends UtilityClass {
+  private JctFileManagers() {
+    // Static-only class.
+  }
+
+  /**
+   * Create a new default implementation of a file manager.
+   *
+   * @param release the Java release to use for the file manager.
+   * @return the file manager instance.
+   */
+  public static JctFileManager newJctFileManager(String release) {
+    return new JctFileManagerImpl(release);
+  }
+
+  /**
+   * Create a new default implementation of a file manager factory.
+   *
+   * @param compiler the JctCompiler to bind any file managers to.
+   * @return the file manager factory instance.
+   */
+  public static JctFileManagerFactory newJctFileManagerFactory(JctCompiler compiler) {
+    return new JctFileManagerFactoryImpl(compiler);
+  }
+}

java-compiler-testing/src/main/java/io/github/ascopes/jct/filemanagers/impl/JctFileManagerFactoryImpl.java

@@ -56,6 +56,18 @@ public JctFileManagerFactoryImpl(JctCompiler compiler) {
     this.compiler = compiler;
   }
 
+  /**
+   * Get the compiler that was set on this file manager factory.
+   *
+   * @return the compiler
+   * @since 1.1.0
+   */
+  @API(since = "1.1.0", status = Status.INTERNAL)
+  @VisibleForTestingOnly
+  public JctCompiler getCompiler() {
+    return compiler;
+  }
+
   @Override
   public JctFileManager createFileManager(Workspace workspace) {
     var release = compiler.getEffectiveRelease();

java-compiler-testing/src/test/java/io/github/ascopes/jct/tests/helpers/UtilityClassTestTemplate.java

@@ -69,6 +69,14 @@ default void testClassExtendsUtilityClass() {
         .hasSuperclass(UtilityClass.class);
   }
 
+  @DisplayName("Class should not implement any interfaces")
+  @Test
+  default void classShouldNotImplementAnyInterfaces() {
+    assertThat(getTypeBeingTested().getInterfaces())
+        .withFailMessage("Expected utility class to not implement any interfaces")
+        .isEmpty();
+  }
+
   @DisplayName("Class should be final")
   @Test
   default void testClassIsFinal() {

java-compiler-testing/src/test/java/io/github/ascopes/jct/tests/unit/filemanagers/JctFileManagersTest.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2022 - 2023, the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.github.ascopes.jct.tests.unit.filemanagers;
+
+import static io.github.ascopes.jct.tests.helpers.Fixtures.someRelease;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+import io.github.ascopes.jct.compilers.JctCompiler;
+import io.github.ascopes.jct.filemanagers.JctFileManagers;
+import io.github.ascopes.jct.filemanagers.impl.JctFileManagerFactoryImpl;
+import io.github.ascopes.jct.filemanagers.impl.JctFileManagerImpl;
+import io.github.ascopes.jct.tests.helpers.UtilityClassTestTemplate;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+/**
+ * {@link JctFileManagers} tests.
+ *
+ * @author Ashley Scopes
+ */
+@DisplayName("JctFileManagers tests")
+class JctFileManagersTest implements UtilityClassTestTemplate {
+
+  @Override
+  public Class<?> getTypeBeingTested() {
+    return JctFileManagers.class;
+  }
+
+  @DisplayName(".newJctFileManager(String) returns a new JctFileManagerImpl instance")
+  @Test
+  void newJctFileManagerReturnsNewJctFileManagerImplInstance() {
+    // Given
+    var release = someRelease();
+
+    // When
+    var fileManager = JctFileManagers.newJctFileManager(release);
+
+    // Then
+    assertThat(fileManager).isInstanceOf(JctFileManagerImpl.class);
+    assertThat(fileManager.getEffectiveRelease()).isEqualTo(release);
+  }
+
+  @DisplayName(
+      ".newJctFileManagerFactory(JctCompiler) returns a new JctFileManagerFactoryImpl instance"
+  )
+  @Test
+  void newJctFileManagerFactoryReturnsNewJctFileManagerFactoryImplInstance() {
+    // Given
+    var compiler = mock(JctCompiler.class);
+
+    // When
+    var fileManagerFactory = JctFileManagers.newJctFileManagerFactory(compiler);
+
+    // Then
+    assertThat(fileManagerFactory).isInstanceOf(JctFileManagerFactoryImpl.class);
+    assertThat(((JctFileManagerFactoryImpl) fileManagerFactory).getCompiler()).isSameAs(compiler);
+  }
+}

java-compiler-testing/src/test/java/io/github/ascopes/jct/tests/unit/filemanagers/impl/JctFileManagerFactoryImplTest.java

@@ -71,6 +71,13 @@ class JctFileManagerFactoryImplTest {
   @Spy
   JctFileManagerFactoryImpl factory;
 
+  @DisplayName(".getCompiler() returns the compiler")
+  @Test
+  void getCompilerReturnsTheCompiler() {
+    // Then
+    assertThat(factory.getCompiler()).isSameAs(compiler);
+  }
+
   @DisplayName("Created file managers use the effective release")
   @Test
   void createdFileManagersUseTheEffectiveRelease() {