Add GeneratorFactory interface to allow factory creation of Generators

CHANGELOG.md

@@ -4,6 +4,8 @@ on [Keep a CHANGELOG](http://keepachangelog.com/). This project adheres to
 [Semantic Versioning](http://semver.org/).
 
 ## Unreleased
+### Added
+- GeneratorFactory interface to allow factory creation of Generators
 
 ## [1.7.0] - 2017-08-17
 ### Added

generator-core/src/main/java/uk/gov/justice/maven/generator/io/files/parser/core/GeneratorFactory.java

@@ -0,0 +1,6 @@
+package uk.gov.justice.maven.generator.io.files.parser.core;
+
+public interface GeneratorFactory<T> {
+
+    Generator<T> create();
+}

generator-plugin-it/pom.xml

@@ -114,7 +114,7 @@
                         <id>internal-jsons</id>
                         <configuration>
                             <generatorName>
-                                uk.gov.justice.maven.generator.io.files.parser.json.test.JsonTitleAppendingGenerator
+                                uk.gov.justice.maven.generator.io.files.parser.json.test.JsonTitleAppendingGeneratorFactory
                             </generatorName>
                             <parserName>uk.gov.justice.maven.generator.io.files.parser.JsonSchemaFileParser</parserName>
                             <basePackageName>uk.gov.justice.api</basePackageName>

generator-plugin/src/main/java/uk/gov/justice/maven/generator/io/files/parser/generator/GenerateGoalProcessor.java

@@ -1,8 +1,8 @@
 package uk.gov.justice.maven.generator.io.files.parser.generator;
 
+import uk.gov.justice.maven.generator.io.files.parser.FileParser;
 import uk.gov.justice.maven.generator.io.files.parser.core.GeneratorConfig;
 import uk.gov.justice.maven.generator.io.files.parser.io.FileTreeScannerFactory;
-import uk.gov.justice.maven.generator.io.files.parser.FileParser;
 
 import java.io.IOException;
 import java.nio.file.Path;
@@ -13,19 +13,20 @@
  */
 public class GenerateGoalProcessor {
 
-    private final GeneratorFactory generatorFactory;
+    private final MojoGeneratorFactory mojoGeneratorFactory;
     private final FileParser parser;
 
     private final FileTreeScannerFactory scannerFactory;
 
-    public GenerateGoalProcessor(final GeneratorFactory generatorFactory,
+    public GenerateGoalProcessor(final MojoGeneratorFactory mojoGeneratorFactory,
                                  final FileTreeScannerFactory scannerFactory,
                                  final FileParser parser) {
-        this.generatorFactory = generatorFactory;
+        this.mojoGeneratorFactory = mojoGeneratorFactory;
         this.scannerFactory = scannerFactory;
         this.parser = parser;
     }
 
+    @SuppressWarnings("unchecked")
     public void generate(final GenerateGoalConfig config) throws IOException {
 
         final String[] includes = config.getIncludes().toArray(new String[config.getIncludes().size()]);
@@ -37,6 +38,6 @@ public void generate(final GenerateGoalConfig config) throws IOException {
         final Collection<Path> paths = scannerFactory.create().find(config.getSourceDirectory(), includes, excludes);
         parser
                 .parse(config.getSourceDirectory(), paths)
-                .forEach(file -> generatorFactory.instanceOf(config.getGeneratorName()).run(file, generatorConfig));
+                .forEach(file -> mojoGeneratorFactory.instanceOf(config.getGeneratorName()).run(file, generatorConfig));
     }
 }

generator-plugin/src/main/java/uk/gov/justice/maven/generator/io/files/parser/generator/GenerateMojo.java

@@ -3,9 +3,9 @@
 import static java.lang.Class.forName;
 import static org.apache.maven.plugins.annotations.ResolutionScope.COMPILE_PLUS_RUNTIME;
 
+import uk.gov.justice.maven.generator.io.files.parser.FileParser;
 import uk.gov.justice.maven.generator.io.files.parser.common.BasicMojo;
 import uk.gov.justice.maven.generator.io.files.parser.io.FileTreeScannerFactory;
-import uk.gov.justice.maven.generator.io.files.parser.FileParser;
 
 import java.io.File;
 import java.nio.file.Path;
@@ -57,13 +57,18 @@ public class GenerateMojo extends BasicMojo {
     public void execute() throws MojoExecutionException {
         if (!skip) {
             configureDefaultFileIncludes();
+
             project.addCompileSourceRoot(outputDirectory.getPath());
             project.addTestCompileSourceRoot(outputDirectory.getPath());
+
             final List<Path> sourcePaths = new ArrayList<>();
-            project.getCompileSourceRoots().stream().forEach(root -> sourcePaths.add(Paths.get(root)));
+
+            project.getCompileSourceRoots().forEach(root -> sourcePaths.add(Paths.get(root)));
+
             try {
                 FileUtils.forceMkdir(outputDirectory);
-                new GenerateGoalProcessor(new GeneratorFactory(),
+                new GenerateGoalProcessor(
+                        new MojoGeneratorFactory(),
                         new FileTreeScannerFactory(),
                         (FileParser) forName(parserName).newInstance())
                         .generate(configuration(sourcePaths));

generator-plugin/src/main/java/uk/gov/justice/maven/generator/io/files/parser/generator/MojoGeneratorFactory.java

@@ -0,0 +1,53 @@
+package uk.gov.justice.maven.generator.io.files.parser.generator;
+
+import static java.util.Arrays.asList;
+
+import uk.gov.justice.maven.generator.io.files.parser.core.Generator;
+import uk.gov.justice.maven.generator.io.files.parser.core.GeneratorFactory;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Factory for generators
+ */
+public class MojoGeneratorFactory {
+
+    private final Map<String, Generator> generators = new HashMap<>();
+
+    /**
+     * Returns an instance of a generator.
+     *
+     * @param generatorName fully qualified classname that implements {@link Generator}
+     * @return the generator
+     */
+    public Generator instanceOf(final String generatorName) {
+
+        if (!generators.containsKey(generatorName)) {
+            generators.put(generatorName, createGenerator(generatorName));
+        }
+
+        return generators.get(generatorName);
+    }
+
+    private Generator createGenerator(final String generatorName) {
+
+        try {
+            final Class<?> generatorClass = Class.forName(generatorName);
+
+            if (isGeneratorFactory(generatorClass)) {
+                final GeneratorFactory generatorFactory = (GeneratorFactory) generatorClass.newInstance();
+
+                return generatorFactory.create();
+            }
+
+            return (Generator) generatorClass.newInstance();
+        } catch (final ClassNotFoundException | IllegalAccessException | InstantiationException e) {
+            throw new IllegalArgumentException(String.format("Could not instantiate generator %s", generatorName), e);
+        }
+    }
+
+    private boolean isGeneratorFactory(final Class<?> generatorClass) {
+        return asList(generatorClass.getInterfaces()).contains(GeneratorFactory.class);
+    }
+}

generator-plugin/src/test/java/uk/gov/justice/maven/generator/io/files/parser/generator/GenerateGoalProcessorTest.java

@@ -14,12 +14,12 @@
 import static org.mockito.Mockito.verifyZeroInteractions;
 import static org.mockito.Mockito.when;
 
+import uk.gov.justice.maven.generator.io.files.parser.FileParser;
+import uk.gov.justice.maven.generator.io.files.parser.RamlFileParser;
 import uk.gov.justice.maven.generator.io.files.parser.core.Generator;
 import uk.gov.justice.maven.generator.io.files.parser.core.GeneratorConfig;
 import uk.gov.justice.maven.generator.io.files.parser.io.FileTreeScanner;
 import uk.gov.justice.maven.generator.io.files.parser.io.FileTreeScannerFactory;
-import uk.gov.justice.maven.generator.io.files.parser.FileParser;
-import uk.gov.justice.maven.generator.io.files.parser.RamlFileParser;
 
 import java.io.File;
 import java.io.IOException;
@@ -53,7 +53,7 @@ public class GenerateGoalProcessorTest {
     @Mock
     private Generator generator;
     @Mock
-    private GeneratorFactory generatorFactory;
+    private MojoGeneratorFactory mojoGeneratorFactory;
     @Mock
     private FileTreeScannerFactory scannerFactory;
     @Mock
@@ -70,7 +70,7 @@ public class GenerateGoalProcessorTest {
     public void setup() {
         String generatorName = "mock.generator";
 
-        when(generatorFactory.instanceOf(generatorName)).thenReturn(generator);
+        when(mojoGeneratorFactory.instanceOf(generatorName)).thenReturn(generator);
         when(config.getGeneratorName()).thenReturn(generatorName);
         when(config.getSourceDirectory()).thenReturn(sourceDirectory.getRoot().toPath());
         when(config.getIncludes()).thenReturn(asList(includes));
@@ -111,6 +111,7 @@ public void shouldCallGeneratorWithRamlFilesAndConfig() throws Exception {
     }
 
     @Test
+    @SuppressWarnings("unchecked")
     public void shouldCallGeneratorWithEmptyRamlForEmptyFile() throws Exception {
         File ramlFile = sourceDirectory.newFile("file3.raml");
 
@@ -129,6 +130,7 @@ public void shouldCallGeneratorWithEmptyRamlForEmptyFile() throws Exception {
     }
 
     @Test
+    @SuppressWarnings("unchecked")
     public void shouldPassPatternsToFileTreeScanner() throws Exception {
 
         final String[] customIncludes = {"**/*.txt"};
@@ -161,7 +163,7 @@ public void shouldNotInstatiateGeneratorIfNoRamlFilesToProcess() throws IOExcept
         when(scanner.find(any(Path.class), any(String[].class), any(String[].class))).thenReturn(emptyList());
         generateGoalProcessor.generate(config);
 
-        verifyZeroInteractions(generatorFactory);
+        verifyZeroInteractions(mojoGeneratorFactory);
 
     }
 }

generator-plugin/src/test/java/uk/gov/justice/maven/generator/io/files/parser/generator/GeneratorFactoryTest.java → generator-plugin/src/test/java/uk/gov/justice/maven/generator/io/files/parser/generator/MojoGeneratorFactoryTest.java

@@ -8,20 +8,21 @@
 import uk.gov.justice.maven.generator.io.files.parser.core.Generator;
 import uk.gov.justice.maven.generator.io.files.parser.generator.generators.NonInstantiableTestGenerator;
 import uk.gov.justice.maven.generator.io.files.parser.generator.generators.TestGenerator;
+import uk.gov.justice.maven.generator.io.files.parser.generator.generators.TestGeneratorFactory;
 
 import org.junit.Before;
 import org.junit.Test;
 
 /**
- * Unit tests for the {@link GeneratorFactory} class.
+ * Unit tests for the {@link MojoGeneratorFactory} class.
  */
-public class GeneratorFactoryTest {
+public class MojoGeneratorFactoryTest {
 
-    private GeneratorFactory factory;
+    private MojoGeneratorFactory factory;
 
     @Before
     public void setup() {
-        factory = new GeneratorFactory();
+        factory = new MojoGeneratorFactory();
     }
 
     @Test
@@ -30,6 +31,12 @@ public void shouldCreateGenerator() {
         assertThat(generator, is(instanceOf(TestGenerator.class)));
     }
 
+    @Test
+    public void shouldCreateGeneratorFromFactory() {
+        final Generator generator = factory.instanceOf(TestGeneratorFactory.class.getName());
+        assertThat(generator, is(instanceOf(TestGenerator.class)));
+    }
+
     @Test
     public void shouldCreateOnlyOneInstanceOfGenerator() {
         final Generator generator1 = factory.instanceOf(TestGenerator.class.getName());
@@ -38,19 +45,27 @@ public void shouldCreateOnlyOneInstanceOfGenerator() {
         assertThat(generator1, sameInstance(generator2));
     }
 
+    @Test
+    public void shouldCreateOnlyOneInstanceOfGeneratorFromFactory() {
+        final Generator generator1 = factory.instanceOf(TestGeneratorFactory.class.getName());
+        final Generator generator2 = factory.instanceOf(TestGeneratorFactory.class.getName());
+
+        assertThat(generator1, sameInstance(generator2));
+    }
+
     @Test(expected = IllegalArgumentException.class)
     public void shouldThrowExceptionIfClassDoesNotExists() {
         factory.instanceOf("nonexistent.GeneratorClass");
     }
 
     @Test
-    public void shouldThrowAnIllegalArgumentExceptionIfThegeneratorCannotBeInstantiated() throws Exception {
+    public void shouldThrowExceptionIfThegeneratorCannotBeInstantiated() throws Exception {
 
         try {
             factory.instanceOf(NonInstantiableTestGenerator.class.getName());
         } catch (final IllegalArgumentException expected) {
             assertThat(expected.getMessage(), is("Could not instantiate generator " + NonInstantiableTestGenerator.class.getName()));
-            assertThat(expected.getCause(), is(instanceOf(NoSuchMethodException.class)));
+            assertThat(expected.getCause(), is(instanceOf(IllegalAccessException.class)));
         }
     }
 }

generator-plugin/src/test/java/uk/gov/justice/maven/generator/io/files/parser/generator/generators/TestGeneratorFactory.java

@@ -0,0 +1,12 @@
+package uk.gov.justice.maven.generator.io.files.parser.generator.generators;
+
+import uk.gov.justice.maven.generator.io.files.parser.core.Generator;
+import uk.gov.justice.maven.generator.io.files.parser.core.GeneratorFactory;
+
+public class TestGeneratorFactory implements GeneratorFactory {
+
+    @Override
+    public Generator create() {
+        return new TestGenerator();
+    }
+}

json-generator-for-testing/src/test/java/uk/gov/justice/maven/generator/io/files/parser/json/test/FilePathProvider.java

@@ -0,0 +1,17 @@
+package uk.gov.justice.maven.generator.io.files.parser.json.test;
+
+import static java.lang.String.format;
+
+import uk.gov.justice.maven.generator.io.files.parser.core.GeneratorConfig;
+
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+public class FilePathProvider {
+
+    public static final String FILE_NAME = "json-titles.txt";
+
+    public Path filePath(final GeneratorConfig generatorConfig) {
+        return Paths.get(format("%s/%s", generatorConfig.getOutputDirectory().toString(), FILE_NAME));
+    }
+}