Keep track of original ProjectDescription

See gh-1023

initializr-web/src/main/java/io/spring/initializr/web/autoconfigure/InitializrAutoConfiguration.java

@@ -28,6 +28,8 @@ import io.spring.initializr.generator.io.SimpleIndentStrategy;
 import io.spring.initializr.generator.io.template.MustacheTemplateRenderer;
 import io.spring.initializr.generator.io.template.TemplateRenderer;
 import io.spring.initializr.generator.project.ProjectDirectoryFactory;
+import io.spring.initializr.generator.project.diff.DefaultProjectDescriptionDiffFactory;
+import io.spring.initializr.generator.project.diff.ProjectDescriptionDiffFactory;
 import io.spring.initializr.metadata.DependencyMetadataProvider;
 import io.spring.initializr.metadata.InitializrMetadata;
 import io.spring.initializr.metadata.InitializrMetadataBuilder;
@@ -129,6 +131,12 @@ public class InitializrAutoConfiguration {
 		return new DefaultDependencyMetadataProvider();
 	}
 
+	@Bean
+	@ConditionalOnMissingBean
+	ProjectDescriptionDiffFactory projectDescriptionDiffFactory() {
+		return new DefaultProjectDescriptionDiffFactory();
+	}
+
 	/**
 	 * Initializr web configuration.
 	 */

initializr-web/src/test/java/io/spring/initializr/web/autoconfigure/InitializrAutoConfigurationTests.java

@@ -17,6 +17,7 @@
 package io.spring.initializr.web.autoconfigure;
 
 import io.spring.initializr.generator.io.template.TemplateRenderer;
+import io.spring.initializr.generator.project.diff.ProjectDescriptionDiffFactory;
 import io.spring.initializr.metadata.DependencyMetadataProvider;
 import io.spring.initializr.metadata.InitializrMetadataProvider;
 import io.spring.initializr.web.controller.CommandLineMetadataController;
@@ -63,6 +64,11 @@ class InitializrAutoConfigurationTests {
 		this.contextRunner.run((context) -> assertThat(context).hasSingleBean(TemplateRenderer.class));
 	}
 
+	@Test
+	void autoConfigRegistersDiffFactory() {
+		this.contextRunner.run((context) -> assertThat(context).hasSingleBean(ProjectDescriptionDiffFactory.class));
+	}
+
 	@Test
 	void autoConfigWhenTemplateRendererBeanPresentDoesNotRegisterTemplateRenderer() {
 		this.contextRunner.withUserConfiguration(CustomTemplateRendererConfiguration.class).run((context) -> {

initializr-web/src/test/java/io/spring/initializr/web/controller/custom/CustomProjectContributor.java

@@ -44,6 +44,7 @@ class CustomProjectContributor implements ProjectContributor {
 				&& ((CustomProjectDescription) this.description).isCustomFlag()) {
 			Files.createFile(projectRoot.resolve("custom.txt"));
 		}
+
 	}
 
 }

initializr-web/src/test/java/io/spring/initializr/web/controller/custom/CustomProjectDescription.java

@@ -28,6 +28,20 @@ class CustomProjectDescription extends MutableProjectDescription {
 
 	private boolean customFlag;
 
+	CustomProjectDescription() {
+		super();
+	}
+
+	CustomProjectDescription(final CustomProjectDescription source) {
+		super(source);
+		setCustomFlag(source.isCustomFlag());
+	}
+
+	@Override
+	public CustomProjectDescription createCopy() {
+		return new CustomProjectDescription(this);
+	}
+
 	boolean isCustomFlag() {
 		return this.customFlag;
 	}

initializr-web/src/test/java/io/spring/initializr/web/controller/custom/CustomProjectDescriptionDiff.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2012-2019 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
+ *
+ *      https://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.spring.initializr.web.controller.custom;
+
+import java.util.function.BiConsumer;
+
+import io.spring.initializr.generator.project.diff.ProjectDescriptionDiff;
+
+/**
+ * Extends the base {@link ProjectDescriptionDiff} to provide convenient diff methods on
+ * {@link CustomProjectDescription}.
+ *
+ * @author cbono
+ */
+class CustomProjectDescriptionDiff extends ProjectDescriptionDiff {
+
+	CustomProjectDescriptionDiff(final CustomProjectDescription original) {
+		super(original);
+	}
+
+	/**
+	 * Optionally calls the specified consumer if the {@code customFlag} is different on
+	 * the original source description and the specified current description.
+	 * @param current the description to test against
+	 * @param consumer to call if the property has changed
+	 */
+	void ifCUstomFlagChanged(final CustomProjectDescription current, final BiConsumer<Boolean, Boolean> consumer) {
+		final CustomProjectDescription original = (CustomProjectDescription) super.getOriginal();
+		if (original.isCustomFlag() != current.isCustomFlag()) {
+			consumer.accept(original.isCustomFlag(), current.isCustomFlag());
+		}
+	}
+
+}

initializr-web/src/test/java/io/spring/initializr/web/controller/custom/CustomProjectDescriptionDiffFactory.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2012-2019 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
+ *
+ *      https://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.spring.initializr.web.controller.custom;
+
+import io.spring.initializr.generator.project.diff.ProjectDescriptionDiff;
+import io.spring.initializr.generator.project.diff.ProjectDescriptionDiffFactory;
+
+/**
+ * A custom {@link ProjectDescriptionDiffFactory} implementation that creates custom
+ * {@link CustomProjectDescriptionDiff} instances.
+ *
+ * @author cbono
+ */
+public class CustomProjectDescriptionDiffFactory implements ProjectDescriptionDiffFactory<CustomProjectDescription> {
+
+	@Override
+	public ProjectDescriptionDiff create(final CustomProjectDescription description) {
+		return new CustomProjectDescriptionDiff(description);
+	}
+
+}

initializr-web/src/test/java/io/spring/initializr/web/controller/custom/CustomProjectDescriptionDiffTest.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2012-2019 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
+ *
+ *      https://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.spring.initializr.web.controller.custom;
+
+import io.spring.initializr.generator.buildsystem.BuildSystem;
+import io.spring.initializr.generator.buildsystem.maven.MavenBuildSystem;
+import io.spring.initializr.generator.language.Language;
+import io.spring.initializr.generator.language.java.JavaLanguage;
+import io.spring.initializr.generator.packaging.Packaging;
+import io.spring.initializr.generator.version.Version;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
+
+/**
+ * Simple sanity test around the custom diff extension model.
+ */
+class CustomProjectDescriptionDiffTest {
+
+	@Test
+	void sanityCheck() {
+
+		CustomProjectDescription description = customProjectDescription();
+		CustomProjectDescriptionDiffFactory diffFactory = new CustomProjectDescriptionDiffFactory();
+		CustomProjectDescriptionDiff diff = (CustomProjectDescriptionDiff) diffFactory.create(description);
+
+		// copied
+		assertThat(diff.getOriginal()).usingRecursiveComparison().isEqualTo(description);
+		assertThat(diff.getOriginal()).isNotSameAs(description);
+
+		// no changes
+		diff.ifCUstomFlagChanged(description, (v1, v2) -> fail("Values should not have changed"));
+
+		// changes
+		boolean originalValue = description.isCustomFlag();
+		description.setCustomFlag(!originalValue);
+
+		// TODO could use the CallTrackingBiConsumer that I used in initializr-generator
+		// tests but then where to put it?
+		final boolean[] called = { false };
+		diff.ifCUstomFlagChanged(description, (prev, curr) -> {
+			assertThat(prev).isEqualTo(originalValue);
+			assertThat(curr).isEqualTo(description.isCustomFlag());
+			called[0] = true;
+		});
+		assertThat(called[0]).isTrue();
+	}
+
+	private CustomProjectDescription customProjectDescription() {
+		CustomProjectDescription description = new CustomProjectDescription();
+		description.setBuildSystem(BuildSystem.forId(MavenBuildSystem.ID));
+		description.setLanguage(Language.forId(JavaLanguage.ID, "11"));
+		description.setPlatformVersion(Version.parse("2.2.0.RELEASE"));
+		description.setGroupId("com.example");
+		description.setArtifactId("demo");
+		description.setName("demo");
+		description.setVersion("0.0.8");
+		description.setApplicationName("DemoApplication");
+		description.setPackageName("com.example.demo");
+		description.setPackaging(Packaging.forId("jar"));
+		description.setBaseDirectory(".");
+		description.setCustomFlag(true);
+		return description;
+	}
+
+}

initializr-web/src/test/java/io/spring/initializr/web/controller/custom/ProjectGenerationControllerCustomRequestIntegrationTests.java

@@ -79,6 +79,11 @@ public class ProjectGenerationControllerCustomRequestIntegrationTests
 			return new CustomProjectGenerationController(metadataProvider, projectGenerationInvoker);
 		}
 
+		@Bean
+		CustomProjectDescriptionDiffFactory customProjectDescriptionDiffFactory() {
+			return new CustomProjectDescriptionDiffFactory();
+		}
+
 	}
 
 	static class CustomProjectRequestToDescriptionConverter