Add project request post processing

This commit introduces `ProjectRequestPostProcessor` as a mean to modify
an incoming `ProjectRequest` before and after its resolution against the
meta-data.

By default, all beans of that type are invoked automatically and they
are ordered against their `@Order` or `Ordered` settings.

Closes gh-260

initializr-generator/src/main/groovy/io/spring/initializr/generator/ProjectGenerator.groovy

@@ -55,6 +55,9 @@ class ProjectGenerator {
 	@Autowired
 	InitializrMetadataProvider metadataProvider
 
+	@Autowired
+	ProjectRequestResolver requestResolver
+
 	@Autowired
 	ProjectResourceLocator projectResourceLocator = new ProjectResourceLocator()
 
@@ -210,12 +213,12 @@ class ProjectGenerator {
 	 * @param request the request to handle
 	 * @return a model for that request
 	 */
-	protected Map resolveModel(ProjectRequest request) {
-		Assert.notNull request.bootVersion, 'boot version must not be null'
+	protected Map resolveModel(ProjectRequest originalRequest) {
+		Assert.notNull originalRequest.bootVersion, 'boot version must not be null'
 		def model = [:]
 		def metadata = metadataProvider.get()
 
-		request.resolve(metadata)
+		ProjectRequest request = requestResolver.resolve(originalRequest, metadata)
 
 		// request resolved so we can log what has been requested
 		def dependencies = request.resolvedDependencies

initializr-generator/src/main/groovy/io/spring/initializr/generator/ProjectRequestPostProcessor.groovy

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2012-2016 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.spring.initializr.generator
+
+import io.spring.initializr.metadata.InitializrMetadata
+
+/**
+ * Project generation hook that allows for custom modification of {@link ProjectRequest}
+ * instances, e.g. adding custom dependencies or forcing certain settings based on custom
+ * logic.
+ *
+ * @author Stephane Nicoll
+ */
+interface ProjectRequestPostProcessor {
+
+	/**
+	 * Apply this post processor to the given {@code ProjectRequest} <i>before</i> it
+	 * gets resolved against the specified {@code InitializrMetadata}.
+	 * <p>Consider using this hook to customize basic settings of the {@code request};
+	 * for more advanced logic (in particular with regards to dependencies), consider
+	 * using {@code postProcessAfterResolution}.
+	 * @param request an unresolved {@link ProjectRequest}
+	 * @param metadata the metadata to use to resolve this request
+	 * @see ProjectRequest#resolve(InitializrMetadata)
+	 */
+	void postProcessBeforeResolution(ProjectRequest request, InitializrMetadata metadata);
+
+	/**
+	 * Apply this post processor to the given {@code ProjectRequest} <i>after</i> it has
+	 * been resolved against the specified {@code InitializrMetadata}.
+	 * <p>Dependencies, repositories, bills of materials, default properties and others
+	 * aspects of the request will have been resolved prior to invocation. In particular,
+	 * note that no further validation checks will be performed.
+	 * @param request an resolved {@code ProjectRequest}
+	 * @param metadata the metadata that were used to resolve this request
+	 */
+	void postProcessAfterResolution(ProjectRequest request, InitializrMetadata metadata);
+
+}

initializr-generator/src/main/groovy/io/spring/initializr/generator/ProjectRequestPostProcessorAdapter.groovy

@@ -0,0 +1,21 @@
+package io.spring.initializr.generator
+
+import io.spring.initializr.metadata.InitializrMetadata
+
+/**
+ * An implementation of {@link ProjectRequestPostProcessor} with empty methods allowing
+ * sub-classes to override only the methods they're interested in.
+ *
+ * @author Stephane Nicoll
+ */
+class ProjectRequestPostProcessorAdapter implements ProjectRequestPostProcessor {
+
+	@Override
+	void postProcessBeforeResolution(ProjectRequest request, InitializrMetadata metadata) {
+	}
+
+	@Override
+	void postProcessAfterResolution(ProjectRequest request, InitializrMetadata metadata) {
+	}
+
+}

initializr-generator/src/main/groovy/io/spring/initializr/generator/ProjectRequestResolver.groovy

@@ -0,0 +1,40 @@
+package io.spring.initializr.generator
+
+import io.spring.initializr.metadata.InitializrMetadata
+
+import org.springframework.util.Assert
+
+/**
+ * Resolve {@link ProjectRequest} instances, honoring callback hook points.
+ *
+ * @author Stephane Nicoll
+ */
+class ProjectRequestResolver {
+
+	private final List<ProjectRequestPostProcessor> postProcessors
+
+	ProjectRequestResolver(List<ProjectRequestPostProcessor> postProcessors) {
+		this.postProcessors = new ArrayList<>(postProcessors)
+	}
+
+	ProjectRequest resolve(ProjectRequest request, InitializrMetadata metadata) {
+		Assert.notNull(request, "Request must not be null")
+		applyPostProcessBeforeResolution(request, metadata)
+		request.resolve(metadata)
+		applyPostProcessAfterResolution(request, metadata)
+		request
+	}
+
+	private void applyPostProcessBeforeResolution(ProjectRequest request, InitializrMetadata metadata) {
+		for (ProjectRequestPostProcessor processor : postProcessors) {
+			processor.postProcessBeforeResolution(request, metadata)
+		}
+	}
+
+	private void applyPostProcessAfterResolution(ProjectRequest request, InitializrMetadata metadata) {
+		for (ProjectRequestPostProcessor processor : postProcessors) {
+			processor.postProcessAfterResolution(request, metadata)
+		}
+	}
+
+}

initializr-generator/src/test/groovy/io/spring/initializr/generator/AbstractProjectGeneratorTests.groovy

@@ -57,6 +57,7 @@ abstract class AbstractProjectGeneratorTests {
 				.addDependencyGroup('test', 'security', 'data-jpa', 'aop', 'batch', 'integration').build()
 		applyMetadata(metadata)
 		projectGenerator.eventPublisher = eventPublisher
+		projectGenerator.requestResolver = new ProjectRequestResolver([])
 		projectGenerator.tmpdir = folder.newFolder().absolutePath
 	}
 

initializr-generator/src/test/groovy/io/spring/initializr/generator/ProjectGeneratorTests.groovy

@@ -18,6 +18,7 @@ package io.spring.initializr.generator
 
 import io.spring.initializr.metadata.BillOfMaterials
 import io.spring.initializr.metadata.Dependency
+import io.spring.initializr.metadata.InitializrMetadata
 import io.spring.initializr.test.metadata.InitializrMetadataTestBuilder
 import org.junit.Rule
 import org.junit.Test
@@ -642,6 +643,34 @@ class ProjectGeneratorTests extends AbstractProjectGeneratorTests {
 				.doesNotContain('ignore.property')
 	}
 
+	@Test
+	void versionRangeWithPostProcessor() {
+		Dependency foo = new Dependency(id: 'foo', groupId: 'org.acme', artifactId: 'foo')
+		foo.mappings << new Dependency.Mapping(versionRange: '[1.2.0.RELEASE,1.3.0.M1)', version: '1.0.0')
+		foo.mappings << new Dependency.Mapping(versionRange: '1.3.0.M1', version: '1.2.0')
+		def metadata = InitializrMetadataTestBuilder.withDefaults()
+				.addDependencyGroup('foo', foo).build()
+		applyMetadata(metadata)
+
+		// First without processor, get the correct version
+		def request = createProjectRequest('foo')
+		request.bootVersion = '1.2.5.RELEASE'
+		generateMavenPom(request).hasDependency(
+				new Dependency(id: 'foo', groupId: 'org.acme', artifactId: 'foo', version: '1.0.0'))
+
+		// First after processor that flips Spring Boot version
+		projectGenerator.requestResolver = new ProjectRequestResolver(Collections.singletonList(
+				new ProjectRequestPostProcessorAdapter() {
+					@Override
+					void postProcessBeforeResolution(ProjectRequest r, InitializrMetadata m) {
+						r.bootVersion = '1.3.0.M2'
+					}
+				}
+		))
+		generateMavenPom(request).hasDependency(
+				new Dependency(id: 'foo', groupId: 'org.acme', artifactId: 'foo', version: '1.2.0'))
+	}
+
 	@Test
 	void invalidProjectTypeMavenPom() {
 		def request = createProjectRequest('web')

initializr-generator/src/test/groovy/io/spring/initializr/generator/ProjectRequestResolverTests.groovy

@@ -0,0 +1,86 @@
+package io.spring.initializr.generator
+
+import io.spring.initializr.metadata.InitializrMetadata
+import io.spring.initializr.test.metadata.InitializrMetadataTestBuilder
+import org.junit.Before
+import org.junit.Test
+
+import static org.junit.Assert.assertEquals
+
+/**
+ * Tests for {@link ProjectRequestResolver}.
+ *
+ * @author Stephane Nicoll
+ */
+class ProjectRequestResolverTests {
+
+	def metadata = InitializrMetadataTestBuilder.withDefaults()
+			.addDependencyGroup('test', 'web', 'security', 'data-jpa')
+			.build()
+
+	final List<ProjectRequestPostProcessor> postProcessors = []
+	final GenericProjectRequestPostProcessor processor = new GenericProjectRequestPostProcessor()
+
+	@Before
+	void setup() {
+		this.postProcessors << processor
+	}
+
+	@Test
+	void beforeResolution() {
+		processor.before['javaVersion'] = '1.2'
+		ProjectRequest request = resolve(createMavenProjectRequest(), postProcessors)
+		assertEquals '1.2', request.javaVersion
+		assertEquals '1.2', request.buildProperties.versions['java.version'].call()
+	}
+
+	@Test
+	void afterResolution() {
+		postProcessors << new ProjectRequestPostProcessorAdapter() {
+			@Override
+			void postProcessAfterResolution(ProjectRequest request, InitializrMetadata metadata) {
+				request.buildProperties.maven.clear()
+				request.buildProperties.maven['foo'] = { 'bar' }
+			}
+		}
+		ProjectRequest request = resolve(createMavenProjectRequest(), postProcessors)
+		assertEquals 1, request.buildProperties.maven.size()
+		assertEquals 'bar', request.buildProperties.maven['foo'].call()
+	}
+
+	ProjectRequest resolve(def request, def processors) {
+		new ProjectRequestResolver(processors)
+				.resolve(request, metadata)
+	}
+
+	ProjectRequest createMavenProjectRequest(String... styles) {
+		def request = createProjectRequest(styles)
+		request.type = 'maven-project'
+		request
+	}
+
+	ProjectRequest createProjectRequest(String... styles) {
+		def request = new ProjectRequest()
+		request.initialize(metadata)
+		request.style.addAll Arrays.asList(styles)
+		request
+	}
+
+	static class GenericProjectRequestPostProcessor implements ProjectRequestPostProcessor {
+
+		final Map<String, Object> before = [:]
+		final Map<String, Object> after = [:]
+
+		@Override
+		void postProcessBeforeResolution(ProjectRequest request, InitializrMetadata metadata) {
+			before.forEach { k, v -> request.setProperty(k, v) }
+		}
+
+		@Override
+		void postProcessAfterResolution(ProjectRequest request, InitializrMetadata metadata) {
+			after.forEach { k, v -> request.setProperty(k, v) }
+		}
+
+	}
+
+}