Merge branch 'gh-2313'

spring-boot-tools/spring-boot-configuration-processor/pom.xml

@@ -29,6 +29,10 @@
 			<artifactId>lombok</artifactId>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework</groupId>
+			<artifactId>spring-core</artifactId>
+		</dependency>
 	</dependencies>
 	<build>
 		<plugins>
@@ -36,7 +40,7 @@
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-compiler-plugin</artifactId>
 				<configuration>
-					<!-- Ensure own  annotation processor doens't kick in -->
+					<!-- Ensure own annotation processor doesn't kick in -->
 					<proc>none</proc>
 				</configuration>
 			</plugin>

spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/BuildHandler.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2012-2015 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 org.springframework.boot.configurationprocessor;
+
+import javax.annotation.processing.RoundEnvironment;
+
+import org.springframework.boot.configurationprocessor.metadata.ConfigurationMetadata;
+
+/**
+ * A {@code BuildTracker} tracks a build in which configuration processing has been
+ * performed and is responsible for managing the associated state including the resulting
+ * metadata.
+ *
+ * @author Andy Wilkinson
+ */
+public interface BuildHandler {
+
+	void addGroup(String name, String type, String sourceType, String sourceMethod);
+
+	void addProperty(String prefix, String name, String type, String sourceType,
+			String sourceMethod, String description, Object defaultValue,
+			boolean deprecated);
+
+	void processing(RoundEnvironment environment);
+
+	ConfigurationMetadata produceMetadata();
+
+}

spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/ConfigurationMetadataAnnotationProcessor.java

@@ -16,12 +16,8 @@
 
 package org.springframework.boot.configurationprocessor;
 
-import java.io.File;
-import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
 import java.io.PrintWriter;
 import java.io.StringWriter;
 import java.util.Collections;
@@ -47,14 +43,10 @@ import javax.lang.model.type.TypeKind;
 import javax.lang.model.type.TypeMirror;
 import javax.lang.model.util.Elements;
 import javax.tools.Diagnostic.Kind;
-import javax.tools.FileObject;
-import javax.tools.StandardLocation;
 
 import org.springframework.boot.configurationprocessor.fieldvalues.FieldValuesParser;
 import org.springframework.boot.configurationprocessor.fieldvalues.javac.JavaCompilerFieldValuesParser;
 import org.springframework.boot.configurationprocessor.metadata.ConfigurationMetadata;
-import org.springframework.boot.configurationprocessor.metadata.ItemMetadata;
-import org.springframework.boot.configurationprocessor.metadata.JsonMarshaller;
 
 /**
  * Annotation {@link Processor} that writes meta-data file for
@@ -62,6 +54,7 @@ import org.springframework.boot.configurationprocessor.metadata.JsonMarshaller;
  *
  * @author Stephane Nicoll
  * @author Phillip Webb
+ * @author Kris De Volder
  * @since 1.2.0
  */
 @SupportedAnnotationTypes({ "*" })
@@ -79,11 +72,9 @@ public class ConfigurationMetadataAnnotationProcessor extends AbstractProcessor
 
 	static final String LOMBOK_SETTER_ANNOTATION = "lombok.Setter";
 
-	private static final String RESOURCES_FOLDER = "resources";
+	private MetadataStore metadataStore;
 
-	private static final String CLASSES_FOLDER = "classes";
-
-	private ConfigurationMetadata metadata;
+	private BuildHandler buildHandler;
 
 	private TypeUtils typeUtils;
 
@@ -107,8 +98,9 @@ public class ConfigurationMetadataAnnotationProcessor extends AbstractProcessor
 	@Override
 	public synchronized void init(ProcessingEnvironment env) {
 		super.init(env);
-		this.metadata = new ConfigurationMetadata();
 		this.typeUtils = new TypeUtils(env);
+		this.metadataStore = new MetadataStore(env);
+		this.buildHandler = createBuildHandler(env, this.metadataStore);
 		try {
 			this.fieldValuesParser = new JavaCompilerFieldValuesParser(env);
 		}
@@ -119,16 +111,28 @@ public class ConfigurationMetadataAnnotationProcessor extends AbstractProcessor
 		}
 	}
 
+	private BuildHandler createBuildHandler(ProcessingEnvironment env,
+			MetadataStore metadataStore) {
+		ConfigurationMetadata existingMetadata = metadataStore.readMetadata();
+		if (existingMetadata != null) {
+			return new IncrementalBuildHandler(env, existingMetadata);
+		}
+		else {
+			return new StandardBuildHandler();
+		}
+	}
+
 	@Override
 	public boolean process(Set<? extends TypeElement> annotations,
 			RoundEnvironment roundEnv) {
+		this.buildHandler.processing(roundEnv);
 		Elements elementUtils = this.processingEnv.getElementUtils();
 		for (Element element : roundEnv.getElementsAnnotatedWith(elementUtils
 				.getTypeElement(configurationPropertiesAnnotation()))) {
 			processElement(element);
 		}
 		if (roundEnv.processingOver()) {
-			writeMetaData(this.metadata);
+			writeMetaData();
 		}
 		return false;
 	}
@@ -149,7 +153,7 @@ public class ConfigurationMetadataAnnotationProcessor extends AbstractProcessor
 
 	private void processAnnotatedTypeElement(String prefix, TypeElement element) {
 		String type = this.typeUtils.getType(element);
-		this.metadata.add(ItemMetadata.newGroup(prefix, type, type, null));
+		this.buildHandler.addGroup(prefix, type, type, null);
 		processTypeElement(prefix, element);
 	}
 
@@ -159,10 +163,9 @@ public class ConfigurationMetadataAnnotationProcessor extends AbstractProcessor
 			Element returns = this.processingEnv.getTypeUtils().asElement(
 					element.getReturnType());
 			if (returns instanceof TypeElement) {
-				this.metadata.add(ItemMetadata.newGroup(prefix,
-						this.typeUtils.getType(returns),
+				this.buildHandler.addGroup(prefix, this.typeUtils.getType(returns),
 						this.typeUtils.getType(element.getEnclosingElement()),
-						element.toString()));
+						element.toString());
 				processTypeElement(prefix, (TypeElement) returns);
 			}
 		}
@@ -207,8 +210,8 @@ public class ConfigurationMetadataAnnotationProcessor extends AbstractProcessor
 				boolean deprecated = hasDeprecateAnnotation(getter)
 						|| hasDeprecateAnnotation(setter)
 						|| hasDeprecateAnnotation(element);
-				this.metadata.add(ItemMetadata.newProperty(prefix, name, dataType,
-						sourceType, null, description, defaultValue, deprecated));
+				this.buildHandler.addProperty(prefix, name, dataType, sourceType, null,
+						description, defaultValue, deprecated);
 			}
 		}
 	}
@@ -235,8 +238,8 @@ public class ConfigurationMetadataAnnotationProcessor extends AbstractProcessor
 				Object defaultValue = fieldValues.get(name);
 				boolean deprecated = hasDeprecateAnnotation(field)
 						|| hasDeprecateAnnotation(element);
-				this.metadata.add(ItemMetadata.newProperty(prefix, name, dataType,
-						sourceType, null, description, defaultValue, deprecated));
+				this.buildHandler.addProperty(prefix, name, dataType, sourceType, null,
+						description, defaultValue, deprecated);
 			}
 		}
 	}
@@ -269,9 +272,9 @@ public class ConfigurationMetadataAnnotationProcessor extends AbstractProcessor
 			if (returnType != null && returnType instanceof TypeElement
 					&& annotation == null && isNested) {
 				String nestedPrefix = ConfigurationMetadata.nestedPrefix(prefix, name);
-				this.metadata.add(ItemMetadata.newGroup(nestedPrefix,
+				this.buildHandler.addGroup(nestedPrefix,
 						this.typeUtils.getType(returnType),
-						this.typeUtils.getType(element), getter.toString()));
+						this.typeUtils.getType(element), getter.toString());
 				processTypeElement(nestedPrefix, (TypeElement) returnType);
 			}
 		}
@@ -328,50 +331,33 @@ public class ConfigurationMetadataAnnotationProcessor extends AbstractProcessor
 		return values;
 	}
 
-	protected void writeMetaData(ConfigurationMetadata metadata) {
+	protected ConfigurationMetadata writeMetaData() {
+		ConfigurationMetadata metadata = this.buildHandler.produceMetadata();
 		metadata = mergeAdditionalMetadata(metadata);
 		if (!metadata.getItems().isEmpty()) {
 			try {
-				FileObject resource = this.processingEnv.getFiler().createResource(
-						StandardLocation.CLASS_OUTPUT, "",
-						"META-INF/spring-configuration-metadata.json");
-				OutputStream outputStream = resource.openOutputStream();
-				try {
-					new JsonMarshaller().write(metadata, outputStream);
-				}
-				finally {
-					outputStream.close();
-				}
+				this.metadataStore.writeMetadata(metadata);
 			}
-			catch (Exception ex) {
-				throw new IllegalStateException(ex);
+			catch (IOException ex) {
+				throw new IllegalStateException("Failed to write metadata", ex);
 			}
+			return metadata;
 		}
+		return null;
 	}
 
 	private ConfigurationMetadata mergeAdditionalMetadata(ConfigurationMetadata metadata) {
 		try {
-			InputStream inputStream = getAdditionalMetadata();
-			try {
-				ConfigurationMetadata merged = new ConfigurationMetadata(metadata);
-				try {
-					merged.addAll(new JsonMarshaller().read(inputStream));
-				}
-				catch (Exception ex) {
-					throw new IllegalStateException(ex);
-				}
-				return merged;
-			}
-			finally {
-				inputStream.close();
-			}
+			ConfigurationMetadata merged = new ConfigurationMetadata(metadata);
+			merged.addAll(this.metadataStore.readAdditionalMetadata());
+			return merged;
 		}
 		catch (FileNotFoundException ex) {
 			// No additional metadata
 			return metadata;
 		}
 		catch (Exception ex) {
-			logWarning("Unable to merge additional-spring-configuration-metadata.json");
+			logWarning("Unable to merge additional metadata");
 			logWarning(getStackTrace(ex));
 			return metadata;
 		}
@@ -383,26 +369,6 @@ public class ConfigurationMetadataAnnotationProcessor extends AbstractProcessor
 		return writer.toString();
 	}
 
-	private InputStream getAdditionalMetadata() throws IOException {
-		// Most build systems will have copied the file to the class output location
-		FileObject fileObject = this.processingEnv.getFiler().createResource(
-				StandardLocation.CLASS_OUTPUT, "",
-				"META-INF/additional-spring-configuration-metadata.json");
-		File file = new File(fileObject.toUri());
-		if (!file.exists()) {
-			// Gradle keeps things separate
-			String path = file.getPath();
-			int index = path.lastIndexOf(CLASSES_FOLDER);
-			if (index >= 0) {
-				path = path.substring(0, index) + RESOURCES_FOLDER
-						+ path.substring(index + CLASSES_FOLDER.length());
-				file = new File(path);
-			}
-		}
-		return (file.exists() ? new FileInputStream(file) : fileObject.toUri().toURL()
-				.openStream());
-	}
-
 	private void logWarning(String msg) {
 		this.processingEnv.getMessager().printMessage(Kind.WARNING, msg);
 	}

spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/IncrementalBuildHandler.java

@@ -0,0 +1,109 @@
+/*
+ * Copyright 2012-2014 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 org.springframework.boot.configurationprocessor;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import javax.annotation.processing.ProcessingEnvironment;
+import javax.annotation.processing.RoundEnvironment;
+import javax.lang.model.element.Element;
+import javax.lang.model.element.TypeElement;
+
+import org.springframework.boot.configurationprocessor.metadata.ConfigurationMetadata;
+import org.springframework.boot.configurationprocessor.metadata.ItemMetadata;
+
+/**
+ * {@code BuildHandler} that provides incremental build support by merging the metadata
+ * from the current incremental build with any existing metadata.
+ *
+ * @author Andy Wilkinson
+ * @author Kris De Volder
+ * @since 1.2.2
+ */
+public class IncrementalBuildHandler extends StandardBuildHandler {
+
+	private final Set<String> processedSourceTypes = new HashSet<String>();
+
+	private final ProcessingEnvironment processingEnvironment;
+
+	private final ConfigurationMetadata existingMetadata;
+
+	private final TypeUtils typeUtils;
+
+	/**
+	 * Creates a new {@code IncrementalBuildTracker} that will merge the metadata produced
+	 * by an incremental build with the given {@code existingMetadata}.
+	 *
+	 * @param processingEnvironment The processing environment of the build
+	 * @param existingMetadata The existing metadata
+	 */
+	public IncrementalBuildHandler(ProcessingEnvironment processingEnvironment,
+			ConfigurationMetadata existingMetadata) {
+		this.existingMetadata = existingMetadata;
+		this.processingEnvironment = processingEnvironment;
+		this.typeUtils = new TypeUtils(processingEnvironment);
+	}
+
+	@Override
+	public void processing(RoundEnvironment environment) {
+		for (Element element : environment.getRootElements()) {
+			markAsProcessed(element);
+		}
+	}
+
+	@Override
+	public ConfigurationMetadata produceMetadata() {
+		ConfigurationMetadata metadata = super.produceMetadata();
+		mergeExistingMetadata(metadata);
+		return metadata;
+	}
+
+	private void markAsProcessed(Element element) {
+		if (element instanceof TypeElement) {
+			this.processedSourceTypes.add(this.typeUtils.getType(element));
+		}
+	}
+
+	private void mergeExistingMetadata(ConfigurationMetadata metadata) {
+		List<ItemMetadata> items = this.existingMetadata.getItems();
+		for (ItemMetadata oldItem : items) {
+			if (shouldBeMerged(oldItem)) {
+				metadata.add(oldItem);
+			}
+		}
+	}
+
+	private boolean shouldBeMerged(ItemMetadata itemMetadata) {
+		String sourceType = itemMetadata.getSourceType();
+		if (sourceType == null || deletedInCurrentBuild(sourceType)
+				|| processedInCurrentBuild(sourceType)) {
+			return false;
+		}
+		return true;
+	}
+
+	private boolean deletedInCurrentBuild(String sourceType) {
+		return this.processingEnvironment.getElementUtils().getTypeElement(sourceType) == null;
+	}
+
+	private boolean processedInCurrentBuild(String sourceType) {
+		return this.processedSourceTypes.contains(sourceType);
+	}
+
+}

spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/MetadataStore.java

@@ -0,0 +1,122 @@
+/*
+ * Copyright 2012-2015 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 org.springframework.boot.configurationprocessor;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import javax.annotation.processing.ProcessingEnvironment;
+import javax.tools.FileObject;
+import javax.tools.StandardLocation;
+
+import org.springframework.boot.configurationprocessor.metadata.ConfigurationMetadata;
+import org.springframework.boot.configurationprocessor.metadata.JsonMarshaller;
+
+/**
+ * A {@code MetadataStore} is responsible for the storage of metadata on the filesystem
+ *
+ * @author Andy Wilkinson
+ * @since 1.2.2
+ */
+public class MetadataStore {
+
+	static final String METADATA_PATH = "META-INF/spring-configuration-metadata.json";
+
+	private static final String ADDITIONAL_METADATA_PATH = "META-INF/additional-spring-configuration-metadata.json";
+
+	private static final String RESOURCES_FOLDER = "resources";
+
+	private static final String CLASSES_FOLDER = "classes";
+
+	private final ProcessingEnvironment environment;
+
+	public MetadataStore(ProcessingEnvironment environment) {
+		this.environment = environment;
+	}
+
+	public ConfigurationMetadata readMetadata() {
+		try {
+			return readMetadata(getMetadataResource().openInputStream());
+		}
+		catch (IOException ex) {
+			return null;
+		}
+	}
+
+	public void writeMetadata(ConfigurationMetadata metadata) throws IOException {
+		if (!metadata.getItems().isEmpty()) {
+			OutputStream outputStream = createMetadataResource().openOutputStream();
+			try {
+				new JsonMarshaller().write(metadata, outputStream);
+			}
+			finally {
+				outputStream.close();
+			}
+		}
+	}
+
+	public ConfigurationMetadata readAdditionalMetadata() throws IOException {
+		return readMetadata(getAdditionalMetadataStream());
+	}
+
+	private ConfigurationMetadata readMetadata(InputStream in) throws IOException {
+		try {
+			return new JsonMarshaller().read(in);
+		}
+		catch (IOException ex) {
+			return null;
+		}
+		finally {
+			in.close();
+		}
+	}
+
+	private FileObject getMetadataResource() throws IOException {
+		FileObject resource = this.environment.getFiler().getResource(
+				StandardLocation.CLASS_OUTPUT, "", METADATA_PATH);
+		return resource;
+	}
+
+	private FileObject createMetadataResource() throws IOException {
+		FileObject resource = this.environment.getFiler().createResource(
+				StandardLocation.CLASS_OUTPUT, "", METADATA_PATH);
+		return resource;
+	}
+
+	private InputStream getAdditionalMetadataStream() throws IOException {
+		// Most build systems will have copied the file to the class output location
+		FileObject fileObject = this.environment.getFiler().getResource(
+				StandardLocation.CLASS_OUTPUT, "", ADDITIONAL_METADATA_PATH);
+		File file = new File(fileObject.toUri());
+		if (!file.exists()) {
+			// Gradle keeps things separate
+			String path = file.getPath();
+			int index = path.lastIndexOf(CLASSES_FOLDER);
+			if (index >= 0) {
+				path = path.substring(0, index) + RESOURCES_FOLDER
+						+ path.substring(index + CLASSES_FOLDER.length());
+				file = new File(path);
+			}
+		}
+		return (file.exists() ? new FileInputStream(file) : fileObject.toUri().toURL()
+				.openStream());
+	}
+
+}

spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/StandardBuildHandler.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2012-2014 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 org.springframework.boot.configurationprocessor;
+
+import javax.annotation.processing.RoundEnvironment;
+
+import org.springframework.boot.configurationprocessor.metadata.ConfigurationMetadata;
+import org.springframework.boot.configurationprocessor.metadata.ItemMetadata;
+
+/**
+ * Standard implementation of {@code BuildHandler} that handles the state of a single
+ * build.
+ *
+ * @author Andy Wilkinson
+ * @since 1.2.2
+ */
+public class StandardBuildHandler implements BuildHandler {
+
+	private final ConfigurationMetadata metadata = new ConfigurationMetadata();
+
+	@Override
+	public void addGroup(String name, String type, String sourceType, String sourceMethod) {
+		this.metadata.add(ItemMetadata.newGroup(name, type, sourceType, sourceMethod));
+	}
+
+	@Override
+	public void addProperty(String prefix, String name, String type, String sourceType,
+			String sourceMethod, String description, Object defaultValue,
+			boolean deprecated) {
+		this.metadata.add(ItemMetadata.newProperty(prefix, name, type, sourceType,
+				sourceMethod, description, defaultValue, deprecated));
+	}
+
+	@Override
+	public void processing(RoundEnvironment environment) {
+
+	}
+
+	@Override
+	public ConfigurationMetadata produceMetadata() {
+		return this.metadata;
+	}
+
+}

spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationprocessor/ConfigurationMetadataAnnotationProcessorTests.java

@@ -17,14 +17,9 @@
 package org.springframework.boot.configurationprocessor;
 
 import java.io.File;
-import java.io.FileInputStream;
 import java.io.FileWriter;
 import java.io.IOException;
 
-import javax.annotation.processing.SupportedAnnotationTypes;
-import javax.annotation.processing.SupportedSourceVersion;
-import javax.lang.model.SourceVersion;
-
 import org.json.JSONArray;
 import org.json.JSONObject;
 import org.junit.Before;
@@ -32,7 +27,9 @@ import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
 import org.springframework.boot.configurationprocessor.metadata.ConfigurationMetadata;
-import org.springframework.boot.configurationprocessor.metadata.JsonMarshaller;
+import org.springframework.boot.configurationsample.incremental.BarProperties;
+import org.springframework.boot.configurationsample.incremental.FooProperties;
+import org.springframework.boot.configurationsample.incremental.RenamedBarProperties;
 import org.springframework.boot.configurationsample.lombok.LombokExplicitProperties;
 import org.springframework.boot.configurationsample.lombok.LombokSimpleDataProperties;
 import org.springframework.boot.configurationsample.lombok.LombokSimpleProperties;
@@ -57,9 +54,12 @@ import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.not;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
 import static org.springframework.boot.configurationprocessor.ConfigurationMetadataMatchers.containsGroup;
 import static org.springframework.boot.configurationprocessor.ConfigurationMetadataMatchers.containsProperty;
+import static org.springframework.boot.configurationprocessor.MetadataStore.METADATA_PATH;
 
 /**
  * Tests for {@link ConfigurationMetadataAnnotationProcessor}.
@@ -67,6 +67,7 @@ import static org.springframework.boot.configurationprocessor.ConfigurationMetad
  * @author Stephane Nicoll
  * @author Phillip Webb
  * @author Andy Wilkinson
+ * @author Kris De Volder
  */
 public class ConfigurationMetadataAnnotationProcessorTests {
 
@@ -349,7 +350,80 @@ public class ConfigurationMetadataAnnotationProcessorTests {
 		assertThat(metadata,
 				containsProperty("foo", String.class)
 						.fromSource(AdditionalMetadata.class));
+	}
 
+	@Test
+	public void incrementalBuild() throws Exception {
+		TestProject project = new TestProject(this.temporaryFolder, FooProperties.class,
+				BarProperties.class);
+		assertFalse(project.getOutputFile(METADATA_PATH).exists());
+
+		ConfigurationMetadata metadata = project.fullBuild();
+		assertTrue(project.getOutputFile(METADATA_PATH).exists());
+
+		assertThat(metadata,
+				containsProperty("foo.counter").fromSource(FooProperties.class));
+		assertThat(metadata,
+				containsProperty("bar.counter").fromSource(BarProperties.class));
+
+		metadata = project.incrementalBuild(BarProperties.class);
+
+		assertThat(metadata,
+				containsProperty("foo.counter").fromSource(FooProperties.class));
+		assertThat(metadata,
+				containsProperty("bar.counter").fromSource(BarProperties.class));
+
+		project.addSourceCode(BarProperties.class,
+				BarProperties.class.getResourceAsStream("BarProperties.snippet"));
+		metadata = project.incrementalBuild(BarProperties.class);
+		assertThat(metadata, containsProperty("bar.extra"));
+		assertThat(metadata, containsProperty("foo.counter"));
+		assertThat(metadata, containsProperty("bar.counter"));
+
+		project.revert(BarProperties.class);
+		metadata = project.incrementalBuild(BarProperties.class);
+		assertThat(metadata, not(containsProperty("bar.extra")));
+		assertThat(metadata, containsProperty("foo.counter"));
+		assertThat(metadata, containsProperty("bar.counter"));
+	}
+
+	@Test
+	public void incremenalBuildAnnotationRemoved() throws Exception {
+		TestProject project = new TestProject(this.temporaryFolder, FooProperties.class,
+				BarProperties.class);
+		ConfigurationMetadata metadata = project.fullBuild();
+		assertThat(metadata, containsProperty("foo.counter"));
+		assertThat(metadata, containsProperty("bar.counter"));
+
+		project.replaceText(BarProperties.class, "@ConfigurationProperties",
+				"//@ConfigurationProperties");
+		metadata = project.incrementalBuild(BarProperties.class);
+		assertThat(metadata, containsProperty("foo.counter"));
+		assertThat(metadata, not(containsProperty("bar.counter")));
+	}
+
+	@Test
+	public void incremenalBuildTypeRenamed() throws Exception {
+		TestProject project = new TestProject(this.temporaryFolder, FooProperties.class,
+				BarProperties.class);
+		ConfigurationMetadata metadata = project.fullBuild();
+		assertThat(metadata,
+				containsProperty("foo.counter").fromSource(FooProperties.class));
+		assertThat(metadata,
+				containsProperty("bar.counter").fromSource(BarProperties.class));
+		assertThat(metadata,
+				not(containsProperty("bar.counter")
+						.fromSource(RenamedBarProperties.class)));
+
+		project.delete(BarProperties.class);
+		project.add(RenamedBarProperties.class);
+		metadata = project.incrementalBuild(RenamedBarProperties.class);
+		assertThat(metadata,
+				containsProperty("foo.counter").fromSource(FooProperties.class));
+		assertThat(metadata,
+				not(containsProperty("bar.counter").fromSource(BarProperties.class)));
+		assertThat(metadata,
+				containsProperty("bar.counter").fromSource(RenamedBarProperties.class));
 	}
 
 	private void assertSimpleLombokProperties(ConfigurationMetadata metadata,
@@ -368,59 +442,12 @@ public class ConfigurationMetadataAnnotationProcessorTests {
 	}
 
 	private ConfigurationMetadata compile(Class<?>... types) throws IOException {
-		TestConfigurationMetadataAnnotationProcessor processor = new TestConfigurationMetadataAnnotationProcessor();
+		TestConfigurationMetadataAnnotationProcessor processor = new TestConfigurationMetadataAnnotationProcessor(
+				this.compiler.getOutputLocation());
 		this.compiler.getTask(types).call(processor);
 		return processor.getMetadata();
 	}
 
-	@SupportedAnnotationTypes({ "*" })
-	@SupportedSourceVersion(SourceVersion.RELEASE_6)
-	private class TestConfigurationMetadataAnnotationProcessor extends
-			ConfigurationMetadataAnnotationProcessor {
-
-		static final String CONFIGURATION_PROPERTIES_ANNOTATION = "org.springframework.boot.configurationsample.ConfigurationProperties";
-
-		static final String NESTED_CONFIGURATION_PROPERTY_ANNOTATION = "org.springframework.boot.configurationsample.NestedConfigurationProperty";
-
-		private ConfigurationMetadata metadata;
-
-		@Override
-		protected String configurationPropertiesAnnotation() {
-			return CONFIGURATION_PROPERTIES_ANNOTATION;
-		}
-
-		@Override
-		protected String nestedConfigurationPropertyAnnotation() {
-			return NESTED_CONFIGURATION_PROPERTY_ANNOTATION;
-		}
-
-		@Override
-		protected void writeMetaData(ConfigurationMetadata metadata) {
-			super.writeMetaData(metadata);
-			try {
-				File metadataFile = new File(
-						ConfigurationMetadataAnnotationProcessorTests.this.compiler
-								.getOutputLocation(),
-						"META-INF/spring-configuration-metadata.json");
-				if (metadataFile.isFile()) {
-					this.metadata = new JsonMarshaller().read(new FileInputStream(
-							metadataFile));
-				}
-				else {
-					this.metadata = metadata;
-				}
-			}
-			catch (IOException e) {
-				throw new RuntimeException("Failed to read metadata from disk", e);
-			}
-		}
-
-		public ConfigurationMetadata getMetadata() {
-			return this.metadata;
-		}
-
-	}
-
 	private static class AdditionalMetadata {
 
 	}

spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationprocessor/TestCompiler.java

@@ -19,6 +19,7 @@ package org.springframework.boot.configurationprocessor;
 import java.io.File;
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.Collection;
 
 import javax.annotation.processing.Processor;
 import javax.tools.JavaCompiler;
@@ -39,6 +40,8 @@ import org.junit.rules.TemporaryFolder;
  */
 public class TestCompiler {
 
+	public static final File ORIGINAL_SOURCE_FOLDER = new File("src/test/java");
+
 	private final JavaCompiler compiler;
 
 	private final StandardJavaFileManager fileManager;
@@ -59,8 +62,18 @@ public class TestCompiler {
 		this.fileManager.setLocation(StandardLocation.SOURCE_OUTPUT, temp);
 	}
 
+	public TestCompilationTask getTask(Collection<File> sourceFiles) {
+		Iterable<? extends JavaFileObject> javaFileObjects = this.fileManager
+				.getJavaFileObjectsFromFiles(sourceFiles);
+		return getTask(javaFileObjects);
+	}
+
 	public TestCompilationTask getTask(Class<?>... types) {
 		Iterable<? extends JavaFileObject> javaFileObjects = getJavaFileObjects(types);
+		return getTask(javaFileObjects);
+	}
+
+	private TestCompilationTask getTask(Iterable<? extends JavaFileObject> javaFileObjects) {
 		return new TestCompilationTask(this.compiler.getTask(null, this.fileManager,
 				null, null, null, javaFileObjects));
 	}
@@ -77,8 +90,16 @@ public class TestCompiler {
 		return this.fileManager.getJavaFileObjects(files);
 	}
 
-	private File getFile(Class<?> type) {
-		return new File("src/test/java/" + type.getName().replace(".", "/") + ".java");
+	protected File getFile(Class<?> type) {
+		return new File(getSourceFolder(), sourcePathFor(type));
+	}
+
+	public static String sourcePathFor(Class<?> type) {
+		return type.getName().replace(".", "/") + ".java";
+	}
+
+	protected File getSourceFolder() {
+		return ORIGINAL_SOURCE_FOLDER;
 	}
 
 	/**

spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationprocessor/TestConfigurationMetadataAnnotationProcessor.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2012-2015 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 org.springframework.boot.configurationprocessor;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+
+import javax.annotation.processing.SupportedAnnotationTypes;
+import javax.annotation.processing.SupportedSourceVersion;
+import javax.lang.model.SourceVersion;
+
+import org.springframework.boot.configurationprocessor.metadata.ConfigurationMetadata;
+import org.springframework.boot.configurationprocessor.metadata.JsonMarshaller;
+
+/**
+ * @author Stephane Nicoll
+ * @author Phillip Webb
+ * @author Andy Wilkinson
+ * @author Kris De Volder
+ */
+@SupportedAnnotationTypes({ "*" })
+@SupportedSourceVersion(SourceVersion.RELEASE_6)
+public class TestConfigurationMetadataAnnotationProcessor extends
+		ConfigurationMetadataAnnotationProcessor {
+
+	static final String CONFIGURATION_PROPERTIES_ANNOTATION = "org.springframework.boot.configurationsample.ConfigurationProperties";
+
+	static final String NESTED_CONFIGURATION_PROPERTY_ANNOTATION = "org.springframework.boot.configurationsample.NestedConfigurationProperty";
+
+	private ConfigurationMetadata metadata;
+
+	private final File outputLocation;
+
+	public TestConfigurationMetadataAnnotationProcessor(File outputLocation) {
+		this.outputLocation = outputLocation;
+	}
+
+	@Override
+	protected String configurationPropertiesAnnotation() {
+		return CONFIGURATION_PROPERTIES_ANNOTATION;
+	}
+
+	@Override
+	protected String nestedConfigurationPropertyAnnotation() {
+		return NESTED_CONFIGURATION_PROPERTY_ANNOTATION;
+	}
+
+	@Override
+	protected ConfigurationMetadata writeMetaData() {
+		super.writeMetaData();
+		try {
+			File metadataFile = new File(this.outputLocation,
+					"META-INF/spring-configuration-metadata.json");
+			if (metadataFile.isFile()) {
+				this.metadata = new JsonMarshaller().read(new FileInputStream(
+						metadataFile));
+			}
+			else {
+				this.metadata = new ConfigurationMetadata();
+			}
+			return this.metadata;
+		}
+		catch (IOException e) {
+			throw new RuntimeException("Failed to read metadata from disk", e);
+		}
+	}
+
+	public ConfigurationMetadata getMetadata() {
+		return this.metadata;
+	}
+
+}

spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationprocessor/TestProject.java

@@ -0,0 +1,193 @@
+/*
+ * Copyright 2012-2015 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 org.springframework.boot.configurationprocessor;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.StringReader;
+import java.io.UnsupportedEncodingException;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.LinkedHashSet;
+import java.util.Set;
+
+import org.junit.Assert;
+import org.junit.rules.TemporaryFolder;
+import org.springframework.boot.configurationprocessor.TestCompiler.TestCompilationTask;
+import org.springframework.boot.configurationprocessor.metadata.ConfigurationMetadata;
+import org.springframework.boot.configurationsample.ConfigurationProperties;
+import org.springframework.boot.configurationsample.NestedConfigurationProperty;
+import org.springframework.util.FileCopyUtils;
+import org.springframework.util.FileSystemUtils;
+
+import static org.springframework.boot.configurationprocessor.TestCompiler.ORIGINAL_SOURCE_FOLDER;
+import static org.springframework.boot.configurationprocessor.TestCompiler.sourcePathFor;
+
+/**
+ * A TestProject contains a copy of a subset of test sample code.
+ * <p>
+ * Why a copy? Because when doing incremental build testing, we need to make modifications
+ * to the contents of the 'test project'. But we don't want to actually modify the
+ * original content itself.
+ *
+ * @author Kris De Volder
+ */
+public class TestProject {
+
+	private static final Class<?>[] ALWAYS_INCLUDE = { ConfigurationProperties.class,
+			NestedConfigurationProperty.class };
+
+	/**
+	 * Contains copies of the original source so we can modify it safely to test
+	 * incremental builds.
+	 */
+	private File sourceFolder;
+	private TestCompiler compiler;
+
+	private Set<File> sourceFiles = new LinkedHashSet<File>();
+
+	public TestProject(TemporaryFolder tempFolder, Class<?>... classes)
+			throws IOException {
+		this.sourceFolder = tempFolder.newFolder();
+		this.compiler = new TestCompiler(tempFolder) {
+			@Override
+			protected File getSourceFolder() {
+				return TestProject.this.sourceFolder;
+			}
+		};
+		Set<Class<?>> contents = new HashSet<Class<?>>(Arrays.asList(classes));
+		contents.addAll(Arrays.asList(ALWAYS_INCLUDE));
+		copySources(contents);
+	}
+
+	private void copySources(Set<Class<?>> contents) throws IOException {
+		for (Class<?> klass : contents) {
+			copySources(klass);
+		}
+	}
+
+	private void copySources(Class<?> klass) throws IOException {
+		File original = getOriginalSourceFile(klass);
+		File target = getSourceFile(klass);
+		target.getParentFile().mkdirs();
+		FileCopyUtils.copy(original, target);
+		this.sourceFiles.add(target);
+	}
+
+	public File getSourceFile(Class<?> klass) {
+		return new File(this.sourceFolder, sourcePathFor(klass));
+	}
+
+	public ConfigurationMetadata fullBuild() {
+		TestConfigurationMetadataAnnotationProcessor processor = new TestConfigurationMetadataAnnotationProcessor(
+				this.compiler.getOutputLocation());
+		TestCompilationTask task = this.compiler.getTask(this.sourceFiles);
+		deleteFolderContents(this.compiler.getOutputLocation());
+		task.call(processor);
+		return processor.getMetadata();
+	}
+
+	public ConfigurationMetadata incrementalBuild(Class<?>... toRecompile) {
+		TestConfigurationMetadataAnnotationProcessor processor = new TestConfigurationMetadataAnnotationProcessor(
+				this.compiler.getOutputLocation());
+		TestCompilationTask task = this.compiler.getTask(toRecompile);
+		task.call(processor);
+		return processor.getMetadata();
+	}
+
+	private void deleteFolderContents(File outputFolder) {
+		FileSystemUtils.deleteRecursively(outputFolder);
+		outputFolder.mkdirs();
+	}
+
+	/**
+	 * Retrieve File relative to project's output folder.
+	 */
+	public File getOutputFile(String relativePath) {
+		Assert.assertFalse(new File(relativePath).isAbsolute());
+		return new File(this.compiler.getOutputLocation(), relativePath);
+	}
+
+	/**
+	 * Add source code at the end of file, just before last '}'
+	 */
+	public void addSourceCode(Class<?> target, InputStream snippetStream)
+			throws Exception {
+		File targetFile = getSourceFile(target);
+		String contents = getContents(targetFile);
+		int insertAt = contents.lastIndexOf('}');
+		String additionalSource = FileCopyUtils.copyToString(new InputStreamReader(
+				snippetStream));
+		contents = contents.substring(0, insertAt) + additionalSource
+				+ contents.substring(insertAt);
+		putContents(targetFile, contents);
+	}
+
+	/**
+	 * Delete source file for given class from project.
+	 */
+	public void delete(Class<?> klass) {
+		File target = getSourceFile(klass);
+		target.delete();
+		this.sourceFiles.remove(target);
+	}
+
+	/**
+	 * Restore source code of given class to its original contents.
+	 */
+	public void revert(Class<?> klass) throws IOException {
+		Assert.assertTrue(getSourceFile(klass).exists());
+		copySources(klass);
+	}
+
+	/**
+	 * Add source code of given class to this project.
+	 */
+	public void add(Class<?> klass) throws IOException {
+		Assert.assertFalse(getSourceFile(klass).exists());
+		copySources(klass);
+	}
+
+	public void replaceText(Class<?> klass, String find, String replace) throws Exception {
+		File target = getSourceFile(klass);
+		String contents = getContents(target);
+		contents = contents.replace(find, replace);
+		putContents(target, contents);
+	}
+
+	/**
+	 * Find the 'original' source code for given test class. Clients or subclasses should
+	 * have no need to know about these. They should work only with the copied source
+	 * code.
+	 */
+	private File getOriginalSourceFile(Class<?> klass) {
+		return new File(ORIGINAL_SOURCE_FOLDER, sourcePathFor(klass));
+	}
+
+	private static void putContents(File targetFile, String contents)
+			throws FileNotFoundException, IOException, UnsupportedEncodingException {
+		FileCopyUtils.copy(new StringReader(contents), new FileWriter(targetFile));
+	}
+
+	private static String getContents(File file) throws Exception {
+		return FileCopyUtils.copyToString(new FileReader(file));
+	}
+}

spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationsample/incremental/BarProperties.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2012-2015 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 org.springframework.boot.configurationsample.incremental;
+
+import org.springframework.boot.configurationsample.ConfigurationProperties;
+
+@ConfigurationProperties("bar")
+public class BarProperties {
+
+	private String name;
+
+	private String description;
+
+	/**
+	 * A nice counter description.
+	 */
+	private Integer counter = 0;
+
+	public String getName() {
+		return this.name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public String getDescription() {
+		return this.description;
+	}
+
+	public void setDescription(String description) {
+		this.description = description;
+	}
+
+	public Integer getCounter() {
+		return this.counter;
+	}
+
+	public void setCounter(Integer counter) {
+		this.counter = counter;
+	}
+}

spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationsample/incremental/FooProperties.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2012-2015 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 org.springframework.boot.configurationsample.incremental;
+
+import org.springframework.boot.configurationsample.ConfigurationProperties;
+
+@ConfigurationProperties("foo")
+public class FooProperties {
+
+	private String name;
+
+	private String description;
+
+	/**
+	 * A nice counter description.
+	 */
+	private Integer counter = 0;
+
+	public String getName() {
+		return this.name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public String getDescription() {
+		return this.description;
+	}
+
+	public void setDescription(String description) {
+		this.description = description;
+	}
+
+	public Integer getCounter() {
+		return this.counter;
+	}
+
+	public void setCounter(Integer counter) {
+		this.counter = counter;
+	}
+
+}

spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationsample/incremental/RenamedBarProperties.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2012-2015 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 org.springframework.boot.configurationsample.incremental;
+
+import org.springframework.boot.configurationsample.ConfigurationProperties;
+
+@ConfigurationProperties("bar")
+public class RenamedBarProperties {
+
+	private String name;
+
+	private String description;
+
+	/**
+	 * A nice counter description.
+	 */
+	private Integer counter = 0;
+
+	public String getName() {
+		return this.name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public String getDescription() {
+		return this.description;
+	}
+
+	public void setDescription(String description) {
+		this.description = description;
+	}
+
+	public Integer getCounter() {
+		return this.counter;
+	}
+
+	public void setCounter(Integer counter) {
+		this.counter = counter;
+	}
+}

spring-boot-tools/spring-boot-configuration-processor/src/test/resources/org/springframework/boot/configurationsample/incremental/BarProperties.snippet

@@ -0,0 +1,9 @@
+	private String extra;
+
+	public String getExtra() {
+		return extra;
+	}
+
+	public void setExtra(String extra) {
+		this.extra = extra;
+	}