Add easy way to consume configuration metadata

Add a companion module that IDE developers can use to read configuration
metadata from multiple sources into a single repository.

ConfigurationMetadataRepository provides access to groups and items as
well as an harmonized view on "sources" (that is the POJOs that have
contributed to a given group).

Closes gh-1970

spring-boot-dependencies/pom.xml

@@ -159,6 +159,11 @@
 				<artifactId>spring-boot-autoconfigure</artifactId>
 				<version>1.2.0.BUILD-SNAPSHOT</version>
 			</dependency>
+			<dependency>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-configuration-metadata</artifactId>
+				<version>1.2.0.BUILD-SNAPSHOT</version>
+			</dependency>
 			<dependency>
 				<groupId>org.springframework.boot</groupId>
 				<artifactId>spring-boot-configuration-processor</artifactId>

spring-boot-tools/pom.xml

@@ -20,6 +20,7 @@
 		<main.basedir>${basedir}/..</main.basedir>
 	</properties>
 	<modules>
+		<module>spring-boot-configuration-metadata</module>
 		<module>spring-boot-configuration-processor</module>
 		<module>spring-boot-dependency-tools</module>
 		<module>spring-boot-loader</module>

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

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-tools</artifactId>
+		<version>1.2.0.BUILD-SNAPSHOT</version>
+	</parent>
+	<artifactId>spring-boot-configuration-metadata</artifactId>
+	<name>Spring Boot Configuration Metadata</name>
+	<description>Spring Boot Configuration Metadata</description>
+	<url>http://projects.spring.io/spring-boot/</url>
+	<organization>
+		<name>Pivotal Software, Inc.</name>
+		<url>http://www.spring.io</url>
+	</organization>
+	<properties>
+		<main.basedir>${basedir}/../..</main.basedir>
+	</properties>
+	<dependencies>
+		<dependency>
+			<groupId>org.json</groupId>
+			<artifactId>json</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework</groupId>
+			<artifactId>spring-core</artifactId>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+</project>

spring-boot-tools/spring-boot-configuration-metadata/src/main/java/org/springframework/configurationmetadata/ConfigurationMetadataGroup.java

@@ -0,0 +1,68 @@
+/*
+ * 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.configurationmetadata;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Gather a collection of {@link ConfigurationMetadataProperty} that are sharing
+ * a common prefix.
+ *
+ * @author Stephane Nicoll
+ * @since 1.2.0
+ */
+public class ConfigurationMetadataGroup {
+
+	private final String id;
+
+	private final Map<String, ConfigurationMetadataSource> sources =
+			new HashMap<String, ConfigurationMetadataSource>();
+
+	private final Map<String, ConfigurationMetadataProperty> properties =
+			new HashMap<String, ConfigurationMetadataProperty>();
+
+	public ConfigurationMetadataGroup(String id) {
+		this.id = id;
+	}
+
+	/**
+	 * Return the id of the group.
+	 */
+	public String getId() {
+		return this.id;
+	}
+
+	/**
+	 * Return the {@link ConfigurationMetadataSource sources} defining
+	 * the properties of this group.
+	 */
+	public Map<String, ConfigurationMetadataSource> getSources() {
+		return this.sources;
+	}
+
+	/**
+	 * Return the {@link ConfigurationMetadataProperty properties} defined in this group.
+	 * <p>A property may appear more than once for a given source, potentially with conflicting
+	 * type or documentation. This is a "merged" view of the properties of this group.
+	 * @see ConfigurationMetadataSource#getProperties()
+	 */
+	public Map<String, ConfigurationMetadataProperty> getProperties() {
+		return this.properties;
+	}
+
+}

spring-boot-tools/spring-boot-configuration-metadata/src/main/java/org/springframework/configurationmetadata/ConfigurationMetadataItem.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.configurationmetadata;
+
+/**
+ * An extension of {@link ConfigurationMetadataProperty} that provides the
+ * a reference to its source.
+ *
+ * @author Stephane Nicoll
+ * @since 1.2.0
+ */
+class ConfigurationMetadataItem extends ConfigurationMetadataProperty {
+
+	private String sourceType;
+
+	private String sourceMethod;
+
+	/**
+	 * The class name of the source that contributed this property. For example, if the property
+	 * was from a class annotated with {@code @ConfigurationProperties} this attribute would
+	 * contain the fully qualified name of that class.
+	 */
+	public String getSourceType() {
+		return this.sourceType;
+	}
+
+	public void setSourceType(String sourceType) {
+		this.sourceType = sourceType;
+	}
+
+	/**
+	 * The full name of the method (include parenthesis and argument types) that contributed this
+	 * property. For example, the name of a getter in a {@code @ConfigurationProperties} annotated
+	 * class.
+	 */
+	public String getSourceMethod() {
+		return this.sourceMethod;
+	}
+
+	public void setSourceMethod(String sourceMethod) {
+		this.sourceMethod = sourceMethod;
+	}
+
+}

spring-boot-tools/spring-boot-configuration-metadata/src/main/java/org/springframework/configurationmetadata/ConfigurationMetadataProperty.java

@@ -0,0 +1,113 @@
+/*
+ * 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.configurationmetadata;
+
+/**
+ * Define a configuration item.
+ *
+ * @author Stephane Nicoll
+ * @since 1.2.0
+ */
+public class ConfigurationMetadataProperty {
+
+	private String id;
+
+	private String name;
+
+	private String type;
+
+	private String description;
+
+	private Object defaultValue;
+
+	private boolean deprecated;
+
+	/**
+	 * The full identifier of the property, in lowercase dashed form (e.g. my.group.simple-property)
+	 */
+	public String getId() {
+		return this.id;
+	}
+
+	public void setId(String id) {
+		this.id = id;
+	}
+
+	/**
+	 * The name of the property, in lowercase dashed form (e.g. simple-property). If this item
+	 * does not belong to any group, the id is returned.
+	 */
+	public String getName() {
+		return this.name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	/**
+	 * The class name of the data type of the property. For example, {@code java.lang.String}.
+	 * <p>For consistency, the type of a primitive is specified using its wrapper counterpart,
+	 * i.e. {@code boolean} becomes {@code java.lang.Boolean}. Collections type are harmonized
+	 * to their interface counterpart and defines the actual generic types, i.e.
+	 * {@code java.util.HashMap<java.lang.String,java.lang.Integer>} becomes
+	 * {@code java.util.Map<java.lang.String,java.lang.Integer>}
+	 * <p>Note that this class may be a complex type that gets converted from a String as values
+	 * are bound.
+	 */
+	public String getType() {
+		return this.type;
+	}
+
+	public void setType(String type) {
+		this.type = type;
+	}
+
+	/**
+	 * A short description of the property, if any.
+	 */
+	public String getDescription() {
+		return this.description;
+	}
+
+	public void setDescription(String description) {
+		this.description = description;
+	}
+
+	/**
+	 * The default value, if any.
+	 */
+	public Object getDefaultValue() {
+		return this.defaultValue;
+	}
+
+	public void setDefaultValue(Object defaultValue) {
+		this.defaultValue = defaultValue;
+	}
+
+	/**
+	 * Specify if the property is deprecated
+	 */
+	public boolean isDeprecated() {
+		return this.deprecated;
+	}
+
+	public void setDeprecated(boolean deprecated) {
+		this.deprecated = deprecated;
+	}
+
+}

spring-boot-tools/spring-boot-configuration-metadata/src/main/java/org/springframework/configurationmetadata/ConfigurationMetadataRepository.java

@@ -0,0 +1,46 @@
+/*
+ * 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.configurationmetadata;
+
+import java.util.Map;
+
+/**
+ * A repository of configuration metadata.
+ *
+ * @author Stephane Nicoll
+ * @since 1.2.0
+ */
+public interface ConfigurationMetadataRepository {
+
+	/**
+	 * Defines the name of the "root" group, that is the group that
+	 * gathers all the properties that aren't attached to a specific
+	 * group.
+	 */
+	static final String ROOT_GROUP = "_ROOT_GROUP_";
+
+	/**
+	 * Return the groups, indexed by id.
+	 */
+	Map<String, ConfigurationMetadataGroup> getAllGroups();
+
+	/**
+	 * Return the properties, indexed by id.
+	 */
+	Map<String, ConfigurationMetadataProperty> getAllProperties();
+
+}

spring-boot-tools/spring-boot-configuration-metadata/src/main/java/org/springframework/configurationmetadata/ConfigurationMetadataRepositoryJsonLoader.java

@@ -0,0 +1,98 @@
+/*
+ * 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.configurationmetadata;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.Charset;
+import java.util.Collection;
+
+import org.json.JSONException;
+
+/**
+ * Load a {@link ConfigurationMetadataRepository} from the content of arbitrary resource(s).
+ *
+ * @author Stephane Nicoll
+ * @since 1.2.0
+ */
+public class ConfigurationMetadataRepositoryJsonLoader {
+
+	public static final Charset UTF_8 = Charset.forName("UTF-8");
+
+	private JsonReader reader = new JsonReader();
+
+
+	/**
+	 * Create a {@link ConfigurationMetadataRepository} with the metadata defined by
+	 * the specified {@code resources} using {@link #UTF_8}. If the same config
+	 * metadata items is held within different resources, the first that is loaded is kept.
+	 */
+	public ConfigurationMetadataRepository loadAll(Collection<InputStream> resources) throws IOException {
+		return loadAll(resources, UTF_8);
+	}
+
+	/**
+	 * Create a {@link ConfigurationMetadataRepository} with the metadata defined by
+	 * the specified {@code resources} using the specified {@link Charset}. If the
+	 * same config metadata items is held within different resources, the first that
+	 * is loaded is kept.
+	 */
+	public ConfigurationMetadataRepository loadAll(Collection<InputStream> resources, Charset charset) throws IOException {
+		if (resources == null) {
+			throw new IllegalArgumentException("Resources must not be null.");
+		}
+		if (resources.size() == 1) {
+			return load(resources.iterator().next(), charset);
+		}
+
+		SimpleConfigurationMetadataRepository repository = new SimpleConfigurationMetadataRepository();
+		for (InputStream resource : resources) {
+			SimpleConfigurationMetadataRepository repo = load(resource, charset);
+			repository.include(repo);
+		}
+		return repository;
+	}
+
+	private SimpleConfigurationMetadataRepository load(InputStream stream, Charset charset) throws IOException {
+		try {
+			RawConfigurationMetadata metadata = this.reader.read(stream, charset);
+			return create(metadata);
+		}
+		catch (IOException e) {
+			throw new IllegalArgumentException("Failed to read configuration metadata", e);
+		}
+		catch (JSONException e) {
+			throw new IllegalArgumentException("Invalid configuration metadata document", e);
+		}
+	}
+
+	private SimpleConfigurationMetadataRepository create(RawConfigurationMetadata metadata) {
+		SimpleConfigurationMetadataRepository repository = new SimpleConfigurationMetadataRepository();
+		repository.add(metadata.getSources());
+		for (ConfigurationMetadataItem item : metadata.getItems()) {
+			ConfigurationMetadataSource source = null;
+			String sourceType = item.getSourceType();
+			if (sourceType != null) {
+				source = metadata.getSource(sourceType);
+			}
+			repository.add(item, source);
+		}
+		return repository;
+	}
+
+}
+

spring-boot-tools/spring-boot-configuration-metadata/src/main/java/org/springframework/configurationmetadata/ConfigurationMetadataSource.java

@@ -0,0 +1,110 @@
+/*
+ * 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.configurationmetadata;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * A source of configuration metadata. Also defines where
+ * the source is declared, for instance if it is defined
+ * as a {@code @Bean}.
+ *
+ * @author Stephane Nicoll
+ * @since 1.2.0
+ */
+public class ConfigurationMetadataSource {
+
+	private String groupId;
+
+	private String type;
+
+	private String description;
+
+	private String sourceType;
+
+	private String sourceMethod;
+
+	private final Map<String, ConfigurationMetadataProperty> properties
+			= new HashMap<String, ConfigurationMetadataProperty>();
+
+	/**
+	 * The identifier of the group to which this source is associated
+	 */
+	public String getGroupId() {
+		return this.groupId;
+	}
+
+	void setGroupId(String groupId) {
+		this.groupId = groupId;
+	}
+
+	/**
+	 * The type of the source. Usually this is the fully qualified name
+	 * of a class that defines one more configuration item. This class may or
+	 * may not be available at runtime.
+	 */
+	public String getType() {
+		return this.type;
+	}
+
+	void setType(String type) {
+		this.type = type;
+	}
+
+	/**
+	 * The description of this source, if any.
+	 */
+	public String getDescription() {
+		return this.description;
+	}
+
+	void setDescription(String description) {
+		this.description = description;
+	}
+
+	/**
+	 * The type where this source is defined. This can be identical
+	 * to the {@linkplain #getType() type} if the source is self-defined.
+	 */
+	public String getSourceType() {
+		return this.sourceType;
+	}
+
+	void setSourceType(String sourceType) {
+		this.sourceType = sourceType;
+	}
+
+	/**
+	 * The method name that defines this source, if any.
+	 */
+	public String getSourceMethod() {
+		return this.sourceMethod;
+	}
+
+	void setSourceMethod(String sourceMethod) {
+		this.sourceMethod = sourceMethod;
+	}
+
+	/**
+	 * Return the properties defined by this source.
+	 */
+	public Map<String, ConfigurationMetadataProperty> getProperties() {
+		return this.properties;
+	}
+
+}

spring-boot-tools/spring-boot-configuration-metadata/src/main/java/org/springframework/configurationmetadata/JsonReader.java

@@ -0,0 +1,116 @@
+/*
+ * 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.configurationmetadata;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.nio.charset.Charset;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.json.JSONArray;
+import org.json.JSONObject;
+
+/**
+ * Read standard json metadata format as {@link ConfigurationMetadataRepository}
+ *
+ * @author Stephane Nicoll
+ * @since 1.2.0
+ */
+class JsonReader {
+
+	public static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");
+
+	private static final int BUFFER_SIZE = 4096;
+
+	public RawConfigurationMetadata read(InputStream in) throws IOException {
+		return read(in, DEFAULT_CHARSET);
+	}
+
+	public RawConfigurationMetadata read(InputStream in, Charset charset) throws IOException {
+		JSONObject json = readJson(in, charset);
+		List<ConfigurationMetadataSource> groups = parseAllSources(json);
+		List<ConfigurationMetadataItem> items = parseAllItems(json);
+		return new RawConfigurationMetadata(groups, items);
+	}
+
+	private List<ConfigurationMetadataSource> parseAllSources(JSONObject root) {
+		List<ConfigurationMetadataSource> result = new ArrayList<ConfigurationMetadataSource>();
+		if (!root.has("groups")) {
+			return result;
+		}
+		JSONArray sources = root.getJSONArray("groups");
+		for (int i = 0; i < sources.length(); i++) {
+			JSONObject source = sources.getJSONObject(i);
+			result.add(parseSource(source));
+		}
+		return result;
+	}
+
+	private List<ConfigurationMetadataItem> parseAllItems(JSONObject root) {
+		List<ConfigurationMetadataItem> result = new ArrayList<ConfigurationMetadataItem>();
+		if (!root.has("properties")) {
+			return result;
+		}
+		JSONArray items = root.getJSONArray("properties");
+		for (int i = 0; i < items.length(); i++) {
+			JSONObject item = items.getJSONObject(i);
+			result.add(parseItem(item));
+		}
+		return result;
+	}
+
+	private ConfigurationMetadataSource parseSource(JSONObject json) {
+		ConfigurationMetadataSource source = new ConfigurationMetadataSource();
+		source.setGroupId(json.getString("name"));
+		source.setType(json.optString("type", null));
+		source.setDescription(json.optString("description", null));
+		source.setSourceType(json.optString("sourceType", null));
+		source.setSourceMethod(json.optString("sourceMethod", null));
+		return source;
+	}
+
+	private ConfigurationMetadataItem parseItem(JSONObject json) {
+		ConfigurationMetadataItem item = new ConfigurationMetadataItem();
+		item.setId(json.getString("name"));
+		item.setType(json.optString("type", null));
+		item.setDescription(json.optString("description", null));
+		item.setDefaultValue(json.opt("defaultValue"));
+		item.setDeprecated(json.optBoolean("deprecated", false));
+		item.setSourceType(json.optString("sourceType", null));
+		item.setSourceMethod(json.optString("sourceMethod", null));
+		return item;
+	}
+
+	private JSONObject readJson(InputStream in, Charset charset) throws IOException {
+		try {
+			StringBuilder out = new StringBuilder();
+			InputStreamReader reader = new InputStreamReader(in, charset);
+			char[] buffer = new char[BUFFER_SIZE];
+			int bytesRead = -1;
+			while ((bytesRead = reader.read(buffer)) != -1) {
+				out.append(buffer, 0, bytesRead);
+			}
+			return new JSONObject(out.toString());
+		}
+		finally {
+			in.close();
+		}
+	}
+
+}

spring-boot-tools/spring-boot-configuration-metadata/src/main/java/org/springframework/configurationmetadata/RawConfigurationMetadata.java

@@ -0,0 +1,78 @@
+/*
+ * 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.configurationmetadata;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A raw metadata structure. Used to initialize a {@link ConfigurationMetadataRepository}.
+ *
+ * @author Stephane Nicoll
+ * @since 1.2.0
+ */
+class RawConfigurationMetadata {
+
+	private final List<ConfigurationMetadataSource> sources;
+
+	private final List<ConfigurationMetadataItem> items;
+
+	RawConfigurationMetadata(List<ConfigurationMetadataSource> sources, List<ConfigurationMetadataItem> items) {
+		this.sources = new ArrayList<ConfigurationMetadataSource>(sources);
+		this.items = new ArrayList<ConfigurationMetadataItem>(items);
+		for (ConfigurationMetadataItem item : this.items) {
+			resolveName(item);
+		}
+	}
+
+	public List<ConfigurationMetadataSource> getSources() {
+		return this.sources;
+	}
+
+	public ConfigurationMetadataSource getSource(String type) {
+		for (ConfigurationMetadataSource source : this.sources) {
+			if (type.equals(source.getType())) {
+				return source;
+			}
+		}
+		return null;
+	}
+
+	public List<ConfigurationMetadataItem> getItems() {
+		return this.items;
+	}
+
+	/**
+	 * Resolve the name of an item against this instance.
+	 * @see ConfigurationMetadataProperty#setName(String)
+	 */
+	private void resolveName(ConfigurationMetadataItem item) {
+		item.setName(item.getId()); // fallback
+		if (item.getSourceType() == null) {
+			return;
+		}
+		ConfigurationMetadataSource source = getSource(item.getSourceType());
+		if (source != null) {
+			String groupId = source.getGroupId();
+			String id = item.getId();
+			if (id.startsWith(groupId)) { // match
+				String name = id.substring(groupId.length() + 1, id.length()); // "."
+				item.setName(name);
+			}
+		}
+	}
+}

spring-boot-tools/spring-boot-configuration-metadata/src/main/java/org/springframework/configurationmetadata/SimpleConfigurationMetadataRepository.java

@@ -0,0 +1,115 @@
+/*
+ * 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.configurationmetadata;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * The default {@link ConfigurationMetadataRepository} implementation.
+ *
+ * @author Stephane Nicoll
+ * @since 1.2.0
+ */
+public class SimpleConfigurationMetadataRepository implements ConfigurationMetadataRepository {
+
+	private final Map<String, ConfigurationMetadataGroup> allGroups = new HashMap<String, ConfigurationMetadataGroup>();
+
+	@Override
+	public Map<String, ConfigurationMetadataGroup> getAllGroups() {
+		return Collections.unmodifiableMap(this.allGroups);
+	}
+
+	@Override
+	public Map<String, ConfigurationMetadataProperty> getAllProperties() {
+		Map<String,ConfigurationMetadataProperty> properties = new HashMap<String, ConfigurationMetadataProperty>();
+		for (ConfigurationMetadataGroup group : this.allGroups.values()) {
+			properties.putAll(group.getProperties());
+		}
+		return properties;
+	}
+
+	/**
+	 * Register the specified {@link ConfigurationMetadataSource sources}.
+	 */
+	public void add(Collection<ConfigurationMetadataSource> sources) {
+		for (ConfigurationMetadataSource source : sources) {
+			String groupId = source.getGroupId();
+			ConfigurationMetadataGroup group = this.allGroups.get(groupId);
+			if (group == null) {
+				group = new ConfigurationMetadataGroup(groupId);
+				this.allGroups.put(groupId, group);
+			}
+			String sourceType = source.getType();
+			if (sourceType != null) {
+				group.getSources().putIfAbsent(sourceType, source);
+			}
+		}
+	}
+
+	/**
+	 * Add a {@link ConfigurationMetadataProperty} with the {@link ConfigurationMetadataSource source}
+	 * that defines it, if any.
+	 */
+	public void add(ConfigurationMetadataProperty property, ConfigurationMetadataSource source) {
+		if (source != null) {
+			source.getProperties().putIfAbsent(property.getId(), property);
+		}
+		getGroup(source).getProperties().putIfAbsent(property.getId(), property);
+	}
+
+
+	/**
+	 * Merge the content of the specified repository to this repository.
+	 */
+	public void include(ConfigurationMetadataRepository repository) {
+		for (ConfigurationMetadataGroup group : repository.getAllGroups().values()) {
+			ConfigurationMetadataGroup existingGroup = this.allGroups.get(group.getId());
+			if (existingGroup == null)  {
+				this.allGroups.put(group.getId(), group);
+			}
+			else {
+				// Merge properties
+				for (Map.Entry<String, ConfigurationMetadataProperty> entry : group.getProperties().entrySet()) {
+					existingGroup.getProperties().putIfAbsent(entry.getKey(), entry.getValue());
+				}
+				// Merge sources
+				for (Map.Entry<String, ConfigurationMetadataSource> entry : group.getSources().entrySet()) {
+					existingGroup.getSources().putIfAbsent(entry.getKey(), entry.getValue());
+				}
+			}
+		}
+
+	}
+
+	private ConfigurationMetadataGroup getGroup(ConfigurationMetadataSource source) {
+		if (source == null) {
+			ConfigurationMetadataGroup rootGroup = this.allGroups.get(ROOT_GROUP);
+			if (rootGroup == null) {
+				rootGroup = new ConfigurationMetadataGroup(ROOT_GROUP);
+				this.allGroups.put(ROOT_GROUP, rootGroup);
+			}
+			return rootGroup;
+		}
+		else {
+			return this.allGroups.get(source.getGroupId());
+		}
+	}
+
+}

spring-boot-tools/spring-boot-configuration-metadata/src/test/java/org/springframework/configurationmetadata/AbstractConfigurationMetadataTests.java

@@ -0,0 +1,66 @@
+/*
+ * 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.configurationmetadata;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import org.junit.Rule;
+import org.junit.rules.ExpectedException;
+
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+/**
+ *
+ * @author Stephane Nicoll
+ */
+public abstract class AbstractConfigurationMetadataTests {
+
+	@Rule
+	public final ExpectedException thrown = ExpectedException.none();
+
+	protected void assertSource(ConfigurationMetadataSource actual, String groupId, String type, String sourceType) {
+		assertNotNull(actual);
+		assertEquals(groupId, actual.getGroupId());
+		assertEquals(type, actual.getType());
+		assertEquals(sourceType, actual.getSourceType());
+	}
+
+	protected void assertProperty(ConfigurationMetadataProperty actual, String id, String name,
+			Class<?> type, Object defaultValue) {
+		assertNotNull(actual);
+		assertEquals(id, actual.getId());
+		assertEquals(name, actual.getName());
+		String typeName = type != null ? type.getName() : null;
+		assertEquals(typeName, actual.getType());
+		assertEquals(defaultValue, actual.getDefaultValue());
+	}
+
+	protected void assertItem(ConfigurationMetadataItem actual, String sourceType) {
+		assertNotNull(actual);
+		assertEquals(sourceType, actual.getSourceType());
+	}
+
+	protected InputStream getInputStreamFor(String name) throws IOException {
+		Resource r = new ClassPathResource("metadata/configuration-metadata-" + name + ".json");
+		return r.getInputStream();
+	}
+}

spring-boot-tools/spring-boot-configuration-metadata/src/test/java/org/springframework/configurationmetadata/ConfigurationMetadataRepositoryJsonLoaderTests.java

@@ -0,0 +1,122 @@
+/*
+ * 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.configurationmetadata;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Map;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Tests for {@link ConfigurationMetadataRepository}.
+ *
+ * @author Stephane Nicoll
+ */
+public class ConfigurationMetadataRepositoryJsonLoaderTests extends AbstractConfigurationMetadataTests {
+
+	private final ConfigurationMetadataRepositoryJsonLoader loader = new ConfigurationMetadataRepositoryJsonLoader();
+
+	@Test
+	public void nullResource() throws IOException {
+		thrown.expect(IllegalArgumentException.class);
+		loader.loadAll(null);
+	}
+
+	@Test
+	public void simpleRepository() throws IOException {
+		ConfigurationMetadataRepository repo = loader.loadAll(Collections.singleton(getInputStreamFor("foo")));
+		validateFoo(repo);
+		assertEquals(1, repo.getAllGroups().size());
+
+		contains(repo.getAllProperties(), "spring.foo.name", "spring.foo.description", "spring.foo.counter");
+		assertEquals(3, repo.getAllProperties().size());
+	}
+
+	@Test
+	public void severalRepositoriesNoConflict() throws IOException {
+		ConfigurationMetadataRepository repo = loader.loadAll(
+				Arrays.asList(getInputStreamFor("foo"), getInputStreamFor("bar")));
+		validateFoo(repo);
+		validateBar(repo);
+		assertEquals(2, repo.getAllGroups().size());
+
+		contains(repo.getAllProperties(), "spring.foo.name", "spring.foo.description", "spring.foo.counter",
+				"spring.bar.name", "spring.bar.description", "spring.bar.counter");
+		assertEquals(6, repo.getAllProperties().size());
+	}
+
+	@Test
+	public void repositoryWithRoot() throws IOException {
+		ConfigurationMetadataRepository repo = loader.loadAll(
+				Arrays.asList(getInputStreamFor("foo"), getInputStreamFor("root")));
+		validateFoo(repo);
+		assertEquals(2, repo.getAllGroups().size());
+
+		contains(repo.getAllProperties(), "spring.foo.name", "spring.foo.description", "spring.foo.counter",
+				"spring.root.name", "spring.root2.name");
+		assertEquals(5, repo.getAllProperties().size());
+	}
+
+	@Test
+	public void severalRepositoriesIdenticalGroups() throws IOException {
+		ConfigurationMetadataRepository repo = loader.loadAll(
+				Arrays.asList(getInputStreamFor("foo"), getInputStreamFor("foo2")));
+		assertEquals(1, repo.getAllGroups().size());
+		ConfigurationMetadataGroup group = repo.getAllGroups().get("spring.foo");
+		contains(group.getSources(), "org.acme.Foo", "org.acme.Foo2", "org.springframework.boot.FooProperties");
+		assertEquals(3, group.getSources().size());
+		contains(group.getProperties(), "spring.foo.name", "spring.foo.description", "spring.foo.counter",
+				"spring.foo.enabled", "spring.foo.type");
+		assertEquals(5, group.getProperties().size());
+		contains(repo.getAllProperties(), "spring.foo.name", "spring.foo.description", "spring.foo.counter",
+				"spring.foo.enabled", "spring.foo.type");
+		assertEquals(5, repo.getAllProperties().size());
+	}
+
+	private void validateFoo(ConfigurationMetadataRepository repo) {
+		ConfigurationMetadataGroup group = repo.getAllGroups().get("spring.foo");
+		contains(group.getSources(), "org.acme.Foo", "org.springframework.boot.FooProperties");
+		ConfigurationMetadataSource source = group.getSources().get("org.acme.Foo");
+		contains(source.getProperties(), "spring.foo.name", "spring.foo.description");
+		assertEquals(2, source.getProperties().size());
+		ConfigurationMetadataSource source2 = group.getSources().get("org.springframework.boot.FooProperties");
+		contains(source2.getProperties(), "spring.foo.name", "spring.foo.counter");
+		assertEquals(2, source2.getProperties().size());
+	}
+
+	private void validateBar(ConfigurationMetadataRepository repo) {
+		ConfigurationMetadataGroup group = repo.getAllGroups().get("spring.bar");
+		contains(group.getSources(), "org.acme.Bar", "org.springframework.boot.BarProperties");
+		ConfigurationMetadataSource source = group.getSources().get("org.acme.Bar");
+		contains(source.getProperties(), "spring.bar.name", "spring.bar.description");
+		assertEquals(2, source.getProperties().size());
+		ConfigurationMetadataSource source2 = group.getSources().get("org.springframework.boot.BarProperties");
+		contains(source2.getProperties(), "spring.bar.name", "spring.bar.counter");
+		assertEquals(2, source2.getProperties().size());
+	}
+
+	private void contains(Map<String, ?> source, String... keys) {
+		for (String key : keys) {
+			assertTrue("Item '" + key + "' not found. Got " + source.keySet(), source.containsKey(key));
+		}
+	}
+}

spring-boot-tools/spring-boot-configuration-metadata/src/test/java/org/springframework/configurationmetadata/JsonReaderTests.java

@@ -0,0 +1,86 @@
+/*
+ * 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.configurationmetadata;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.json.JSONException;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+/**
+ * Tests for {@link JsonReader}
+ *
+ * @author Stephane Nicoll
+ */
+public class JsonReaderTests extends AbstractConfigurationMetadataTests {
+
+	private final JsonReader reader = new JsonReader();
+
+	@Test
+	public void emptyMetadata() throws IOException {
+		RawConfigurationMetadata rawMetadata = reader.read(getInputStreamFor("empty"));
+		assertEquals(0, rawMetadata.getSources().size());
+		assertEquals(0, rawMetadata.getItems().size());
+	}
+
+	@Test
+	public void invalidMetadata() throws IOException {
+		thrown.expect(JSONException.class);
+		reader.read(getInputStreamFor("invalid"));
+	}
+
+	@Test
+	public void simpleMetadata() throws IOException {
+		RawConfigurationMetadata rawMetadata = reader.read(getInputStreamFor("foo"));
+		List<ConfigurationMetadataSource> sources = rawMetadata.getSources();
+		assertEquals(2, sources.size());
+		List<ConfigurationMetadataItem> items = rawMetadata.getItems();
+		assertEquals(4, items.size());
+
+
+		ConfigurationMetadataSource source = sources.get(0);
+		assertSource(source, "spring.foo", "org.acme.Foo", "org.acme.config.FooApp");
+		assertEquals("foo()", source.getSourceMethod());
+		assertEquals("This is Foo.", source.getDescription());
+		ConfigurationMetadataItem item = items.get(0);
+		assertProperty(item, "spring.foo.name", "name", String.class, null);
+		assertItem(item, "org.acme.Foo");
+		ConfigurationMetadataItem item2 = items.get(1);
+		assertProperty(item2, "spring.foo.description", "description", String.class, "FooBar");
+		assertEquals("Foo description.", item2.getDescription());
+		assertNull(item2.getSourceMethod());
+		assertItem(item2, "org.acme.Foo");
+	}
+
+	@Test
+	public void rootMetadata() throws IOException {
+		RawConfigurationMetadata rawMetadata = reader.read(getInputStreamFor("root"));
+		List<ConfigurationMetadataSource> sources = rawMetadata.getSources();
+		assertEquals(0, sources.size());
+		List<ConfigurationMetadataItem> items = rawMetadata.getItems();
+		assertEquals(2, items.size());
+
+		ConfigurationMetadataItem item = items.get(0);
+		assertProperty(item, "spring.root.name", "spring.root.name", String.class, null);
+
+	}
+
+}

spring-boot-tools/spring-boot-configuration-metadata/src/test/resources/metadata/configuration-metadata-bar.json

@@ -0,0 +1,40 @@
+{
+  "groups": [
+    {
+      "name": "spring.bar",
+      "type": "org.acme.Bar",
+      "sourceType": "org.acme.config.BarApp",
+      "sourceMethod": "bar()",
+      "description": "This is Bar."
+    },
+    {
+      "name": "spring.bar",
+      "type": "org.springframework.boot.BarProperties"
+    }
+  ],
+  "properties": [
+    {
+      "name": "spring.bar.name",
+      "type": "java.lang.String",
+      "sourceType": "org.acme.Bar"
+    },
+    {
+      "name": "spring.bar.description",
+      "type": "java.lang.String",
+      "sourceType": "org.acme.Bar",
+      "description": "Bar description.",
+      "defaultValue": "BarFoo"
+    },
+    {
+      "name": "spring.bar.name",
+      "type": "java.lang.String",
+      "sourceType": "org.springframework.boot.BarProperties"
+    },
+    {
+      "name": "spring.bar.counter",
+      "type": "java.lang.Integer",
+      "sourceType": "org.springframework.boot.BarProperties",
+      "defaultValue": 0
+    }
+  ]
+}

spring-boot-tools/spring-boot-configuration-metadata/src/test/resources/metadata/configuration-metadata-empty.json

@@ -0,0 +1,3 @@
+{
+  "foo": "bar"
+}

spring-boot-tools/spring-boot-configuration-metadata/src/test/resources/metadata/configuration-metadata-foo.json

@@ -0,0 +1,40 @@
+{
+  "groups": [
+    {
+      "name": "spring.foo",
+      "type": "org.acme.Foo",
+      "sourceType": "org.acme.config.FooApp",
+      "sourceMethod": "foo()",
+      "description": "This is Foo."
+    },
+    {
+      "name": "spring.foo",
+      "type": "org.springframework.boot.FooProperties"
+    }
+  ],
+  "properties": [
+    {
+      "name": "spring.foo.name",
+      "type": "java.lang.String",
+      "sourceType": "org.acme.Foo"
+    },
+    {
+      "name": "spring.foo.description",
+      "type": "java.lang.String",
+      "sourceType": "org.acme.Foo",
+      "description": "Foo description.",
+      "defaultValue": "FooBar"
+    },
+    {
+      "name": "spring.foo.name",
+      "type": "java.lang.String",
+      "sourceType": "org.springframework.boot.FooProperties"
+    },
+    {
+      "name": "spring.foo.counter",
+      "type": "java.lang.Integer",
+      "sourceType": "org.springframework.boot.FooProperties",
+      "defaultValue": 0
+    }
+  ]
+}

spring-boot-tools/spring-boot-configuration-metadata/src/test/resources/metadata/configuration-metadata-foo2.json

@@ -0,0 +1,23 @@
+{
+  "groups": [
+    {
+      "name": "spring.foo",
+      "type": "org.acme.Foo2",
+      "sourceType": "org.acme.config.FooApp",
+      "sourceMethod": "foo2()",
+      "description": "This is Foo2."
+    }
+  ],
+  "properties": [
+    {
+      "name": "spring.foo.enabled",
+      "type": "java.lang.Boolean",
+      "sourceType": "org.acme.Foo2"
+    },
+    {
+      "name": "spring.foo.type",
+      "type": "java.lang.String",
+      "sourceType": "org.acme.Foo2"
+    }
+  ]
+}

spring-boot-tools/spring-boot-configuration-metadata/src/test/resources/metadata/configuration-metadata-invalid.json

@@ -0,0 +1,8 @@
+{
+  "properties": [
+    {
+      "type": "java.lang.String",
+      "sourceType": "org.acme.Invalid"
+    }
+  ]
+}

spring-boot-tools/spring-boot-configuration-metadata/src/test/resources/metadata/configuration-metadata-root.json

@@ -0,0 +1,11 @@
+{
+  "properties": [
+    {
+      "name": "spring.root.name",
+      "type": "java.lang.String"
+    },
+    {
+      "name": "spring.root2.name"
+    }
+  ]
+}