Polish contribution

Closes gh-5335

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

 /*
- * Copyright 2012-2015 the original author or authors.
+ * 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.
@@ -77,12 +77,18 @@ class RawConfigurationMetadata {
 		}
 		ConfigurationMetadataSource source = getSource(item.getSourceType());
 		if (source != null) {
-			String dottedPrefix = source.getGroupId() + ".";
+			String groupId = source.getGroupId();
+			String dottedPrefix = groupId + ".";
 			String id = item.getId();
-			if (id.startsWith(dottedPrefix)) {
+			if (hasLength(groupId) && id.startsWith(dottedPrefix)) {
 				String name = id.substring(dottedPrefix.length(), id.length());
 				item.setName(name);
 			}
 		}
 	}
+
+	private static boolean hasLength(String s) {
+		return (s != null && s.length() > 0);
+	}
+
 }

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

 /*
- * Copyright 2012-2015 the original author or authors.
+ * 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.
@@ -123,6 +123,22 @@ public class ConfigurationMetadataRepositoryJsonBuilderTests
 		}
 	}
 
+	@Test
+	public void emptyGroups() throws IOException {
+		InputStream in = getInputStreamFor("empty-groups");
+		try {
+			ConfigurationMetadataRepository repo = ConfigurationMetadataRepositoryJsonBuilder
+					.create(in).build();
+			validateEmptyGroup(repo);
+			assertEquals(1, repo.getAllGroups().size());
+			contains(repo.getAllProperties(), "name", "title");
+			assertEquals(2, repo.getAllProperties().size());
+		}
+		finally {
+			in.close();
+		}
+	}
+
 	@Test
 	public void builderInstancesAreIsolated() throws IOException {
 		InputStream foo = getInputStreamFor("foo");
@@ -184,6 +200,20 @@ public class ConfigurationMetadataRepositoryJsonBuilderTests
 		validatePropertyHints(repo.getAllProperties().get("spring.bar.counter"), 0, 0);
 	}
 
+	private void validateEmptyGroup(ConfigurationMetadataRepository repo) {
+		ConfigurationMetadataGroup group = repo.getAllGroups().get("");
+		contains(group.getSources(), "org.acme.Foo", "org.acme.Bar");
+		ConfigurationMetadataSource source = group.getSources().get("org.acme.Foo");
+		contains(source.getProperties(), "name");
+		assertEquals(1, source.getProperties().size());
+		ConfigurationMetadataSource source2 = group.getSources()
+				.get("org.acme.Bar");
+		contains(source2.getProperties(), "title");
+		assertEquals(1, source2.getProperties().size());
+		validatePropertyHints(repo.getAllProperties().get("name"), 0, 0);
+		validatePropertyHints(repo.getAllProperties().get("title"), 0, 0);
+	}
+
 	private void validatePropertyHints(ConfigurationMetadataProperty property,
 			int valueHints, int valueProviders) {
 		assertEquals(valueHints, property.getValueHints().size());

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

@@ -54,13 +54,14 @@ public class JsonReaderTests extends AbstractConfigurationMetadataTests {
 
 	@Test
 	public void emptyGroupName() throws IOException {
-		RawConfigurationMetadata rawMetadata = readFor("emptygroup");
+		RawConfigurationMetadata rawMetadata = readFor("empty-groups");
 		List<ConfigurationMetadataItem> items = rawMetadata.getItems();
-		assertEquals(1, items.size());
-
-		ConfigurationMetadataItem item = items.get(0);
-		assertProperty(item, "name", "name", String.class, null);
+		assertEquals(2, items.size());
 
+		ConfigurationMetadataItem name = items.get(0);
+		assertProperty(name, "name", "name", String.class, null);
+		ConfigurationMetadataItem dotTitle = items.get(1);
+		assertProperty(dotTitle, "title", "title", String.class, null);
 	}
 
 	@Test

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

@@ -6,6 +6,13 @@
       "sourceType": "org.acme.config.FooApp",
       "sourceMethod": "foo()",
       "description": "This is Foo."
+    },
+    {
+      "name": "",
+      "type": "org.acme.Bar",
+      "sourceType": "org.acme.config.FooApp",
+      "sourceMethod": "bar()",
+      "description": "This is Bar."
     }
   ],
   "properties": [
@@ -13,6 +20,11 @@
       "name": "name",
       "type": "java.lang.String",
       "sourceType": "org.acme.Foo"
+    },
+    {
+      "name": "title",
+      "type": "java.lang.String",
+      "sourceType": "org.acme.Bar"
     }
   ]
 }