Support relaxed binding to 'mixedCASE' names

Update relaxed binding so that names of the form `initSQL` can now
be bound against properties of the form `init-s-q-l`.

Fixes gh-6803

spring-boot/src/main/java/org/springframework/boot/bind/RelaxedNames.java

@@ -232,7 +232,13 @@ public final class RelaxedNames implements Iterable<String> {
 	 * @return the relaxed names
 	 */
 	public static RelaxedNames forCamelCase(String name) {
-		return new RelaxedNames(Manipulation.CAMELCASE_TO_HYPHEN.apply(name));
+		StringBuffer result = new StringBuffer();
+		for (char c : name.toCharArray()) {
+			result.append(Character.isUpperCase(c) && result.length() > 0
+					&& result.charAt(result.length() - 1) != '-'
+							? "-" + Character.toLowerCase(c) : c);
+		}
+		return new RelaxedNames(result.toString());
 	}
 
 }

spring-boot/src/test/java/org/springframework/boot/bind/RelaxedDataBinderTests.java

@@ -653,6 +653,17 @@ public class RelaxedDataBinderTests {
 		assertThat(target.getObjects()).containsExactly("teststring");
 	}
 
+	@Test
+	public void testMixedWithUpperCaseWord() throws Exception {
+		// gh-6803
+		VanillaTarget target = new VanillaTarget();
+		RelaxedDataBinder binder = getBinder(target, "test");
+		MutablePropertyValues values = new MutablePropertyValues();
+		values.add("test.mixed-u-p-p-e-r", "foo");
+		binder.bind(values);
+		assertThat(target.getMixedUPPER()).isEqualTo("foo");
+	}
+
 	private void doTestBindCaseInsensitiveEnums(VanillaTarget target) throws Exception {
 		BindingResult result = bind(target, "bingo: THIS");
 		assertThat(result.getErrorCount()).isEqualTo(0);
@@ -1013,6 +1024,8 @@ public class RelaxedDataBinderTests {
 
 		private List<Object> objects;
 
+		private String mixedUPPER;
+
 		public char[] getBar() {
 			return this.bar;
 		}
@@ -1077,6 +1090,14 @@ public class RelaxedDataBinderTests {
 			this.objects = objects;
 		}
 
+		public String getMixedUPPER() {
+			return this.mixedUPPER;
+		}
+
+		public void setMixedUPPER(String mixedUPPER) {
+			this.mixedUPPER = mixedUPPER;
+		}
+
 	}
 
 	enum Bingo {

spring-boot/src/test/java/org/springframework/boot/bind/RelaxedNamesTests.java

@@ -123,4 +123,28 @@ public class RelaxedNamesTests {
 		assertThat(iterator.hasNext()).isFalse();
 	}
 
+	@Test
+	public void forCamelCase() throws Exception {
+		Iterator<String> iterator = RelaxedNames.forCamelCase("camelCase").iterator();
+		assertThat(iterator.next()).isEqualTo("camel-case");
+		assertThat(iterator.next()).isEqualTo("camel_case");
+		assertThat(iterator.next()).isEqualTo("camelCase");
+		assertThat(iterator.next()).isEqualTo("camelcase");
+		assertThat(iterator.next()).isEqualTo("CAMEL-CASE");
+		assertThat(iterator.next()).isEqualTo("CAMEL_CASE");
+		assertThat(iterator.next()).isEqualTo("CAMELCASE");
+	}
+
+	@Test
+	public void forCamelCaseWithCaps() throws Exception {
+		Iterator<String> iterator = RelaxedNames.forCamelCase("camelCASE").iterator();
+		assertThat(iterator.next()).isEqualTo("camel-c-a-s-e");
+		assertThat(iterator.next()).isEqualTo("camel_c_a_s_e");
+		assertThat(iterator.next()).isEqualTo("camelCASE");
+		assertThat(iterator.next()).isEqualTo("camelcase");
+		assertThat(iterator.next()).isEqualTo("CAMEL-C-A-S-E");
+		assertThat(iterator.next()).isEqualTo("CAMEL_C_A_S_E");
+		assertThat(iterator.next()).isEqualTo("CAMELCASE");
+	}
+
 }

spring-boot/src/test/java/org/springframework/boot/context/properties/ConfigurationPropertiesBindingPostProcessorTests.java

@@ -298,12 +298,14 @@ public class ConfigurationPropertiesBindingPostProcessorTests {
 
 	@Test
 	public void relaxedPropertyNamesSame() throws Exception {
-		testRelaxedPropertyNames("test.FOO_BAR=test1", "test.FOO_BAR=test2");
+		testRelaxedPropertyNames("test.FOO_BAR=test1", "test.FOO_BAR=test2",
+				"test.BAR-B-A-Z=testa", "test.BAR-B-A-Z=testb");
 	}
 
 	@Test
 	public void relaxedPropertyNamesMixed() throws Exception {
-		testRelaxedPropertyNames("test.FOO_BAR=test2", "test.foo-bar=test1");
+		testRelaxedPropertyNames("test.FOO_BAR=test2", "test.foo-bar=test1",
+				"test.BAR-B-A-Z=testb", "test.bar_b_a_z=testa");
 	}
 
 	private void testRelaxedPropertyNames(String... environment) {
@@ -312,8 +314,9 @@ public class ConfigurationPropertiesBindingPostProcessorTests {
 				environment);
 		this.context.register(RelaxedPropertyNames.class);
 		this.context.refresh();
-		assertThat(this.context.getBean(RelaxedPropertyNames.class).getFooBar())
-				.isEqualTo("test2");
+		RelaxedPropertyNames bean = this.context.getBean(RelaxedPropertyNames.class);
+		assertThat(bean.getFooBar()).isEqualTo("test2");
+		assertThat(bean.getBarBAZ()).isEqualTo("testb");
 	}
 
 	@Test
@@ -670,6 +673,8 @@ public class ConfigurationPropertiesBindingPostProcessorTests {
 
 		private String fooBar;
 
+		private String barBAZ;
+
 		public String getFooBar() {
 			return this.fooBar;
 		}
@@ -678,6 +683,14 @@ public class ConfigurationPropertiesBindingPostProcessorTests {
 			this.fooBar = fooBar;
 		}
 
+		public String getBarBAZ() {
+			return this.barBAZ;
+		}
+
+		public void setBarBAZ(String barBAZ) {
+			this.barBAZ = barBAZ;
+		}
+
 	}
 
 	@SuppressWarnings("rawtypes")