Fix property names with successive capital letters

Previously, if a property name had successive capital letters, the
generated meta-data would clean it in such a way it is defined as a
regular word. For instance a `myFOO` property would be written as
`my-foo` in the meta-data.

It turns out this decision is wrong as the binder has no way to compute
back the name of the property and therefore `my-foo` wouldn't bind to
`setMyFOO` as it should.

This commit updates the meta-data name generation algorithm to properly
identify such cases: `myFOO` now translates to `my-f-o-o`. While the
generated name is a bit ugly, it now provides a consistent binding
experience.

Closes gh-5330

Author: snicoll

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

@@ -1,5 +1,5 @@
 /*
- * 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.
@@ -17,11 +17,10 @@
 package org.springframework.boot.configurationprocessor.metadata;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import java.util.ListIterator;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
 
 import org.springframework.util.CollectionUtils;
 import org.springframework.util.LinkedMultiValueMap;
@@ -38,7 +37,7 @@
  */
 public class ConfigurationMetadata {
 
-	private static final Pattern CAMEL_CASE_PATTERN = Pattern.compile("([^A-Z-])([A-Z])");
+	private static final List<Character> SEPARATORS = Arrays.asList('-', '_');
 
 	private final MultiValueMap<String, ItemMetadata> items;
 
@@ -160,23 +159,23 @@ public static String nestedPrefix(String prefix, String name) {
 	}
 
 	static String toDashedCase(String name) {
-		Matcher matcher = CAMEL_CASE_PATTERN.matcher(name);
-		StringBuffer result = new StringBuffer();
-		while (matcher.find()) {
-			matcher.appendReplacement(result, getDashed(matcher));
-		}
-		matcher.appendTail(result);
-		return result.toString().toLowerCase();
-	}
+		StringBuilder sb = new StringBuilder();
+		Character previous = null;
+		for (char current : name.toCharArray()) {
+			if (SEPARATORS.contains(current)) {
+				sb.append("-");
+			}
+			else if (Character.isUpperCase(current) && previous != null
+					&& !SEPARATORS.contains(previous)) {
+				sb.append("-").append(current);
+			}
+			else {
+				sb.append(current);
+			}
+			previous = current;
 
-	private static String getDashed(Matcher matcher) {
-		String first = matcher.group(1);
-		String second = matcher.group(2);
-		if (first.equals("_")) {
-			// not a word for the binder
-			return first + second;
 		}
-		return first + "-" + second;
+		return sb.toString().toLowerCase();
 	}
 
 	private static <T extends Comparable<T>> List<T> flattenValues(

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2014 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.
@@ -33,35 +33,45 @@ public void toDashedCaseCamelCase() {
 		assertThat(toDashedCase("simpleCamelCase"), is("simple-camel-case"));
 	}
 
+	@Test
+	public void toDashedCaseUpperCamelCaseSuffix() {
+		assertThat(toDashedCase("myDLQ"), is("my-d-l-q"));
+	}
+
+	@Test
+	public void toDashedCaseUpperCamelCaseMiddle() {
+		assertThat(toDashedCase("someDLQKey"), is("some-d-l-q-key"));
+	}
+
 	@Test
 	public void toDashedCaseWordsUnderscore() {
-		assertThat(toDashedCase("Word_With_underscore"), is("word_with_underscore"));
+		assertThat(toDashedCase("Word_With_underscore"), is("word-with-underscore"));
 	}
 
 	@Test
 	public void toDashedCaseWordsSeveralUnderscores() {
 		assertThat(toDashedCase("Word___With__underscore"),
-				is("word___with__underscore"));
+				is("word---with--underscore"));
 	}
 
 	@Test
 	public void toDashedCaseLowerCaseUnderscore() {
-		assertThat(toDashedCase("lower_underscore"), is("lower_underscore"));
+		assertThat(toDashedCase("lower_underscore"), is("lower-underscore"));
 	}
 
 	@Test
-	public void toDashedCaseUpperUnderscore() {
-		assertThat(toDashedCase("UPPER_UNDERSCORE"), is("upper_underscore"));
+	public void toDashedCaseUpperUnderscoreSuffix() {
+		assertThat(toDashedCase("my_DLQ"), is("my-d-l-q"));
 	}
 
 	@Test
-	public void toDashedCaseMultipleUnderscores() {
-		assertThat(toDashedCase("super___crazy"), is("super___crazy"));
+	public void toDashedCaseUpperUnderscoreMiddle() {
+		assertThat(toDashedCase("some_DLQ_key"), is("some-d-l-q-key"));
 	}
 
 	@Test
-	public void toDashedCaseUppercase() {
-		assertThat(toDashedCase("UPPERCASE"), is("uppercase"));
+	public void toDashedCaseMultipleUnderscores() {
+		assertThat(toDashedCase("super___crazy"), is("super---crazy"));
 	}
 
 	@Test

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

@@ -1,5 +1,5 @@
 /*
- * 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.
@@ -170,6 +170,12 @@ public void propertyWithAllUpperCaseSuffixCanBeBound() throws Exception {
 		assertEquals("baz", foo.fooBarURI);
 	}
 
+	@Test
+	public void propertyWithAllUpperCaseInTheMiddleCanBeBound() throws Exception {
+		Foo foo = createFoo("foo-d-l-q-bar:baz");
+		assertEquals("baz", foo.fooDLQBar);
+	}
+
 	private Foo createFoo(final String values) throws Exception {
 		setupFactory();
 		return bindFoo(values);
@@ -203,6 +209,8 @@ public static class Foo {
 
 		private String fooBarURI;
 
+		private String fooDLQBar;
+
 		public String getSpringFooBaz() {
 			return this.spring_foo_baz;
 		}
@@ -243,6 +251,13 @@ public void setFooBarURI(String fooBarURI) {
 			this.fooBarURI = fooBarURI;
 		}
 
+		public String getFooDLQBar() {
+			return this.fooDLQBar;
+		}
+
+		public void setFooDLQBar(String fooDLQBar) {
+			this.fooDLQBar = fooDLQBar;
+		}
 	}
 
 }