Add more smarts to properties binding

* Underscores are allowed as nested property field separators
* System and env vars are only considered for binding if they
look like they apply to a given bean when ignoreUnknownFields
is false

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

@@ -16,8 +16,11 @@
 
 package org.springframework.boot.bind;
 
+import java.beans.PropertyDescriptor;
+import java.util.HashSet;
 import java.util.Locale;
 import java.util.Properties;
+import java.util.Set;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -240,9 +243,23 @@ public class PropertiesConfigurationFactory<T> implements FactoryBean<T>,
 		dataBinder.setIgnoreUnknownFields(this.ignoreUnknownFields);
 		customizeBinder(dataBinder);
 
+		Set<String> names = new HashSet<String>();
+		if (this.target != null) {
+			PropertyDescriptor[] descriptors = BeanUtils
+					.getPropertyDescriptors(this.target.getClass());
+			for (PropertyDescriptor descriptor : descriptors) {
+				String name = descriptor.getName();
+				if (!name.equals("class")) {
+					names.add(name);
+					names.add(name + ".*");
+					names.add(name + "_*");
+				}
+			}
+		}
+
 		PropertyValues propertyValues = (this.properties != null ? new MutablePropertyValues(
-				this.properties)
+				this.properties) : new PropertySourcesPropertyValues(
-				: new PropertySourcesPropertyValues(this.propertySources));
+				this.propertySources, names));
 		dataBinder.bind(propertyValues);
 
 		if (this.validator != null) {

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

@@ -29,6 +29,7 @@ import org.springframework.core.env.PropertySource;
 import org.springframework.core.env.PropertySources;
 import org.springframework.core.env.PropertySourcesPropertyResolver;
 import org.springframework.core.env.StandardEnvironment;
+import org.springframework.util.PatternMatchUtils;
 import org.springframework.validation.DataBinder;
 
 /**
@@ -44,23 +45,40 @@ public class PropertySourcesPropertyValues implements PropertyValues {
 
 	private PropertySources propertySources;
 
+	private Collection<String> NON_ENUMERABLES = Arrays.asList(
+			StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME,
+			StandardEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME);;
+
 	/**
 	 * Create a new PropertyValues from the given PropertySources
 	 * @param propertySources a PropertySources instance
 	 */
 	public PropertySourcesPropertyValues(PropertySources propertySources) {
+		this(propertySources, null);
+	}
+
+	/**
+	 * Create a new PropertyValues from the given PropertySources
+	 * @param propertySources a PropertySources instance
+	 * @param systemPropertyNames property names to include from system properties and
+	 * environment variables
+	 */
+	public PropertySourcesPropertyValues(PropertySources propertySources,
+			Collection<String> systemPropertyNames) {
 		this.propertySources = propertySources;
-		Collection<String> nonEnumerables = Arrays.asList(
-				StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME,
-				StandardEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME);
 		PropertySourcesPropertyResolver resolver = new PropertySourcesPropertyResolver(
 				propertySources);
+		String[] includes = systemPropertyNames == null ? new String[0]
+				: systemPropertyNames.toArray(new String[0]);
 		for (PropertySource<?> source : propertySources) {
-			if (source instanceof EnumerablePropertySource
+			if (source instanceof EnumerablePropertySource) {
-					&& !nonEnumerables.contains(source.getName())) {
 				EnumerablePropertySource<?> enumerable = (EnumerablePropertySource<?>) source;
 				if (enumerable.getPropertyNames().length > 0) {
 					for (String propertyName : enumerable.getPropertyNames()) {
+						if (this.NON_ENUMERABLES.contains(source.getName())
+								&& !PatternMatchUtils.simpleMatch(includes, propertyName)) {
+							continue;
+						}
 						Object value = source.getProperty(propertyName);
 						try {
 							value = resolver.getProperty(propertyName);

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

@@ -102,7 +102,7 @@ public class RelaxedDataBinder extends DataBinder {
 	private MutablePropertyValues modifyProperties(MutablePropertyValues propertyValues,
 			Object target) {
 
-		propertyValues = getProperyValuesForNamePrefix(propertyValues);
+		propertyValues = getPropertyValuesForNamePrefix(propertyValues);
 
 		if (target instanceof MapHolder) {
 			propertyValues = addMapPrefix(propertyValues);
@@ -126,26 +126,18 @@ public class RelaxedDataBinder extends DataBinder {
 		return rtn;
 	}
 
-	private MutablePropertyValues getProperyValuesForNamePrefix(
+	private MutablePropertyValues getPropertyValuesForNamePrefix(
 			MutablePropertyValues propertyValues) {
 		if (!StringUtils.hasText(this.namePrefix) && !this.ignoreNestedProperties) {
 			return propertyValues;
 		}
-		int prefixLength = StringUtils.hasText(this.namePrefix) ? this.namePrefix
-				.length() : 0;
 		MutablePropertyValues rtn = new MutablePropertyValues();
 		for (PropertyValue pv : propertyValues.getPropertyValues()) {
 			String name = pv.getName();
-			if (this.ignoreNestedProperties) {
-				name = name.substring(prefixLength);
-				if (!name.contains(".")) {
-					rtn.add(name, pv.getValue());
-				}
-			}
-			else {
 			for (String candidate : new RelaxedNames(this.namePrefix)) {
 				if (name.startsWith(candidate)) {
 					name = name.substring(candidate.length());
+					if (!(this.ignoreNestedProperties && name.contains("."))) {
 						rtn.add(name, pv.getValue());
 					}
 				}

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

@@ -43,7 +43,7 @@ public final class RelaxedNames implements Iterable<String> {
 	 * using dashed notation (e.g. {@literal my-property-name}
 	 */
 	public RelaxedNames(String name) {
-		this.name = name;
+		this.name = name == null ? "" : name;
 		initialize(RelaxedNames.this.name, this.values);
 	}
 
@@ -103,6 +103,12 @@ public final class RelaxedNames implements Iterable<String> {
 				return value.replace("-", "_");
 			}
 		},
+		UNDERSCORE_TO_PERIOD {
+			@Override
+			public String apply(String value) {
+				return value.replace("_", ".");
+			}
+		},
 		PERIOD_TO_UNDERSCORE {
 			@Override
 			public String apply(String value) {

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

@@ -109,6 +109,13 @@ public class RelaxedDataBinderTests {
 		assertEquals("bar", target.getFoo_bar());
 	}
 
+	@Test
+	public void testBindUnderscoreToCamelCase() throws Exception {
+		VanillaTarget target = new VanillaTarget();
+		bind(target, "foo_baz: bar");
+		assertEquals("bar", target.getFooBaz());
+	}
+
 	@Test
 	public void testBindHyphen() throws Exception {
 		VanillaTarget target = new VanillaTarget();
@@ -119,7 +126,7 @@ public class RelaxedDataBinderTests {
 	@Test
 	public void testBindCamelCase() throws Exception {
 		VanillaTarget target = new VanillaTarget();
-		bind(target, "foo-baz: bar");
+		bind(target, "fooBaz: bar");
 		assertEquals("bar", target.getFooBaz());
 	}
 
@@ -182,6 +189,13 @@ public class RelaxedDataBinderTests {
 		assertEquals(123, target.getNested().getValue());
 	}
 
+	@Test
+	public void testBindNestedWithEnviromentStyle() throws Exception {
+		TargetWithNestedObject target = new TargetWithNestedObject();
+		bind(target, "nested_foo: bar\n" + "nested_value: 123");
+		assertEquals(123, target.getNested().getValue());
+	}
+
 	@Test
 	public void testBindNestedList() throws Exception {
 		TargetWithNestedList target = new TargetWithNestedList();

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

@@ -50,9 +50,11 @@ public class RelaxedNamesTests {
 	public void fromUnderscores() throws Exception {
 		Iterator<String> iterator = new RelaxedNames("nes_ted").iterator();
 		assertThat(iterator.next(), equalTo("nes_ted"));
+		assertThat(iterator.next(), equalTo("nes.ted"));
 		assertThat(iterator.next(), equalTo("nesTed"));
 		assertThat(iterator.next(), equalTo("nested"));
 		assertThat(iterator.next(), equalTo("NES_TED"));
+		assertThat(iterator.next(), equalTo("NES.TED"));
 		assertThat(iterator.next(), equalTo("NESTED"));
 		assertThat(iterator.hasNext(), equalTo(false));
 	}
@@ -99,4 +101,11 @@ public class RelaxedNamesTests {
 		assertThat(iterator.hasNext(), equalTo(false));
 	}
 
+	@Test
+	public void fromEmpty() throws Exception {
+		Iterator<String> iterator = new RelaxedNames("").iterator();
+		assertThat(iterator.next(), equalTo(""));
+		assertThat(iterator.hasNext(), equalTo(false));
+	}
+
 }

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

@@ -22,6 +22,7 @@ import java.util.List;
 
 import javax.annotation.PostConstruct;
 
+import org.junit.After;
 import org.junit.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.TestUtils;
@@ -43,6 +44,13 @@ public class EnableConfigurationPropertiesTests {
 
 	private AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
 
+	@After
+	public void close() {
+		System.clearProperty("name");
+		System.clearProperty("nested.name");
+		System.clearProperty("nested_name");
+	}
+
 	@Test
 	public void testBasicPropertiesBinding() {
 		this.context.register(TestConfiguration.class);
@@ -52,6 +60,37 @@ public class EnableConfigurationPropertiesTests {
 		assertEquals("foo", this.context.getBean(TestProperties.class).name);
 	}
 
+	@Test
+	public void testSystemPropertiesBinding() {
+		this.context.register(TestConfiguration.class);
+		System.setProperty("name", "foo");
+		this.context.refresh();
+		assertEquals(1, this.context.getBeanNamesForType(TestProperties.class).length);
+		assertEquals("foo", this.context.getBean(TestProperties.class).name);
+	}
+
+	@Test
+	public void testNestedSystemPropertiesBinding() {
+		this.context.register(NestedConfiguration.class);
+		System.setProperty("name", "foo");
+		System.setProperty("nested.name", "bar");
+		this.context.refresh();
+		assertEquals(1, this.context.getBeanNamesForType(NestedProperties.class).length);
+		assertEquals("foo", this.context.getBean(NestedProperties.class).name);
+		assertEquals("bar", this.context.getBean(NestedProperties.class).nested.name);
+	}
+
+	@Test
+	public void testNestedSystemPropertiesBindingWithUnderscore() {
+		this.context.register(NestedConfiguration.class);
+		System.setProperty("name", "foo");
+		System.setProperty("nested_name", "bar");
+		this.context.refresh();
+		assertEquals(1, this.context.getBeanNamesForType(NestedProperties.class).length);
+		assertEquals("foo", this.context.getBean(NestedProperties.class).name);
+		assertEquals("bar", this.context.getBean(NestedProperties.class).nested.name);
+	}
+
 	@Test
 	public void testStrictPropertiesBinding() {
 		this.context.register(StrictTestConfiguration.class);