Restructor and improve Origin support

Move the `Origin` and related classes from `o.s.boot.env` to
`o.s.boot.orgin` and extend support. The concept of an origin can now
be used outside of just the Spring Environment abstraction.

Closes gh-9001

spring-boot/src/main/java/org/springframework/boot/env/OriginCapablePropertySource.java

@@ -1,39 +0,0 @@
-/*
- * Copyright 2012-2017 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.boot.env;
-
-import org.springframework.core.env.PropertySource;
-
-/**
- * An additional interface that may be implemented by a {@link PropertySource} that can
- * return origin information. For example a property source that's backed by a file may
- * return origin information for line and column numbers.
- *
- * @author Phillip Webb
- * @since 2.0.0
- */
-public interface OriginCapablePropertySource {
-
-	/**
-	 * Return the origin of the given property name or {@code null} if the origin cannot
-	 * be determined.
-	 * @param name the property name
-	 * @return the origin of the property or {@code null}
-	 */
-	PropertyOrigin getPropertyOrigin(String name);
-
-}

spring-boot/src/main/java/org/springframework/boot/env/OriginTrackedMapPropertySource.java

@@ -18,18 +18,21 @@ package org.springframework.boot.env;
 
 import java.util.Map;
 
+import org.springframework.boot.origin.Origin;
+import org.springframework.boot.origin.OriginLookup;
+import org.springframework.boot.origin.OriginTrackedValue;
 import org.springframework.core.env.MapPropertySource;
 
 /**
- * {@link OriginCapablePropertySource} backed by a {@link Map} containing
+ * {@link OriginLookup} backed by a {@link Map} containing {@link OriginTrackedValue
- * {@link OriginTrackedValue OriginTrackedValues}.
+ * OriginTrackedValues}.
  *
  * @author Madhura Bhave
  * @author Phillip Webb
  * @see OriginTrackedValue
  */
 class OriginTrackedMapPropertySource extends MapPropertySource
-		implements OriginCapablePropertySource {
+		implements OriginLookup<String> {
 
 	@SuppressWarnings({ "unchecked", "rawtypes" })
 	OriginTrackedMapPropertySource(String name, Map source) {
@@ -46,7 +49,7 @@ class OriginTrackedMapPropertySource extends MapPropertySource
 	}
 
 	@Override
-	public PropertyOrigin getPropertyOrigin(String name) {
+	public Origin getOrigin(String name) {
 		Object value = super.getProperty(name);
 		if (value instanceof OriginTrackedValue) {
 			return ((OriginTrackedValue) value).getOrigin();

spring-boot/src/main/java/org/springframework/boot/env/OriginTrackedPropertiesLoader.java

@@ -23,7 +23,10 @@ import java.io.LineNumberReader;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
-import org.springframework.boot.env.TextResourcePropertyOrigin.Location;
+import org.springframework.boot.origin.Origin;
+import org.springframework.boot.origin.OriginTrackedValue;
+import org.springframework.boot.origin.TextResourceOrigin;
+import org.springframework.boot.origin.TextResourceOrigin.Location;
 import org.springframework.core.io.Resource;
 import org.springframework.util.Assert;
 
@@ -129,7 +132,7 @@ class OriginTrackedPropertiesLoader {
 			buffer.append(reader.getCharacter());
 			reader.read();
 		}
-		PropertyOrigin origin = new TextResourcePropertyOrigin(this.resource, location);
+		Origin origin = new TextResourceOrigin(this.resource, location);
 		return OriginTrackedValue.of(buffer.toString().trim(), origin);
 	}
 

spring-boot/src/main/java/org/springframework/boot/env/OriginTrackedYamlLoader.java

@@ -37,7 +37,10 @@ import org.yaml.snakeyaml.representer.Representer;
 import org.yaml.snakeyaml.resolver.Resolver;
 
 import org.springframework.beans.factory.config.YamlProcessor;
-import org.springframework.boot.env.TextResourcePropertyOrigin.Location;
+import org.springframework.boot.origin.Origin;
+import org.springframework.boot.origin.OriginTrackedValue;
+import org.springframework.boot.origin.TextResourceOrigin;
+import org.springframework.boot.origin.TextResourceOrigin.Location;
 import org.springframework.boot.yaml.SpringProfileDocumentMatcher;
 import org.springframework.core.io.Resource;
 
@@ -106,14 +109,14 @@ class OriginTrackedYamlLoader extends YamlProcessor {
 		}
 
 		private Object constructTrackedObject(Node node, Object value) {
-			PropertyOrigin origin = getOrigin(node);
+			Origin origin = getOrigin(node);
 			return OriginTrackedValue.of(value, origin);
 		}
 
-		private PropertyOrigin getOrigin(Node node) {
+		private Origin getOrigin(Node node) {
 			Mark mark = node.getStartMark();
 			Location location = new Location(mark.getLine(), mark.getColumn());
-			return new TextResourcePropertyOrigin(OriginTrackedYamlLoader.this.resource,
+			return new TextResourceOrigin(OriginTrackedYamlLoader.this.resource,
 					location);
 		}
 

spring-boot/src/main/java/org/springframework/boot/env/PropertySourcesLoader.java

@@ -33,8 +33,8 @@ import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
 /**
- * Utility that can be used update {@link MutablePropertySources} using
+ * Utility that can be used to update {@link MutablePropertySources} using
- * {@link PropertySourceLoader}s.
+ * {@link PropertySourceLoader PropertySourceLoaders}.
  *
  * @author Phillip Webb
  */

spring-boot/src/main/java/org/springframework/boot/origin/Origin.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2012-2017 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.boot.origin;
+
+import java.io.File;
+
+/**
+ * Interface that uniquely represents the origin of an item. For example, a item loaded
+ * from a {@link File} may have an origin made up of the file name along with line/column
+ * numbers.
+ * <p>
+ * Implementations must provide sensible {@code hashCode()}, {@code equals(...)} and
+ * {@code #toString()} implementations.
+ *
+ * @author Madhura Bhave
+ * @author Phillip Webb
+ * @since 2.0.0
+ * @see OriginProvider
+ */
+public interface Origin {
+
+	/**
+	 * Find the {@link Origin} that an object originated from. Checks if the source object
+	 * is a {@link OriginProvider} and also searches exception stacks.
+	 * @param source the source object or {@code null}
+	 * @return an optional {@link Origin}
+	 */
+	static Origin from(Object source) {
+		if (source instanceof Origin) {
+			return (Origin) source;
+		}
+		Origin origin = null;
+		if (source != null && source instanceof OriginProvider) {
+			origin = ((OriginProvider) source).getOrigin();
+		}
+		if (origin == null && source != null && source instanceof Throwable) {
+			return from(((Throwable) source).getCause());
+		}
+		return origin;
+	}
+
+}

spring-boot/src/main/java/org/springframework/boot/origin/OriginLookup.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2012-2017 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.boot.origin;
+
+/**
+ * An interface that may be implemented by an object that can lookup {@link Origin}
+ * information from a given key. Can be used to add origin support to existing classes.
+ *
+ * @param <K> The lookup key type
+ * @author Phillip Webb
+ * @since 2.0.0
+ */
+public interface OriginLookup<K> {
+
+	/**
+	 * Return the origin of the given key or {@code null} if the origin cannot be
+	 * determined.
+	 * @param key the key to lookup
+	 * @return the origin of the key or {@code null}
+	 */
+	Origin getOrigin(K key);
+
+	/**
+	 * Attempt to lookup the origin from the given source. If the source is not a
+	 * {@link OriginLookup} or if an exception occurs during lookup then {@code null} is
+	 * returned.
+	 * @param source the source object
+	 * @param key the key to lookup
+	 * @param <K> the key type
+	 * @return an {@link Origin} or {@code null}
+	 */
+	@SuppressWarnings("unchecked")
+	static <K> Origin getOrigin(Object source, K key) {
+		if (!(source instanceof OriginLookup)) {
+			return null;
+		}
+		try {
+			return ((OriginLookup<K>) source).getOrigin(key);
+		}
+		catch (Throwable ex) {
+			return null;
+		}
+	}
+
+}

spring-boot/src/main/java/org/springframework/boot/origin/OriginProvider.java

@@ -14,22 +14,21 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.env;
+package org.springframework.boot.origin;
-
-import java.io.File;
 
 /**
- * Interface that uniquely represents the origin of a property. For example, a property
+ * Interface to provide access to the origin of an item.
- * loaded from a {@link File} may have an origin made up of the file name along with
- * line/column numbers.
- * <p>
- * Implementations must provide sensible {@code hashCode()}, {@code equals(...)} and
- * {@code #toString()} implementations.
  *
- * @author Madhura Bhave
  * @author Phillip Webb
  * @since 2.0.0
+ * @see Origin
  */
-public interface PropertyOrigin {
+public interface OriginProvider {
+
+	/**
+	 * Return the source origin or {@code null} if the origin is not known.
+	 * @return the origin or {@code null}
+	 */
+	Origin getOrigin();
 
 }

spring-boot/src/main/java/org/springframework/boot/origin/OriginTrackedValue.java

@@ -14,41 +14,51 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.env;
+package org.springframework.boot.origin;
+
+import org.springframework.util.ObjectUtils;
 
 /**
- * Wrapper class for an Object {@code value} and {@link PropertyOrigin origin}.
+ * An wrapper for a {@link Object} value and {@link Origin}.
  *
  * @author Madhura Bhave
- * @see OriginTrackedMapPropertySource
+ * @author Phillip Webb
+ * @since 2.0.0
+ * @see #of(Object)
+ * @see #of(Object, Origin)
  */
-class OriginTrackedValue {
+public class OriginTrackedValue implements OriginProvider {
 
 	private final Object value;
 
-	private final PropertyOrigin origin;
+	private final Origin origin;
 
-	OriginTrackedValue(Object value, PropertyOrigin origin) {
+	private OriginTrackedValue(Object value, Origin origin) {
 		this.value = value;
 		this.origin = origin;
 	}
 
+	/**
+	 * Return the tracked value.
+	 * @return the tracked value
+	 */
 	public Object getValue() {
 		return this.value;
 	}
 
-	public PropertyOrigin getOrigin() {
+	@Override
+	public Origin getOrigin() {
 		return this.origin;
 	}
 
 	@Override
 	public String toString() {
-		return this.value.toString();
+		return (this.value == null ? null : this.value.toString());
 	}
 
 	@Override
 	public int hashCode() {
-		return this.value.hashCode();
+		return ObjectUtils.nullSafeHashCode(this.value);
 	}
 
 	@Override
@@ -56,7 +66,11 @@ class OriginTrackedValue {
 		if (obj == null || obj.getClass() != getClass()) {
 			return false;
 		}
-		return this.value.equals(((OriginTrackedValue) obj).value);
+		return ObjectUtils.nullSafeEquals(this.value, ((OriginTrackedValue) obj).value);
+	}
+
+	public static OriginTrackedValue of(Object value) {
+		return of(value, null);
 	}
 
 	/**
@@ -65,10 +79,10 @@ class OriginTrackedValue {
 	 * the resulting {@link OriginTrackedValue}.
 	 * @param value the source value
 	 * @param origin the origin
-	 * @return an {@link OriginTrackedValue} or {@code null} if the source value was
+	 * @return a {@link OriginTrackedValue} or {@code null} if the source value was
 	 * {@code null}.
 	 */
-	public static OriginTrackedValue of(Object value, PropertyOrigin origin) {
+	public static OriginTrackedValue of(Object value, Origin origin) {
 		if (value == null) {
 			return null;
 		}
@@ -84,7 +98,7 @@ class OriginTrackedValue {
 	private static class OriginTrackedCharSequence extends OriginTrackedValue
 			implements CharSequence {
 
-		OriginTrackedCharSequence(CharSequence value, PropertyOrigin origin) {
+		OriginTrackedCharSequence(CharSequence value, Origin origin) {
 			super(value, origin);
 		}
 

spring-boot/src/main/java/org/springframework/boot/origin/PropertySourceOrigin.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2012-2017 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.boot.origin;
+
+import org.springframework.core.env.PropertySource;
+import org.springframework.util.Assert;
+
+/**
+ * {@link Origin} from a {@link PropertySource}.
+ *
+ * @author Phillip Webb
+ * @since 2.0.0
+ */
+public class PropertySourceOrigin implements Origin {
+
+	private final PropertySource<?> propertySource;
+
+	private final String propertyName;
+
+	/**
+	 * Create a new {@link PropertySourceOrigin} instance.
+	 * @param propertySource the origin property source
+	 * @param propertyName the origin property name
+	 */
+	public PropertySourceOrigin(PropertySource<?> propertySource, String propertyName) {
+		Assert.notNull(propertySource, "PropertySource must not be null");
+		Assert.hasLength(propertyName, "PropertyName must not be empty");
+		this.propertySource = propertySource;
+		this.propertyName = propertyName;
+	}
+
+	/**
+	 * Return the origin {@link PropertySource}.
+	 * @return the origin property source
+	 */
+	public PropertySource<?> getPropertySource() {
+		return this.propertySource;
+	}
+
+	/**
+	 * Return the origin property name.
+	 * @return the origin property name
+	 */
+	public String getPropertyName() {
+		return this.propertyName;
+	}
+
+	@Override
+	public String toString() {
+		return "\"" + this.propertyName + "\" from property source \""
+				+ this.propertySource.getName() + "\"";
+	}
+
+	/**
+	 * Get a {@link Origin} for the given {@link PropertySource} and {@code propertyName}.
+	 * Will either return an {@link OriginLookup} result or a
+	 * {@link PropertySourceOrigin}.
+	 * @param propertySource the origin property source
+	 * @param name the property name
+	 * @return the property origin
+	 */
+	public static Origin get(PropertySource<?> propertySource, String name) {
+		Origin origin = OriginLookup.getOrigin(propertySource, name);
+		return (origin != null ? origin : new PropertySourceOrigin(propertySource, name));
+	}
+
+}

spring-boot/src/main/java/org/springframework/boot/origin/TextResourceOrigin.java

@@ -14,26 +14,26 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.env;
+package org.springframework.boot.origin;
 
 import org.springframework.core.io.Resource;
 import org.springframework.util.ObjectUtils;
 
 /**
- * {@link PropertyOrigin} for an item loaded from a text resource. Provides access to the
+ * {@link Origin} for an item loaded from a text resource. Provides access to the
  * original {@link Resource} that loaded the text and a {@link Location} within it.
  *
  * @author Madhura Bhave
  * @author Phillip Webb
  * @since 2.0.0
  */
-public class TextResourcePropertyOrigin implements PropertyOrigin {
+public class TextResourceOrigin implements Origin {
 
 	private final Resource resource;
 
 	private final Location location;
 
-	public TextResourcePropertyOrigin(Resource resource, Location location) {
+	public TextResourceOrigin(Resource resource, Location location) {
 		this.resource = resource;
 		this.location = location;
 	}
@@ -70,8 +70,8 @@ public class TextResourcePropertyOrigin implements PropertyOrigin {
 		if (obj == null) {
 			return false;
 		}
-		if (obj instanceof TextResourcePropertyOrigin) {
+		if (obj instanceof TextResourceOrigin) {
-			TextResourcePropertyOrigin other = (TextResourcePropertyOrigin) obj;
+			TextResourceOrigin other = (TextResourceOrigin) obj;
 			boolean result = true;
 			result = result && ObjectUtils.nullSafeEquals(this.resource, other.resource);
 			result = result && ObjectUtils.nullSafeEquals(this.location, other.location);

spring-boot/src/main/java/org/springframework/boot/origin/package-info.java

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2012-2017 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.
+ */
+
+/**
+ * Support for item origin tracking.
+ * @see org.springframework.boot.origin.Origin
+ */
+package org.springframework.boot.origin;

spring-boot/src/test/java/org/springframework/boot/env/OriginTrackedMapPropertySourceTests.java

@@ -21,6 +21,9 @@ import java.util.Map;
 
 import org.junit.Test;
 
+import org.springframework.boot.origin.Origin;
+import org.springframework.boot.origin.OriginTrackedValue;
+
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 
@@ -37,7 +40,7 @@ public class OriginTrackedMapPropertySourceTests {
 	private OriginTrackedMapPropertySource source = new OriginTrackedMapPropertySource(
 			"test", this.map);
 
-	private PropertyOrigin origin = mock(PropertyOrigin.class);
+	private Origin origin = mock(Origin.class);
 
 	@Test
 	public void getPropertyWhenMissingShouldReturnNull() throws Exception {
@@ -52,25 +55,25 @@ public class OriginTrackedMapPropertySourceTests {
 
 	@Test
 	public void getPropertyWhenTrackedShouldReturnValue() throws Exception {
-		this.map.put("test", new OriginTrackedValue("foo", this.origin));
+		this.map.put("test", OriginTrackedValue.of("foo", this.origin));
 		assertThat(this.source.getProperty("test")).isEqualTo("foo");
 	}
 
 	@Test
 	public void getPropertyOriginWhenMissingShouldReturnNull() throws Exception {
-		assertThat(this.source.getPropertyOrigin("test")).isNull();
+		assertThat(this.source.getOrigin("test")).isNull();
 	}
 
 	@Test
 	public void getPropertyOriginWhenNonTrackedShouldReturnNull() throws Exception {
 		this.map.put("test", "foo");
-		assertThat(this.source.getPropertyOrigin("test")).isNull();
+		assertThat(this.source.getOrigin("test")).isNull();
 	}
 
 	@Test
 	public void getPropertyOriginWhenTrackedShouldReturnOrigin() throws Exception {
-		this.map.put("test", new OriginTrackedValue("foo", this.origin));
+		this.map.put("test", OriginTrackedValue.of("foo", this.origin));
-		assertThat(this.source.getPropertyOrigin("test")).isEqualTo(this.origin);
+		assertThat(this.source.getOrigin("test")).isEqualTo(this.origin);
 	}
 
 }

spring-boot/src/test/java/org/springframework/boot/env/OriginTrackedPropertiesLoaderTests.java

@@ -22,6 +22,8 @@ import java.util.Properties;
 import org.junit.Before;
 import org.junit.Test;
 
+import org.springframework.boot.origin.OriginTrackedValue;
+import org.springframework.boot.origin.TextResourceOrigin;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.support.PropertiesLoaderUtils;
 
@@ -234,7 +236,8 @@ public class OriginTrackedPropertiesLoaderTests {
 		if (value == null) {
 			return null;
 		}
-		return ((TextResourcePropertyOrigin) value.getOrigin()).getLocation().toString();
+		return ((TextResourceOrigin) value.getOrigin()).getLocation()
+				.toString();
 	}
 
 }

spring-boot/src/test/java/org/springframework/boot/env/OriginTrackedYamlLoaderTests.java

@@ -21,6 +21,8 @@ import java.util.Map;
 import org.junit.Before;
 import org.junit.Test;
 
+import org.springframework.boot.origin.OriginTrackedValue;
+import org.springframework.boot.origin.TextResourceOrigin;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
 
@@ -120,7 +122,8 @@ public class OriginTrackedYamlLoaderTests {
 	}
 
 	private String getLocation(OriginTrackedValue value) {
-		return ((TextResourcePropertyOrigin) value.getOrigin()).getLocation().toString();
+		return ((TextResourceOrigin) value.getOrigin()).getLocation()
+				.toString();
 	}
 
 }

spring-boot/src/test/java/org/springframework/boot/origin/MockOrigin.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2012-2017 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.boot.origin;
+
+import org.springframework.util.Assert;
+
+/**
+ * Mock {@link Origin} implementation used for testing.
+ *
+ * @author Phillip Webb
+ */
+public final class MockOrigin implements Origin {
+
+	private final String value;
+
+	private MockOrigin(String value) {
+		Assert.notNull(value, "Value must not be null");
+		this.value = value;
+	}
+
+	@Override
+	public int hashCode() {
+		return this.value.hashCode();
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (obj == null || getClass() != obj.getClass()) {
+			return false;
+		}
+		return this.value.equals(((MockOrigin) obj).value);
+	}
+
+	@Override
+	public String toString() {
+		return this.value;
+	}
+
+	public static Origin of(String value) {
+		return (value == null ? null : new MockOrigin(value));
+	}
+
+}

spring-boot/src/test/java/org/springframework/boot/origin/OriginLookupTests.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2012-2017 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.boot.origin;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.BDDMockito.willThrow;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link OriginLookup}.
+ *
+ * @author Phillip Webb
+ */
+public class OriginLookupTests {
+
+	@Test
+	public void getOriginWhenSourceIsNullShouldReturnNull() throws Exception {
+		assertThat(OriginLookup.getOrigin(null, "foo")).isNull();
+	}
+
+	@Test
+	public void getOriginWhenSourceIsNotLookupShouldReturnLookupOrigin()
+			throws Exception {
+		Object source = new Object();
+		assertThat(OriginLookup.getOrigin(source, "foo")).isNull();
+	}
+
+	@Test
+	@SuppressWarnings("unchecked")
+	public void getOriginWhenSourceIsLookupShouldReturnLookupOrigin() throws Exception {
+		OriginLookup<String> source = mock(OriginLookup.class);
+		Origin origin = MockOrigin.of("bar");
+		given(source.getOrigin("foo")).willReturn(origin);
+		assertThat(OriginLookup.getOrigin(source, "foo")).isEqualTo(origin);
+	}
+
+	@Test
+	@SuppressWarnings("unchecked")
+	public void getOriginWhenSourceLookupThrowsAndErrorShouldReturnNull()
+			throws Exception {
+		OriginLookup<String> source = mock(OriginLookup.class);
+		willThrow(RuntimeException.class).given(source).getOrigin("foo");
+		assertThat(OriginLookup.getOrigin(source, "foo")).isNull();
+	}
+
+}

spring-boot/src/test/java/org/springframework/boot/origin/OriginTests.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright 2012-2017 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.boot.origin;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link Origin}.
+ *
+ * @author Phillip Webb
+ */
+public class OriginTests {
+
+	@Test
+	public void fromWhenSourceIsNullShouldReturnNull() throws Exception {
+		assertThat(Origin.from(null)).isNull();
+	}
+
+	@Test
+	public void fromWhenSourceIsRegularObjectShouldReturnNull() throws Exception {
+		Object source = new Object();
+		assertThat(Origin.from(source)).isNull();
+	}
+
+	@Test
+	public void fromWhenSourceIsOriginShouldReturnSource() throws Exception {
+		Origin origin = mock(Origin.class);
+		assertThat(Origin.from(origin)).isEqualTo(origin);
+	}
+
+	@Test
+	public void fromWhenSourceIsOriginProviderShouldReturnProvidedOrigin()
+			throws Exception {
+		Origin origin = mock(Origin.class);
+		OriginProvider originProvider = mock(OriginProvider.class);
+		given(originProvider.getOrigin()).willReturn(origin);
+		assertThat(Origin.from(origin)).isEqualTo(origin);
+	}
+
+	@Test
+	public void fromWhenSourceIsThrowableShouldUseCause() throws Exception {
+		Origin origin = mock(Origin.class);
+		Exception exception = new RuntimeException(new TestException(origin, null));
+		assertThat(Origin.from(exception)).isEqualTo(origin);
+	}
+
+	@Test
+	public void fromWhenSourceIsThrowableAndOriginProviderThatReturnsNullShouldUseCause()
+			throws Exception {
+		Origin origin = mock(Origin.class);
+		Exception exception = new TestException(null, new TestException(origin, null));
+		assertThat(Origin.from(exception)).isEqualTo(origin);
+	}
+
+	private static class TestException extends RuntimeException
+			implements OriginProvider {
+
+		private final Origin origin;
+
+		TestException(Origin origin, Throwable cause) {
+			super(cause);
+			this.origin = origin;
+		}
+
+		@Override
+		public Origin getOrigin() {
+			return this.origin;
+		}
+
+	}
+
+}

spring-boot/src/test/java/org/springframework/boot/origin/OriginTrackedValueTests.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2012-2017 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.boot.origin;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link OriginTrackedValue}.
+ *
+ * @author Phillip Webb
+ */
+public class OriginTrackedValueTests {
+
+	@Test
+	public void getValueShouldReturnValue() throws Exception {
+		Object value = new Object();
+		assertThat(OriginTrackedValue.of(value).getValue()).isEqualTo(value);
+	}
+
+	@Test
+	public void getOriginShouldReturnOrigin() throws Exception {
+		Object value = new Object();
+		Origin origin = mock(Origin.class);
+		assertThat(OriginTrackedValue.of(value, origin).getOrigin()).isEqualTo(origin);
+	}
+
+	@Test
+	public void toStringShouldReturnValueToString() throws Exception {
+		Object value = new Object();
+		assertThat(OriginTrackedValue.of(value).toString()).isEqualTo(value.toString());
+	}
+
+	@Test
+	public void hashCodeAndEqualsShouldIgnoreOrigin() throws Exception {
+		Object value1 = new Object();
+		OriginTrackedValue tracked1 = OriginTrackedValue.of(value1);
+		OriginTrackedValue tracked2 = OriginTrackedValue.of(value1, mock(Origin.class));
+		OriginTrackedValue tracked3 = OriginTrackedValue.of(new Object());
+		assertThat(tracked1.hashCode()).isEqualTo(tracked2.hashCode());
+		assertThat(tracked1).isEqualTo(tracked1).isEqualTo(tracked2)
+				.isNotEqualTo(tracked3);
+	}
+
+	@Test
+	public void ofWhenValueIsNullShouldReturnNull() throws Exception {
+		assertThat(OriginTrackedValue.of(null)).isNull();
+		assertThat(OriginTrackedValue.of(null, mock(Origin.class))).isNull();
+	}
+
+	@Test
+	public void ofWhenValueIsCharSequenceShouldReturnCharSequence() throws Exception {
+		String value = "foo";
+		OriginTrackedValue tracked = OriginTrackedValue.of(value);
+		assertThat(tracked).isInstanceOf(CharSequence.class);
+		CharSequence charSequence = (CharSequence) tracked;
+		assertThat(charSequence.length()).isEqualTo(value.length());
+		assertThat(charSequence.charAt(0)).isEqualTo(value.charAt(0));
+		assertThat(charSequence.subSequence(0, 1)).isEqualTo(value.subSequence(0, 1));
+	}
+
+}

spring-boot/src/test/java/org/springframework/boot/origin/PropertySourceOriginTests.java

@@ -0,0 +1,114 @@
+/*
+ * Copyright 2012-2017 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.boot.origin;
+
+import java.util.HashMap;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+import org.springframework.core.env.MapPropertySource;
+import org.springframework.core.env.PropertySource;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.withSettings;
+
+/**
+ * Tests for {@link PropertySourceOrigin}.
+ *
+ * @author Phillip Webb
+ */
+public class PropertySourceOriginTests {
+
+	@Rule
+	public ExpectedException thrown = ExpectedException.none();
+
+	@Test
+	public void createWhenPropertySourceIsNullShouldThrowException() {
+		this.thrown.expect(IllegalArgumentException.class);
+		this.thrown.expectMessage("PropertySource must not be null");
+		new PropertySourceOrigin(null, "name");
+	}
+
+	@Test
+	public void createWhenPropertyNameIsNullShouldThrowException() throws Exception {
+		this.thrown.expect(IllegalArgumentException.class);
+		this.thrown.expectMessage("PropertyName must not be empty");
+		new PropertySourceOrigin(mock(PropertySource.class), null);
+	}
+
+	@Test
+	public void createWhenPropertyNameIsEmptyShouldThrowException() throws Exception {
+		this.thrown.expect(IllegalArgumentException.class);
+		this.thrown.expectMessage("PropertyName must not be empty");
+		new PropertySourceOrigin(mock(PropertySource.class), "");
+	}
+
+	@Test
+	public void getPropertySourceShouldReturnPropertySource() throws Exception {
+		MapPropertySource propertySource = new MapPropertySource("test", new HashMap<>());
+		PropertySourceOrigin origin = new PropertySourceOrigin(propertySource, "foo");
+		assertThat(origin.getPropertySource()).isEqualTo(propertySource);
+	}
+
+	@Test
+	public void getPropertyNameShouldReturnPropertyName() throws Exception {
+		MapPropertySource propertySource = new MapPropertySource("test", new HashMap<>());
+		PropertySourceOrigin origin = new PropertySourceOrigin(propertySource, "foo");
+		assertThat(origin.getPropertyName()).isEqualTo("foo");
+	}
+
+	@Test
+	public void toStringShouldShowDetails() throws Exception {
+		MapPropertySource propertySource = new MapPropertySource("test", new HashMap<>());
+		PropertySourceOrigin origin = new PropertySourceOrigin(propertySource, "foo");
+		assertThat(origin.toString()).isEqualTo("\"foo\" from property source \"test\"");
+	}
+
+	@Test
+	@SuppressWarnings("unchecked")
+	public void getWhenPropertySourceSupportsOriginLookupShouldReturnOrigin()
+			throws Exception {
+		Origin origin = mock(Origin.class);
+		PropertySource<?> propertySource = mock(PropertySource.class,
+				withSettings().extraInterfaces(OriginLookup.class));
+		OriginLookup<String> originCapablePropertySource = (OriginLookup<String>) propertySource;
+		given(originCapablePropertySource.getOrigin("foo")).willReturn(origin);
+		assertThat(PropertySourceOrigin.get(propertySource, "foo")).isSameAs(origin);
+	}
+
+	@Test
+	public void getWhenPropertySourceSupportsOriginLookupButNoOriginShouldWrap()
+			throws Exception {
+		PropertySource<?> propertySource = mock(PropertySource.class,
+				withSettings().extraInterfaces(OriginLookup.class));
+		assertThat(PropertySourceOrigin.get(propertySource, "foo"))
+				.isInstanceOf(PropertySourceOrigin.class);
+	}
+
+	@Test
+	public void getWhenPropertySourceIsNotOriginAwareShouldWrap() throws Exception {
+		MapPropertySource propertySource = new MapPropertySource("test", new HashMap<>());
+		PropertySourceOrigin origin = new PropertySourceOrigin(propertySource, "foo");
+		assertThat(origin.getPropertySource()).isEqualTo(propertySource);
+		assertThat(origin.getPropertyName()).isEqualTo("foo");
+	}
+
+}

spring-boot/src/test/java/org/springframework/boot/origin/TextResourceOriginTests.java

@@ -14,47 +14,45 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.env;
+package org.springframework.boot.origin;
 
 import org.junit.Test;
 
-import org.springframework.boot.env.TextResourcePropertyOrigin.Location;
+import org.springframework.boot.origin.TextResourceOrigin.Location;
 import org.springframework.core.io.ClassPathResource;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
- * Tests for {@link TextResourcePropertyOrigin}.
+ * Tests for {@link TextResourceOrigin}.
  *
  * @author Phillip Webb
  */
-public class TextResourcePropertyOriginTests {
+public class TextResourceOriginTests {
 
 	@Test
 	public void createWithNullResourceShouldSetNullResource() throws Exception {
-		TextResourcePropertyOrigin origin = new TextResourcePropertyOrigin(null, null);
+		TextResourceOrigin origin = new TextResourceOrigin(null, null);
 		assertThat(origin.getResource()).isNull();
 	}
 
 	@Test
 	public void createWithNullLocationShouldSetNullLocation() throws Exception {
-		TextResourcePropertyOrigin origin = new TextResourcePropertyOrigin(null, null);
+		TextResourceOrigin origin = new TextResourceOrigin(null, null);
 		assertThat(origin.getLocation()).isNull();
 	}
 
 	@Test
 	public void getResourceShouldReturnResource() throws Exception {
 		ClassPathResource resource = new ClassPathResource("foo.txt");
-		TextResourcePropertyOrigin origin = new TextResourcePropertyOrigin(resource,
+		TextResourceOrigin origin = new TextResourceOrigin(resource, null);
-				null);
 		assertThat(origin.getResource()).isEqualTo(resource);
 	}
 
 	@Test
 	public void getLocationShouldReturnLocation() throws Exception {
 		Location location = new Location(1, 2);
-		TextResourcePropertyOrigin origin = new TextResourcePropertyOrigin(null,
+		TextResourceOrigin origin = new TextResourceOrigin(null, location);
-				location);
 		assertThat(origin.getLocation()).isEqualTo(location);
 
 	}
@@ -81,24 +79,21 @@ public class TextResourcePropertyOriginTests {
 	public void toStringShouldReturnNiceString() throws Exception {
 		ClassPathResource resource = new ClassPathResource("foo.txt");
 		Location location = new Location(1, 2);
-		TextResourcePropertyOrigin origin = new TextResourcePropertyOrigin(resource,
+		TextResourceOrigin origin = new TextResourceOrigin(resource, location);
-				location);
 		assertThat(origin.toString()).isEqualTo("class path resource [foo.txt]:2:3");
 	}
 
 	@Test
 	public void toStringWhenResourceIsNullShouldReturnNiceString() throws Exception {
 		Location location = new Location(1, 2);
-		TextResourcePropertyOrigin origin = new TextResourcePropertyOrigin(null,
+		TextResourceOrigin origin = new TextResourceOrigin(null, location);
-				location);
 		assertThat(origin.toString()).isEqualTo("unknown resource [?]:2:3");
 	}
 
 	@Test
 	public void toStringWhenLocationIsNullShouldReturnNiceString() throws Exception {
 		ClassPathResource resource = new ClassPathResource("foo.txt");
-		TextResourcePropertyOrigin origin = new TextResourcePropertyOrigin(resource,
+		TextResourceOrigin origin = new TextResourceOrigin(resource, null);
-				null);
 		assertThat(origin.toString()).isEqualTo("class path resource [foo.txt]");
 	}
 
@@ -117,13 +112,13 @@ public class TextResourcePropertyOriginTests {
 
 	@Test
 	public void equalsAndHashCodeShouldResourceAndLocation() throws Exception {
-		TextResourcePropertyOrigin origin1 = new TextResourcePropertyOrigin(
+		TextResourceOrigin origin1 = new TextResourceOrigin(
 				new ClassPathResource("foo.txt"), new Location(1, 2));
-		TextResourcePropertyOrigin origin2 = new TextResourcePropertyOrigin(
+		TextResourceOrigin origin2 = new TextResourceOrigin(
 				new ClassPathResource("foo.txt"), new Location(1, 2));
-		TextResourcePropertyOrigin origin3 = new TextResourcePropertyOrigin(
+		TextResourceOrigin origin3 = new TextResourceOrigin(
 				new ClassPathResource("foo.txt"), new Location(2, 2));
-		TextResourcePropertyOrigin origin4 = new TextResourcePropertyOrigin(
+		TextResourceOrigin origin4 = new TextResourceOrigin(
 				new ClassPathResource("foo2.txt"), new Location(1, 2));
 		assertThat(origin1.hashCode()).isEqualTo(origin1.hashCode());
 		assertThat(origin1.hashCode()).isEqualTo(origin2.hashCode());