Polish (Mutable)PropertySources

* PropertySources is now an Iterable<PropertySource> in favor of
  exposing an asList() method
* Otherwise reduced the set of methods exposed by PropertySources to the
  absolute minimum
* Added Javadoc for both types and all methods

org.springframework.core/src/main/java/org/springframework/core/env/MutablePropertySources.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2011 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.
@@ -16,44 +16,80 @@
 
 package org.springframework.core.env;
 
-import java.util.Collections;
+import java.util.Iterator;
 import java.util.LinkedList;
-import java.util.List;
 
 import org.springframework.util.Assert;
 
-
+/**
+ * Default implementation of the {@link PropertySources} interface.
+ * Allows manipulation of contained property sources and provides constructor
+ * to copying an existing {@code PropertySources} instance.
+ *
+ * <p>Where <em>precedence</em> is mentioned in methods such as {@link #addFirst}
+ * and {@link #addLast}, this is with regard to the order in which property sources
+ * will be searched when resolving a given property with a {@link PropertyResolver}.
+ *
+ * @author Chris Beams
+ * @since 3.1
+ * @see PropertySourcesPropertyResolver
+ */
 public class MutablePropertySources implements PropertySources {
 
-	private final LinkedList<PropertySource<?>> propertySourceList = new LinkedList<PropertySource<?>>();
-
 	static final String NON_EXISTENT_PROPERTY_SOURCE_MESSAGE = "PropertySource named [%s] does not exist";
 	static final String ILLEGAL_RELATIVE_ADDITION_MESSAGE = "PropertySource named [%s] cannot be added relative to itself";
 
+	private final LinkedList<PropertySource<?>> propertySourceList = new LinkedList<PropertySource<?>>();
 
+
+	/**
+	 * Create a new {@link MutablePropertySources} object.
+	 */
 	public MutablePropertySources() {
 	}
 
+	/**
+	 * Create a new {@code MutablePropertySources} from the given propertySources
+	 * object, preserving the original order of contained {@code PropertySource} objects.
+	 */
 	public MutablePropertySources(PropertySources propertySources) {
-		this.addAll(propertySources);
-	}
-
-	public void addAll(PropertySources propertySources) {
-		for (PropertySource<?> propertySource : propertySources.asList()) {
+		for (PropertySource<?> propertySource : propertySources) {
 			this.addLast(propertySource);
 		}
 	}
 
+	public boolean contains(String name) {
+		return this.propertySourceList.contains(PropertySource.named(name));
+	}
+
+	public PropertySource<?> get(String name) {
+		return this.propertySourceList.get(this.propertySourceList.indexOf(PropertySource.named(name)));
+	}
+
+	public Iterator<PropertySource<?>> iterator() {
+		return this.propertySourceList.iterator();
+	}
+
+	/**
+	 * Add the given property source object with highest precedence.
+	 */
 	public void addFirst(PropertySource<?> propertySource) {
 		removeIfPresent(propertySource);
 		this.propertySourceList.addFirst(propertySource);
 	}
 
+	/**
+	 * Add the given property source object with lowest precedence.
+	 */
 	public void addLast(PropertySource<?> propertySource) {
 		removeIfPresent(propertySource);
 		this.propertySourceList.addLast(propertySource);
 	}
 
+	/**
+	 * Add the given property source object with precedence immediately greater
+	 * than the named relative property source.
+	 */
 	public void addBefore(String relativePropertySourceName, PropertySource<?> propertySource) {
 		assertLegalRelativeAddition(relativePropertySourceName, propertySource);
 		removeIfPresent(propertySource);
@@ -61,6 +97,10 @@ public class MutablePropertySources implements PropertySources {
 		addAtIndex(index, propertySource);
 	}
 
+	/**
+	 * Add the given property source object with precedence immediately less than
+	 * than the named relative property source.
+	 */
 	public void addAfter(String relativePropertySourceName, PropertySource<?> propertySource) {
 		assertLegalRelativeAddition(relativePropertySourceName, propertySource);
 		removeIfPresent(propertySource);
@@ -68,56 +108,79 @@ public class MutablePropertySources implements PropertySources {
 		addAtIndex(index+1, propertySource);
 	}
 
+	/**
+	 * Return the precedence of the given property source, {@code -1} if not found.
+	 */
+	public int precedenceOf(PropertySource<?> propertySource) {
+		return this.propertySourceList.indexOf(propertySource);
+	}
+
+	/**
+	 * Remove and return the property source with the given name, {@code null} if not found.
+	 * @param name the name of the property source to find and remove
+	 */
+	public PropertySource<?> remove(String name) {
+		int index = this.propertySourceList.indexOf(PropertySource.named(name));
+		if (index >= 0) {
+			return this.propertySourceList.remove(index);
+		}
+		return null;
+	}
+
+	/**
+	 * Replace the property source with the given name with the given property source object.
+	 * @param name the name of the property source to find and replace
+	 * @param propertySource the replacement property source
+	 * @throws IllegalArgumentException if no property source with the given name is present
+	 * @see #contains
+	 */
+	public void replace(String name, PropertySource<?> propertySource) {
+		int index = assertPresentAndGetIndex(name);
+		this.propertySourceList.set(index, propertySource);
+	}
+
+	/**
+	 * Return the number of {@link PropertySource} objects contained.
+	 */
+	public int size() {
+		return this.propertySourceList.size();
+	}
+
+	/**
+	 * Ensure that the given property source is not being added relative to itself.
+	 */
 	protected void assertLegalRelativeAddition(String relativePropertySourceName, PropertySource<?> propertySource) {
 		String newPropertySourceName = propertySource.getName();
 		Assert.isTrue(!relativePropertySourceName.equals(newPropertySourceName),
 				String.format(ILLEGAL_RELATIVE_ADDITION_MESSAGE, newPropertySourceName));
 	}
 
-	protected void addAtIndex(int index, PropertySource<?> propertySource) {
-		removeIfPresent(propertySource);
-		this.propertySourceList.add(index, propertySource);
-	}
-
+	/**
+	 * Log the removal of the given propertySource if it is present.
+	 */
 	protected void removeIfPresent(PropertySource<?> propertySource) {
 		if (this.propertySourceList.contains(propertySource)) {
+			// TODO SPR-7508: add logging
 			this.propertySourceList.remove(propertySource);
 		}
 	}
 
-	public boolean contains(String propertySourceName) {
-		return propertySourceList.contains(PropertySource.named(propertySourceName));
-	}
-
-	public PropertySource<?> remove(String propertySourceName) {
-		int index = propertySourceList.indexOf(PropertySource.named(propertySourceName));
-		if (index >= 0) {
-			return propertySourceList.remove(index);
-		}
-		return null;
-	}
-
-	public void replace(String propertySourceName, PropertySource<?> propertySource) {
-		int index = assertPresentAndGetIndex(propertySourceName);
-		this.propertySourceList.set(index, propertySource);
+	/**
+	 * Add the given property source at a particular index in the list.
+	 */
+	private void addAtIndex(int index, PropertySource<?> propertySource) {
+		removeIfPresent(propertySource);
+		this.propertySourceList.add(index, propertySource);
 	}
 
-	protected int assertPresentAndGetIndex(String propertySourceName) {
+	/**
+	 * Assert that the named property source is present and return its index.
+	 * @throws IllegalArgumentException if the named property source is not present
+	 */
+	private int assertPresentAndGetIndex(String propertySourceName) {
 		int index = this.propertySourceList.indexOf(PropertySource.named(propertySourceName));
 		Assert.isTrue(index >= 0, String.format(NON_EXISTENT_PROPERTY_SOURCE_MESSAGE, propertySourceName));
 		return index;
 	}
 
-	public int size() {
-		return propertySourceList.size();
-	}
-
-	public List<PropertySource<?>> asList() {
-		return Collections.unmodifiableList(this.propertySourceList);
-	}
-
-	public PropertySource<?> get(String propertySourceName) {
-		return propertySourceList.get(propertySourceList.indexOf(PropertySource.named(propertySourceName)));
-	}
-
 }

org.springframework.core/src/main/java/org/springframework/core/env/PropertySources.java

@@ -16,23 +16,24 @@
 
 package org.springframework.core.env;
 
-import java.util.List;
-
 /**
- * TODO SPR-7508: document
+ * Holder containing one or more {@link PropertySource} objects.
  *
  * @author Chris Beams
  * @since 3.1
  */
-public interface PropertySources {
-
-	PropertySource<?> get(String propertySourceName);
-
-	// TODO make iterable
-	List<PropertySource<?>> asList();
-
-	int size();
-
-	boolean contains(String propertySourceName);
+public interface PropertySources extends Iterable<PropertySource<?>> {
+
+	/**
+	 * Return whether a property source with the given name is contained.
+	 * @param name the {@linkplain PropertySource#getName() name of the property source} to find
+	 */
+	boolean contains(String name);
+
+	/**
+	 * Return the property source with the given name, {@code null} if not found.
+	 * @param name the {@linkplain PropertySource#getName() name of the property source} to find
+	 */
+	PropertySource<?> get(String name);
 
 }

org.springframework.core/src/main/java/org/springframework/core/env/PropertySourcesPropertyResolver.java

@@ -38,7 +38,7 @@ public class PropertySourcesPropertyResolver extends AbstractPropertyResolver {
 	}
 
 	public boolean containsProperty(String key) {
-		for (PropertySource<?> propertySource : this.propertySources.asList()) {
+		for (PropertySource<?> propertySource : this.propertySources) {
 			if (propertySource.getProperty(key) != null) {
 				return true;
 			}
@@ -59,7 +59,7 @@ public class PropertySourcesPropertyResolver extends AbstractPropertyResolver {
 			logger.trace(format("getProperty(\"%s\", %s)", key, targetValueType.getSimpleName()));
 		}
 	
-		for (PropertySource<?> propertySource : this.propertySources.asList()) {
+		for (PropertySource<?> propertySource : this.propertySources) {
 			if (debugEnabled) {
 				logger.debug(format("Searching for key '%s' in [%s]", key, propertySource.getName()));
 			}

org.springframework.core/src/test/java/org/springframework/core/env/DefaultEnvironmentTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2011 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.
@@ -20,8 +20,6 @@ import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.is;
 import static org.junit.Assert.assertThat;
 
-import java.util.List;
-
 import org.junit.Test;
 
 public class DefaultEnvironmentTests {
@@ -29,9 +27,9 @@ public class DefaultEnvironmentTests {
 	@Test
 	public void propertySourceOrder() {
 		ConfigurableEnvironment env = new DefaultEnvironment();
-		List<PropertySource<?>> sources = env.getPropertySources().asList();
+		MutablePropertySources sources = env.getPropertySources();
+		assertThat(sources.precedenceOf(PropertySource.named(DefaultEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME)), equalTo(0));
+		assertThat(sources.precedenceOf(PropertySource.named(DefaultEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME)), equalTo(1));
 		assertThat(sources.size(), is(2));
-		assertThat(sources.get(0).getName(), equalTo(DefaultEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME));
-		assertThat(sources.get(1).getName(), equalTo(DefaultEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME));
 	}
 }

org.springframework.core/src/test/java/org/springframework/core/env/PropertySourcesTests.java

@@ -53,43 +53,43 @@ public class PropertySourcesTests {
 		sources.addAfter("b", new MockPropertySource("c"));
 
 		assertThat(sources.size(), equalTo(5));
-		assertThat(sources.asList().indexOf(PropertySource.named("a")), is(0));
-		assertThat(sources.asList().indexOf(PropertySource.named("b")), is(1));
-		assertThat(sources.asList().indexOf(PropertySource.named("c")), is(2));
-		assertThat(sources.asList().indexOf(PropertySource.named("d")), is(3));
-		assertThat(sources.asList().indexOf(PropertySource.named("f")), is(4));
+		assertThat(sources.precedenceOf(PropertySource.named("a")), is(0));
+		assertThat(sources.precedenceOf(PropertySource.named("b")), is(1));
+		assertThat(sources.precedenceOf(PropertySource.named("c")), is(2));
+		assertThat(sources.precedenceOf(PropertySource.named("d")), is(3));
+		assertThat(sources.precedenceOf(PropertySource.named("f")), is(4));
 
 		sources.addBefore("f", new MockPropertySource("e"));
 		sources.addAfter("f", new MockPropertySource("g"));
 
 		assertThat(sources.size(), equalTo(7));
-		assertThat(sources.asList().indexOf(PropertySource.named("a")), is(0));
-		assertThat(sources.asList().indexOf(PropertySource.named("b")), is(1));
-		assertThat(sources.asList().indexOf(PropertySource.named("c")), is(2));
-		assertThat(sources.asList().indexOf(PropertySource.named("d")), is(3));
-		assertThat(sources.asList().indexOf(PropertySource.named("e")), is(4));
-		assertThat(sources.asList().indexOf(PropertySource.named("f")), is(5));
-		assertThat(sources.asList().indexOf(PropertySource.named("g")), is(6));
+		assertThat(sources.precedenceOf(PropertySource.named("a")), is(0));
+		assertThat(sources.precedenceOf(PropertySource.named("b")), is(1));
+		assertThat(sources.precedenceOf(PropertySource.named("c")), is(2));
+		assertThat(sources.precedenceOf(PropertySource.named("d")), is(3));
+		assertThat(sources.precedenceOf(PropertySource.named("e")), is(4));
+		assertThat(sources.precedenceOf(PropertySource.named("f")), is(5));
+		assertThat(sources.precedenceOf(PropertySource.named("g")), is(6));
 
 		sources.addLast(new MockPropertySource("a"));
 		assertThat(sources.size(), equalTo(7));
-		assertThat(sources.asList().indexOf(PropertySource.named("b")), is(0));
-		assertThat(sources.asList().indexOf(PropertySource.named("c")), is(1));
-		assertThat(sources.asList().indexOf(PropertySource.named("d")), is(2));
-		assertThat(sources.asList().indexOf(PropertySource.named("e")), is(3));
-		assertThat(sources.asList().indexOf(PropertySource.named("f")), is(4));
-		assertThat(sources.asList().indexOf(PropertySource.named("g")), is(5));
-		assertThat(sources.asList().indexOf(PropertySource.named("a")), is(6));
+		assertThat(sources.precedenceOf(PropertySource.named("b")), is(0));
+		assertThat(sources.precedenceOf(PropertySource.named("c")), is(1));
+		assertThat(sources.precedenceOf(PropertySource.named("d")), is(2));
+		assertThat(sources.precedenceOf(PropertySource.named("e")), is(3));
+		assertThat(sources.precedenceOf(PropertySource.named("f")), is(4));
+		assertThat(sources.precedenceOf(PropertySource.named("g")), is(5));
+		assertThat(sources.precedenceOf(PropertySource.named("a")), is(6));
 
 		sources.addFirst(new MockPropertySource("a"));
 		assertThat(sources.size(), equalTo(7));
-		assertThat(sources.asList().indexOf(PropertySource.named("a")), is(0));
-		assertThat(sources.asList().indexOf(PropertySource.named("b")), is(1));
-		assertThat(sources.asList().indexOf(PropertySource.named("c")), is(2));
-		assertThat(sources.asList().indexOf(PropertySource.named("d")), is(3));
-		assertThat(sources.asList().indexOf(PropertySource.named("e")), is(4));
-		assertThat(sources.asList().indexOf(PropertySource.named("f")), is(5));
-		assertThat(sources.asList().indexOf(PropertySource.named("g")), is(6));
+		assertThat(sources.precedenceOf(PropertySource.named("a")), is(0));
+		assertThat(sources.precedenceOf(PropertySource.named("b")), is(1));
+		assertThat(sources.precedenceOf(PropertySource.named("c")), is(2));
+		assertThat(sources.precedenceOf(PropertySource.named("d")), is(3));
+		assertThat(sources.precedenceOf(PropertySource.named("e")), is(4));
+		assertThat(sources.precedenceOf(PropertySource.named("f")), is(5));
+		assertThat(sources.precedenceOf(PropertySource.named("g")), is(6));
 
 		assertEquals(sources.remove("a"), PropertySource.named("a"));
 		assertThat(sources.size(), equalTo(6));
@@ -109,15 +109,15 @@ public class PropertySourcesTests {
 
 		sources.addFirst(new MockPropertySource("a"));
 		assertThat(sources.size(), equalTo(7));
-		assertThat(sources.asList().indexOf(PropertySource.named("a")), is(0));
-		assertThat(sources.asList().indexOf(PropertySource.named("b")), is(1));
-		assertThat(sources.asList().indexOf(PropertySource.named("c")), is(2));
+		assertThat(sources.precedenceOf(PropertySource.named("a")), is(0));
+		assertThat(sources.precedenceOf(PropertySource.named("b")), is(1));
+		assertThat(sources.precedenceOf(PropertySource.named("c")), is(2));
 
 		sources.replace("a", new MockPropertySource("a-replaced"));
 		assertThat(sources.size(), equalTo(7));
-		assertThat(sources.asList().indexOf(PropertySource.named("a-replaced")), is(0));
-		assertThat(sources.asList().indexOf(PropertySource.named("b")), is(1));
-		assertThat(sources.asList().indexOf(PropertySource.named("c")), is(2));
+		assertThat(sources.precedenceOf(PropertySource.named("a-replaced")), is(0));
+		assertThat(sources.precedenceOf(PropertySource.named("b")), is(1));
+		assertThat(sources.precedenceOf(PropertySource.named("c")), is(2));
 
 		sources.replace("a-replaced", new MockPropertySource("a"));
 

org.springframework.integration-tests/src/test/java/org/springframework/core/env/EnvironmentIntegrationTests.java

@@ -438,16 +438,16 @@ public class EnvironmentIntegrationTests {
 
 		// ServletConfig gets precedence
 		assertThat(environment.getProperty("pCommon"), is("pCommonConfigValue"));
-		assertThat(propertySources.asList().indexOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME)),
-				lessThan(propertySources.asList().indexOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME))));
+		assertThat(propertySources.precedenceOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME)),
+				lessThan(propertySources.precedenceOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME))));
 
 		// but all params are available
 		assertThat(environment.getProperty("pContext1"), is("pContext1Value"));
 		assertThat(environment.getProperty("pConfig1"), is("pConfig1Value"));
 
 		// Servlet* PropertySources have precedence over System* PropertySources
-		assertThat(propertySources.asList().indexOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME)),
-				lessThan(propertySources.asList().indexOf(PropertySource.named(DefaultEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME))));
+		assertThat(propertySources.precedenceOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME)),
+				lessThan(propertySources.precedenceOf(PropertySource.named(DefaultEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME))));
 
 		// Replace system properties with a mock property source for convenience
 		MockPropertySource mockSystemProperties = new MockPropertySource(DefaultEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME);
@@ -480,8 +480,8 @@ public class EnvironmentIntegrationTests {
 		assertThat(environment.getProperty("pContext1"), is("pContext1Value"));
 
 		// Servlet* PropertySources have precedence over System* PropertySources
-		assertThat(propertySources.asList().indexOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME)),
-				lessThan(propertySources.asList().indexOf(PropertySource.named(DefaultEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME))));
+		assertThat(propertySources.precedenceOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME)),
+				lessThan(propertySources.precedenceOf(PropertySource.named(DefaultEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME))));
 
 		// Replace system properties with a mock property source for convenience
 		MockPropertySource mockSystemProperties = new MockPropertySource(DefaultEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME);
@@ -515,16 +515,16 @@ public class EnvironmentIntegrationTests {
 
 		// ServletConfig gets precedence
 		assertThat(environment.getProperty("pCommon"), is("pCommonConfigValue"));
-		assertThat(propertySources.asList().indexOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME)),
-				lessThan(propertySources.asList().indexOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME))));
+		assertThat(propertySources.precedenceOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME)),
+				lessThan(propertySources.precedenceOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME))));
 
 		// but all params are available
 		assertThat(environment.getProperty("pContext1"), is("pContext1Value"));
 		assertThat(environment.getProperty("pConfig1"), is("pConfig1Value"));
 
 		// Servlet* PropertySources have precedence over System* PropertySources
-		assertThat(propertySources.asList().indexOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME)),
-				lessThan(propertySources.asList().indexOf(PropertySource.named(DefaultEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME))));
+		assertThat(propertySources.precedenceOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME)),
+				lessThan(propertySources.precedenceOf(PropertySource.named(DefaultEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME))));
 
 		// Replace system properties with a mock property source for convenience
 		MockPropertySource mockSystemProperties = new MockPropertySource(DefaultEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME);

org.springframework.web/src/test/java/org/springframework/web/context/support/DefaultWebEnvironmentTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2011 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.
@@ -20,24 +20,22 @@ import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.is;
 import static org.junit.Assert.assertThat;
 
-import java.util.List;
-
 import org.junit.Test;
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.DefaultEnvironment;
+import org.springframework.core.env.MutablePropertySources;
 import org.springframework.core.env.PropertySource;
 
-
 public class DefaultWebEnvironmentTests {
 
 	@Test
 	public void propertySourceOrder() {
 		ConfigurableEnvironment env = new DefaultWebEnvironment();
-		List<PropertySource<?>> sources = env.getPropertySources().asList();
+		MutablePropertySources sources = env.getPropertySources();
+		assertThat(sources.precedenceOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME)), equalTo(0));
+		assertThat(sources.precedenceOf(PropertySource.named(DefaultWebEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME)), equalTo(1));
+		assertThat(sources.precedenceOf(PropertySource.named(DefaultEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME)), equalTo(2));
+		assertThat(sources.precedenceOf(PropertySource.named(DefaultEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME)), equalTo(3));
 		assertThat(sources.size(), is(4));
-		assertThat(sources.get(0).getName(), equalTo(DefaultWebEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME));
-		assertThat(sources.get(1).getName(), equalTo(DefaultWebEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME));
-		assertThat(sources.get(2).getName(), equalTo(DefaultEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME));
-		assertThat(sources.get(3).getName(), equalTo(DefaultEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME));
 	}
 }