Introduce Stream support in PropertySources

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

@@ -16,12 +16,16 @@
 
 package org.springframework.core.env;
 
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
 import org.springframework.lang.Nullable;
 
 /**
  * Holder containing one or more {@link PropertySource} objects.
  *
  * @author Chris Beams
+ * @author Christoph Dreis
  * @since 3.1
  */
 public interface PropertySources extends Iterable<PropertySource<?>> {
@@ -39,4 +43,12 @@ public interface PropertySources extends Iterable<PropertySource<?>> {
 	@Nullable
 	PropertySource<?> get(String name);
 
+	/**
+	 * Returns a sequential {@code Stream} for the {@link PropertySource objects}
+	 * contained in this instance.
+	 */
+	default Stream<PropertySource<?>> stream() {
+		return StreamSupport.stream(spliterator(), false);
+	}
+
 }

spring-core/src/test/java/org/springframework/core/env/MutablePropertySourcesTests.java

@@ -26,6 +26,7 @@
 /**
  * @author Chris Beams
  * @author Juergen Hoeller
+ * @author Christoph Dreis
  */
 public class MutablePropertySourcesTests {
 
@@ -153,4 +154,23 @@ public void getNonExistentPropertySourceReturnsNull() {
 		assertThat(sources.get("bogus"), nullValue());
 	}
 
+	@Test
+	public void streamContainsPropertySource() {
+		MutablePropertySources sources = new MutablePropertySources();
+		sources.addLast(new MockPropertySource("test"));
+		assertThat(sources.stream(), notNullValue());
+		assertThat(sources.stream().count(), is(1L));
+		assertThat(sources.stream().anyMatch(source ->
+				source.getName().equals("test")), is(true));
+		assertThat(sources.stream().anyMatch(source ->
+				source.getName().equals("bogus")), is(false));
+	}
+
+	@Test
+	public void streamIsNotNullForEmptySources() {
+		MutablePropertySources sources = new MutablePropertySources();
+		assertThat(sources.stream(), notNullValue());
+		assertThat(sources.stream().count(), is(0L));
+	}
+
 }