Consistent Iterator/Stream support in PropertySources and PropertyValues

Issue: SPR-16894

spring-beans/src/main/java/org/springframework/beans/MutablePropertyValues.java

@@ -18,16 +18,21 @@ package org.springframework.beans;
 
 import java.io.Serializable;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashSet;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.Spliterator;
+import java.util.Spliterators;
+import java.util.stream.Stream;
 
 import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 
 /**
- * Default implementation of the {@link PropertyValues} interface.
+ * The default implementation of the {@link PropertyValues} interface.
  * Allows simple manipulation of properties, and provides constructors
  * to support deep copy and construction from a Map.
  *
@@ -244,6 +249,21 @@ public class MutablePropertyValues implements PropertyValues, Serializable {
 	}
 
 
+	@Override
+	public Iterator<PropertyValue> iterator() {
+		return Collections.unmodifiableList(this.propertyValueList).iterator();
+	}
+
+	@Override
+	public Spliterator<PropertyValue> spliterator() {
+		return Spliterators.spliterator(this.propertyValueList, 0);
+	}
+
+	@Override
+	public Stream<PropertyValue> stream() {
+		return this.propertyValueList.stream();
+	}
+
 	@Override
 	public PropertyValue[] getPropertyValues() {
 		return this.propertyValueList.toArray(new PropertyValue[0]);

spring-beans/src/main/java/org/springframework/beans/PropertyValues.java

@@ -16,6 +16,13 @@
 
 package org.springframework.beans;
 
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.Spliterator;
+import java.util.Spliterators;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
 import org.springframework.lang.Nullable;
 
 /**
@@ -27,7 +34,33 @@ import org.springframework.lang.Nullable;
  * @since 13 May 2001
  * @see PropertyValue
  */
-public interface PropertyValues {
+public interface PropertyValues extends Iterable<PropertyValue> {
+
+	/**
+	 * Return an {@link Iterator} over the property values.
+	 * @since 5.1
+	 */
+	@Override
+	default Iterator<PropertyValue> iterator() {
+		return Arrays.asList(getPropertyValues()).iterator();
+	}
+
+	/**
+	 * Return a {@link Spliterator} over the property values.
+	 * @since 5.1
+	 */
+	@Override
+	default Spliterator<PropertyValue> spliterator() {
+		return Spliterators.spliterator(getPropertyValues(), 0);
+	}
+
+	/**
+	 * Return a sequential {@link Stream} containing the property values.
+	 * @since 5.1
+	 */
+	default Stream<PropertyValue> stream() {
+		return StreamSupport.stream(spliterator(), false);
+	}
 
 	/**
 	 * Return an array of the PropertyValue objects held in this object.