Fix SpEL collection selection/projection examples in reference manual

This commit also updates and polishes the documentation tests.

Author: sbrannen

framework-docs/modules/ROOT/pages/core/expressions/language-ref/collection-projection.adoc

@@ -13,16 +13,18 @@ Java::
 +
 [source,java,indent=0,subs="verbatim,quotes",role="primary"]
 ----
-	// returns ['Smiljan', 'Idvor' ]
-	List placesOfBirth = (List)parser.parseExpression("members.![placeOfBirth.city]");
+	// evaluates to ["SmilJan", "Idvor"]
+	List placesOfBirth = parser.parseExpression("members.![placeOfBirth.city]")
+			.getValue(societyContext, List.class);
 ----
 
 Kotlin::
 +
 [source,kotlin,indent=0,subs="verbatim,quotes",role="secondary"]
 ----
-	// returns ['Smiljan', 'Idvor' ]
-	val placesOfBirth = parser.parseExpression("members.![placeOfBirth.city]") as List<*>
+	// evaluates to ["SmilJan", "Idvor"]
+	val placesOfBirth = parser.parseExpression("members.![placeOfBirth.city]")
+	 		.getValue(societyContext) as List<*>
 ----
 ======
 

framework-docs/modules/ROOT/pages/core/expressions/language-ref/collection-selection.adoc

@@ -28,35 +28,36 @@ Kotlin::
 ======
 
 Selection is supported for arrays and anything that implements `java.lang.Iterable` or
-`java.util.Map`. For a list or array, the selection criteria is evaluated against each
-individual element. Against a map, the selection criteria is evaluated against each map
-entry (objects of the Java type `Map.Entry`). Each map entry has its `key` and `value`
-accessible as properties for use in the selection.
+`java.util.Map`. For an array or `Iterable`, the selection expression is evaluated
+against each individual element. Against a map, the selection expression is evaluated
+against each map entry (objects of the Java type `Map.Entry`). Each map entry has its
+`key` and `value` accessible as properties for use in the selection.
 
-The following expression returns a new map that consists of those elements of the
-original map where the entry's value is less than 27:
+Given a `Map` stored in a variable named `#map`, the following expression returns a new
+map that consists of those elements of the original map where the entry's value is less
+than 27:
 
 [tabs]
 ======
 Java::
 +
 [source,java,indent=0,subs="verbatim,quotes",role="primary"]
 ----
-	Map newMap = parser.parseExpression("map.?[value<27]").getValue();
+	Map newMap = parser.parseExpression("#map.?[value < 27]").getValue(Map.class);
 ----
 
 Kotlin::
 +
 [source,kotlin,indent=0,subs="verbatim,quotes",role="secondary"]
 ----
-	val newMap = parser.parseExpression("map.?[value<27]").getValue()
+	val newMap = parser.parseExpression("#map.?[value < 27]").getValue() as Map
 ----
 ======
 
 In addition to returning all the selected elements, you can retrieve only the first or
-the last element. To obtain the first element matching the selection, the syntax is
-`.^[selectionExpression]`. To obtain the last matching selection, the syntax is
-`.$[selectionExpression]`.
+the last element. To obtain the first element matching the selection expression, the
+syntax is `.^[selectionExpression]`. To obtain the last element matching the selection
+expression, the syntax is `.$[selectionExpression]`.
 
 
 

spring-expression/src/test/java/org/springframework/expression/spel/SpelDocumentationTests.java

@@ -22,7 +22,6 @@
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.GregorianCalendar;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -172,28 +171,24 @@ void propertyAccess() {
 		@Test
 		void propertyNavigation() {
 			ExpressionParser parser = new SpelExpressionParser();
-
-			// Inventions Array
 			StandardEvaluationContext teslaContext = TestScenarioCreator.getTestEvaluationContext();
-			// teslaContext.setRootObject(tesla);
 
+			// Inventions Array
 			// evaluates to "Induction motor"
 			String invention = parser.parseExpression("inventions[3]").getValue(teslaContext, String.class);
 			assertThat(invention).isEqualTo("Induction motor");
 
 			// Members List
 			StandardEvaluationContext societyContext = new StandardEvaluationContext();
-			IEEE ieee = new IEEE();
-			ieee.Members[0]= tesla;
-			societyContext.setRootObject(ieee);
+			societyContext.setRootObject(new IEEE());
 
 			// evaluates to "Nikola Tesla"
-			String name = parser.parseExpression("Members[0].Name").getValue(societyContext, String.class);
+			String name = parser.parseExpression("members[0].Name").getValue(societyContext, String.class);
 			assertThat(name).isEqualTo("Nikola Tesla");
 
 			// List and Array navigation
 			// evaluates to "Wireless communication"
-			invention = parser.parseExpression("Members[0].Inventions[6]").getValue(societyContext, String.class);
+			invention = parser.parseExpression("members[0].Inventions[6]").getValue(societyContext, String.class);
 			assertThat(invention).isEqualTo("Wireless communication");
 		}
 
@@ -210,12 +205,12 @@ void maps() {
 			assertThat(city).isNotNull();
 
 			// setting values
-			Inventor i = parser.parseExpression("officers['advisors'][0]").getValue(societyContext,Inventor.class);
+			Inventor i = parser.parseExpression("officers['advisors'][0]").getValue(societyContext, Inventor.class);
 			assertThat(i.getName()).isEqualTo("Nikola Tesla");
 
 			parser.parseExpression("officers['advisors'][0].PlaceOfBirth.Country").setValue(societyContext, "Croatia");
 
-			Inventor i2 = parser.parseExpression("reverse[0]['advisors'][0]").getValue(societyContext,Inventor.class);
+			Inventor i2 = parser.parseExpression("reverse[0]['advisors'][0]").getValue(societyContext, Inventor.class);
 			assertThat(i2.getName()).isEqualTo("Nikola Tesla");
 		}
 	}
@@ -489,7 +484,7 @@ void constructors() {
 					parser.parseExpression("new org.springframework.expression.spel.testresources.Inventor('Albert Einstein',new java.util.Date(), 'German')").getValue(Inventor.class);
 			assertThat(einstein.getName()).isEqualTo("Albert Einstein");
 			//create new inventor instance within add method of List
-			parser.parseExpression("Members2.add(new org.springframework.expression.spel.testresources.Inventor('Albert Einstein', 'German'))").getValue(societyContext);
+			parser.parseExpression("members.add(new org.springframework.expression.spel.testresources.Inventor('Albert Einstein', 'German'))").getValue(societyContext);
 		}
 	}
 
@@ -632,11 +627,25 @@ class CollectionSelection {
 		@Test
 		@SuppressWarnings("unchecked")
 		void selection() {
-			StandardEvaluationContext societyContext = new StandardEvaluationContext();
-			societyContext.setRootObject(new IEEE());
-			List<Inventor> list = (List<Inventor>) parser.parseExpression("Members2.?[nationality == 'Serbian']").getValue(societyContext);
-			assertThat(list).hasSize(1);
-			assertThat(list.get(0).getName()).isEqualTo("Nikola Tesla");
+			StandardEvaluationContext societyContext = new StandardEvaluationContext(new IEEE());
+			// evaluates to ["Nikola Tesla"]
+			List<Inventor> list = (List<Inventor>) parser.parseExpression("members.?[nationality == 'Serbian']")
+					.getValue(societyContext);
+			assertThat(list).map(Inventor::getName).containsOnly("Nikola Tesla");
+		}
+	}
+
+	@Nested
+	class CollectionProjection {
+
+		@Test
+		@SuppressWarnings("unchecked")
+		void projection() {
+			StandardEvaluationContext societyContext = new StandardEvaluationContext(new IEEE());
+			// evaluates to ["SmilJan", "Idvor"]
+			List placesOfBirth = parser.parseExpression("members.![placeOfBirth.city]")
+					.getValue(societyContext, List.class);
+			assertThat(placesOfBirth).containsExactly("SmilJan", "Idvor");
 		}
 	}
 
@@ -654,22 +663,20 @@ void templating() {
 
 
 	static class IEEE {
+
 		private String name;
 
-		public Inventor[] Members = new Inventor[1];
-		public List Members2 = new ArrayList();
-		public Map<String,Object> officers = new HashMap<>();
+		public List<Inventor> members = new ArrayList<>();
+
+		public Map<String,Object> officers = Map.of(
+				"president", pupin,
+				"advisors", List.of(tesla));
 
 		public List<Map<String, Object>> reverse = new ArrayList<>();
 
-		@SuppressWarnings("unchecked")
 		IEEE() {
-			officers.put("president",pupin);
-			List linv = new ArrayList();
-			linv.add(tesla);
-			officers.put("advisors",linv);
-			Members2.add(tesla);
-			Members2.add(pupin);
+			members.add(tesla);
+			members.add(pupin);
 
 			reverse.add(officers);
 		}
@@ -678,8 +685,13 @@ public boolean isMember(String name) {
 			return true;
 		}
 
-		public String getName() { return name; }
-		public void setName(String n) { this.name = n; }
+		public String getName() {
+			return this.name;
+		}
+
+		public void setName(String n) {
+			this.name = n;
+		}
 	}
 
 	static class StringUtils {