Polishing.

Apply consistent formatting. Extract superinterface for rendering. Refine tests.

See #3961
Original pull request: #3962

Author: mp911de

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/JpqlQueryBuilder.java

@@ -142,6 +142,7 @@ public Select select(Selection selection) {
 			Selection postProcess(Selection selection) {
 				return distinct ? new DistinctSelection(selection) : selection;
 			}
+
 		};
 	}
 
@@ -299,6 +300,7 @@ public static WhereStep where(Origin source, PropertyPath path) {
 	public static WhereStep where(Expression rhs) {
 
 		return new WhereStep() {
+
 			@Override
 			public Predicate between(Expression lower, Expression upper) {
 				return new BetweenPredicate(rhs, lower, upper);
@@ -393,6 +395,7 @@ public Predicate eq(Expression value) {
 			public Predicate neq(Expression value) {
 				return new OperatorPredicate(rhs, "!=", value);
 			}
+
 		};
 	}
 
@@ -506,7 +509,9 @@ default Select select(JpqlQueryBuilder.PathExpression path) {
 	}
 
 	public interface Selection {
+
 		String render(RenderContext context);
+
 	}
 
 	/**
@@ -525,6 +530,7 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	static PathAndOrigin path(Origin origin, String path) {
@@ -538,29 +544,28 @@ static PathAndOrigin path(Origin origin, String path) {
 				throw new RuntimeException(e);
 			}
 		}
+
 		if (origin instanceof Join join) {
 
 			Origin parent = join.source;
 			List<String> segments = new ArrayList<>();
 			segments.add(join.path);
 			while (!(parent instanceof Entity)) {
-				if (parent instanceof Join pj) {
-					parent = pj.source;
-					segments.add(pj.path);
+				if (parent instanceof Join parentJoin) {
+					parent = parentJoin.source;
+					segments.add(parentJoin.path);
 				} else {
 					parent = null;
 				}
 			}
 
-			if (parent instanceof Entity) {
-				Collections.reverse(segments);
-				segments.add(path);
-				PathAndOrigin path1 = path(parent, StringUtils.collectionToDelimitedString(segments, "."));
-				return new PathAndOrigin(path1.path().getLeafProperty(), origin, false);
-			}
+			Collections.reverse(segments);
+			segments.add(path);
+			PathAndOrigin joinedPath = path(parent, StringUtils.collectionToDelimitedString(segments, "."));
+			return new PathAndOrigin(joinedPath.path().getLeafProperty(), origin, false);
 		}
-		throw new IllegalStateException(" oh no ");
 
+		throw new IllegalStateException("🙈 Unsupported origin type: " + origin);
 	}
 
 	/**
@@ -579,6 +584,7 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	/**
@@ -598,6 +604,7 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	/**
@@ -618,6 +625,7 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	/**
@@ -652,21 +660,29 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	/**
-	 * {@code WHERE} predicate.
+	 * Interface specifying a predicate or expression that can be rendered to {@code String}.
 	 */
-	public interface Predicate {
+	public interface Renderable {
 
 		/**
-		 * Render the predicate given {@link RenderContext}.
+		 * Render the predicate or expression given {@link RenderContext}.
 		 *
 		 * @param context
 		 * @return
 		 */
 		String render(RenderContext context);
 
+	}
+
+	/**
+	 * {@code WHERE} predicate.
+	 */
+	public interface Predicate extends Renderable {
+
 		/**
 		 * {@code OR}-concatenate this predicate with {@code other}.
 		 *
@@ -701,21 +717,21 @@ default Predicate and(Predicate other) { // don't like the structuring of this a
 		default Predicate nest() {
 			return new NestedPredicate(this);
 		}
+
 	}
 
 	/**
 	 * Interface specifying an expression that can be rendered to {@code String}.
 	 */
-	public interface Expression {
+	public interface Expression extends Renderable {
 
 		/**
-		 * Render the expression given {@link RenderContext}.
+		 * Create an {@link AliasedExpression} with the given {@code alias}. If the expression is already aliased, the
+		 * previous alias is discarded and replaced with the new one.
 		 *
-		 * @param context
+		 * @param alias
 		 * @return
 		 */
-		String render(RenderContext context);
-
 		default AliasedExpression as(String alias) {
 
 			if (this instanceof DefaultAliasedExpression de) {
@@ -724,6 +740,7 @@ default AliasedExpression as(String alias) {
 
 			return new DefaultAliasedExpression(this, alias);
 		}
+
 	}
 
 	/**
@@ -756,6 +773,7 @@ public String getAlias() {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	/**
@@ -768,6 +786,7 @@ public interface PathExpression extends Expression {
 		 * @return the associated {@link PropertyPath}.
 		 */
 		PropertyPath getPropertyPath();
+
 	}
 
 	/**
@@ -865,6 +884,7 @@ String render() {
 
 			return result.toString();
 		}
+
 	}
 
 	/**
@@ -889,6 +909,7 @@ public AbstractJpqlQuery where(Predicate predicate) {
 		public String toString() {
 			return render();
 		}
+
 	}
 
 	record OrderExpression(Expression sortExpression, @org.springframework.lang.Nullable Sort.Direction direction,
@@ -915,6 +936,7 @@ public String render(RenderContext context) {
 
 			return builder.toString();
 		}
+
 	}
 
 	/**
@@ -966,6 +988,7 @@ public String prefixWithAlias(Origin source, String fragment) {
 		public boolean isConstructorContext() {
 			return false;
 		}
+
 	}
 
 	static class ConstructorContext extends RenderContext {
@@ -978,6 +1001,7 @@ static class ConstructorContext extends RenderContext {
 		public boolean isConstructorContext() {
 			return true;
 		}
+
 	}
 
 	/**
@@ -992,6 +1016,7 @@ public interface Origin {
 		 * @return the simple name of the origin (e.g. {@link Class#getSimpleName()})
 		 */
 		String getName();
+
 	}
 
 	/**
@@ -1001,6 +1026,7 @@ public interface Origin {
 	public interface Bindable {
 
 		boolean isRoot();
+
 	}
 
 	/**
@@ -1283,6 +1309,7 @@ default Predicate like(String value, String escape) {
 		 * @return
 		 */
 		Predicate neq(Expression value);
+
 	}
 
 	record LiteralExpression(String expression) implements Expression {
@@ -1296,6 +1323,7 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	record StringLiteralExpression(String literal) implements Expression {
@@ -1313,6 +1341,7 @@ public String raw() {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	record ParameterExpression(ParameterPlaceholder parameter) implements Expression {
@@ -1326,6 +1355,7 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	record FunctionExpression(String function, List<Expression> arguments) implements Expression {
@@ -1351,6 +1381,7 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	record OperatorPredicate(Expression path, String operator, Expression predicate) implements Predicate {
@@ -1364,6 +1395,7 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	record MemberOfPredicate(Expression path, String operator, Expression predicate) implements Predicate {
@@ -1377,6 +1409,7 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	record LhsPredicate(Expression path, String predicate) implements Predicate {
@@ -1390,6 +1423,7 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	record BetweenPredicate(Expression path, Expression lower, Expression upper) implements Predicate {
@@ -1403,6 +1437,7 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	record LikePredicate(Expression left, String operator, Expression right, String escape) implements Predicate {
@@ -1416,27 +1451,29 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	record InPredicate(Expression path, String operator, Expression predicate) implements Predicate {
 
 		@Override
 		public String render(RenderContext context) {
 
-			String predicateStr = predicate.render(context);
-			
-			// Avoid double parentheses if predicate string already starts and ends with parentheses
-			if (predicateStr.startsWith("(") && predicateStr.endsWith(")")) {
-				return "%s %s %s".formatted(path.render(context), operator, predicateStr);
-			}
-			
-			return "%s %s (%s)".formatted(path.render(context), operator, predicateStr);
+			Expression predicate = this.predicate;
+			String rendered = predicate.render(context);
+
+			return (hasParenthesis(rendered) ? "%s %s %s" : "%s %s (%s)").formatted(path.render(context), operator, rendered);
 		}
 
 		@Override
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
+		private static boolean hasParenthesis(String str) {
+			return str.startsWith("(") && str.endsWith(")");
+		}
+
 	}
 
 	record AndPredicate(Predicate left, Predicate right) implements Predicate {
@@ -1450,6 +1487,7 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	record OrPredicate(Predicate left, Predicate right) implements Predicate {
@@ -1463,6 +1501,7 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	record NestedPredicate(Predicate delegate) implements Predicate {
@@ -1476,6 +1515,7 @@ public String render(RenderContext context) {
 		public String toString() {
 			return render(RenderContext.EMPTY);
 		}
+
 	}
 
 	/**
@@ -1507,6 +1547,7 @@ public String render(RenderContext context) {
 		public String getAlias() {
 			return path().getSegment();
 		}
+
 	}
 
 	/**
@@ -1541,5 +1582,7 @@ public static ParameterPlaceholder named(String name) {
 			Assert.hasText(name, "Placeholder name must not be empty");
 			return new ParameterPlaceholder(":%s".formatted(name));
 		}
+
 	}
+
 }