Avoid instantiating ComparableComparator via reflection.

We now use a dedicated instance instead of relying upon reflectively created ones, however we still need to register the compare call for reflective access.

Resolves: #564

Author: christophstrobl

Diff for: src/main/java/org/springframework/data/keyvalue/aot/KeyValueRuntimeHints.java

@@ -16,7 +16,9 @@
 package org.springframework.data.keyvalue.aot;
 
 import java.util.Arrays;
+import java.util.List;
 
+import org.springframework.aot.hint.ExecutableMode;
 import org.springframework.aot.hint.MemberCategory;
 import org.springframework.aot.hint.RuntimeHints;
 import org.springframework.aot.hint.RuntimeHintsRegistrar;
@@ -41,5 +43,9 @@ public void registerHints(RuntimeHints hints, @Nullable ClassLoader classLoader)
 						TypeReference.of(org.springframework.data.keyvalue.repository.support.SimpleKeyValueRepository.class),
 						TypeReference.of(KeyValuePartTreeQuery.class)),
 				hint -> hint.withMembers(MemberCategory.INVOKE_DECLARED_CONSTRUCTORS, MemberCategory.INVOKE_DECLARED_METHODS));
+
+		hints.reflection().registerType(org.springframework.util.comparator.NullSafeComparator.class,
+				builder -> builder.withMethod("compare",
+						List.of(TypeReference.of(Object.class), TypeReference.of(Object.class)), ExecutableMode.INVOKE));
 	}
 }

Diff for: src/main/java/org/springframework/data/keyvalue/core/SpelPropertyComparator.java

@@ -19,8 +19,10 @@
 
 import org.springframework.expression.spel.standard.SpelExpression;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
+import org.springframework.expression.spel.support.SimpleEvaluationContext;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.comparator.NullSafeComparator;
 
 /**
  * {@link Comparator} implementation using {@link SpelExpression}.
@@ -115,9 +117,8 @@ protected SpelExpression getExpression() {
 	 */
 	protected String buildExpressionForPath() {
 
-		String rawExpression = String.format(
-				"new org.springframework.util.comparator.NullSafeComparator(new org.springframework.util.comparator.ComparableComparator(), %s).compare(#arg1?.%s,#arg2?.%s)",
-				Boolean.toString(this.nullsFirst), path.replace(".", "?."), path.replace(".", "?."));
+		String rawExpression = String.format("#comparator.compare(#arg1?.%s,#arg2?.%s)", path.replace(".", "?."),
+				path.replace(".", "?."));
 
 		return rawExpression;
 	}
@@ -127,8 +128,12 @@ public int compare(T arg1, T arg2) {
 
 		SpelExpression expressionToUse = getExpression();
 
-		expressionToUse.getEvaluationContext().setVariable("arg1", arg1);
-		expressionToUse.getEvaluationContext().setVariable("arg2", arg2);
+		SimpleEvaluationContext ctx = SimpleEvaluationContext.forReadOnlyDataBinding().withInstanceMethods().build();
+		ctx.setVariable("comparator", new NullSafeComparator(Comparator.naturalOrder(), this.nullsFirst));
+		ctx.setVariable("arg1", arg1);
+		ctx.setVariable("arg2", arg2);
+
+		expressionToUse.setEvaluationContext(ctx);
 
 		return expressionToUse.getValue(Integer.class) * (asc ? 1 : -1);
 	}