Add poc for EntityLookupConfiguration replacement.

Author: mp911de

src/main/java/org/springframework/data/core/MemberReference.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.core;
+
+import java.io.Serializable;
+import java.lang.reflect.Member;
+import java.util.function.Function;
+
+import org.springframework.util.Assert;
+
+/**
+ * PoC for REST EntityLookupConfiguration
+ *
+ * @author Mark Paluch
+ */
+public interface MemberReference<T, R> extends Function<T, R>, Serializable {
+
+	default Member getMember() {
+		return resolve(this);
+	}
+
+	public static Member resolve(Object object) {
+
+		Assert.notNull(object, "Object must not be null");
+		Assert.isInstanceOf(Serializable.class, object, "Object must be Serializable");
+
+		return new SamParser(MemberReference.class).parse(object.getClass().getClassLoader(), object).getMember();
+	}
+
+}

src/test/java/org/springframework/data/core/MemberReferenceTests.java

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+/*
+ * Copyright 2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.core;
+
+import static org.assertj.core.api.Assertions.*;
+
+import java.io.Serializable;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.core.convert.converter.Converter;
+
+/**
+ * @author Mark Paluch
+ */
+class MemberReferenceTests {
+
+	@Test
+	void shouldResolveMember() throws NoSuchMethodException {
+
+		MemberReference<Person, String> reference = Person::name;
+
+		assertThat(reference.getMember()).isEqualTo(Person.class.getMethod("name"));
+	}
+
+	@Test
+	void retrofitConverter() throws NoSuchMethodException {
+
+		Converter<Person, String> reference = convert(Person::name);
+
+		assertThat(MemberReference.resolve(reference)).isEqualTo(Person.class.getMethod("name"));
+	}
+
+	static <A, B, T extends Converter<A, B> & Serializable> T convert(T converter) {
+		return converter;
+	}
+
+	record Person(String name) {
+
+	}
+}