DAATCMNS-1449 - Added API to record method invocations.

Introduced MethodInvocationRecorder to record method invocations on types to obtain the property traversal those invocations represent.

Recorded<ZipCode> recorded = MethodInvocationRecorder.forProxyOf(Person.class)
  .record(Person::getAddress)
  .record(Address::getZipCode);

assertThat(recorded.getPropertyPath)).hasValue("address.zipCode");

src/test/java/org/springframework/data/util/MethodInvocationRecorderUnitTests.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2016-2018 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
+ *
+ *      http://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.util;
+
+import static org.assertj.core.api.Assertions.*;
+
+import lombok.Getter;
+
+import java.util.Collection;
+
+import org.junit.Test;
+import org.springframework.data.util.MethodInvocationRecorder.Recorded;
+
+/**
+ * Unit tests for {@link MethodInvocationRecorder}.
+ *
+ * @author Oliver Gierke
+ * @soundtrack The Intersphere - Don't Think Twice (The Grand Delusion)
+ */
+public class MethodInvocationRecorderUnitTests {
+
+	Recorded<Foo> recorder = MethodInvocationRecorder.forProxyOf(Foo.class);
+
+	@Test // DATACMNS-1449
+	public void createsPropertyPathForSimpleMethodReference() {
+
+		Recorded<Bar> wrapper = recorder.record(Foo::getBar);
+
+		assertThat(wrapper.getPropertyPath()).hasValue("bar");
+	}
+
+	@Test // DATACMNS-1449
+	public void createsPropertyPathForNestedMethodReference() {
+
+		Recorded<FooBar> wrapper = recorder.record(Foo::getBar).record(Bar::getFooBar);
+
+		assertThat(wrapper.getPropertyPath()).hasValue("bar.fooBar");
+	}
+
+	@Test // DATACMNS-1449
+	public void createsPropertyPathForNestedCall() {
+
+		Recorded<FooBar> wrapper = recorder.record((Foo source) -> source.getBar().getFooBar());
+
+		assertThat(wrapper.getPropertyPath()).hasValue("bar.fooBar");
+	}
+
+	@Test // DATACMNS-1449
+	public void usesCustomPropertyNamingStrategy() {
+
+		Recorded<Bar> recorded = MethodInvocationRecorder.forProxyOf(Foo.class).record(Foo::getBar);
+
+		assertThat(recorded.getPropertyPath(method -> method.getName())).hasValue("getBar");
+	}
+
+	@Test // DATACMNS-1449
+	public void registersLookupToFinalType() {
+		assertThat(recorder.record(Foo::getName).getPropertyPath()).hasValue("name");
+	}
+
+	@Test
+	public void recordsInvocationOnInterface() {
+
+		Recorded<Sample> recorder = MethodInvocationRecorder.forProxyOf(Sample.class);
+
+		assertThat(recorder.record(Sample::getName).getPropertyPath()).hasValue("name");
+	}
+
+	@Getter
+	static class Foo {
+		Bar bar;
+		Collection<Bar> bars;
+		String name;
+	}
+
+	@Getter
+	static class Bar {
+		FooBar fooBar;
+	}
+
+	static class FooBar {}
+
+	interface Sample {
+		String getName();
+	}
+}