Consistent cache key implementation across transaction and cache attribute sources

Includes consistent applicability of class-level metadata to user-level methods only.

Issue: SPR-14017
Issue: SPR-14095

spring-core/src/main/java/org/springframework/core/MethodClassKey.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2002-2016 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.core;
+
+import java.lang.reflect.Method;
+
+import org.springframework.util.ObjectUtils;
+
+/**
+ * A common key class for a method against a specific target class,
+ * including {@link #toString()} representation and {@link Comparable}
+ * support (as suggested for custom {@code HashMap} keys as of Java 8).
+ *
+ * @author Juergen Hoeller
+ * @since 4.3
+ */
+public final class MethodClassKey implements Comparable<MethodClassKey> {
+
+	private final Method method;
+
+	private final Class<?> targetClass;
+
+
+	/**
+	 * Create a key object for the given method and target class.
+	 * @param method the method to wrap (must not be {@code null})
+	 * @param targetClass the target class that the method will be invoked
+	 * on (may be {@code null} if identical to the declaring class)
+	 */
+	public MethodClassKey(Method method, Class<?> targetClass) {
+		this.method = method;
+		this.targetClass = targetClass;
+	}
+
+
+	@Override
+	public boolean equals(Object other) {
+		if (this == other) {
+			return true;
+		}
+		if (!(other instanceof MethodClassKey)) {
+			return false;
+		}
+		MethodClassKey otherKey = (MethodClassKey) other;
+		return (this.method.equals(otherKey.method) &&
+				ObjectUtils.nullSafeEquals(this.targetClass, otherKey.targetClass));
+	}
+
+	@Override
+	public int hashCode() {
+		return this.method.hashCode() + (this.targetClass != null ? this.targetClass.hashCode() * 29 : 0);
+	}
+
+	@Override
+	public String toString() {
+		return this.method + (this.targetClass != null ? " on " + this.targetClass : "");
+	}
+
+	@Override
+	public int compareTo(MethodClassKey other) {
+		int result = this.method.getName().compareTo(other.method.getName());
+		if (result == 0) {
+			result = this.method.toString().compareTo(other.method.toString());
+			if (result == 0 && this.targetClass != null) {
+				result = this.targetClass.getName().compareTo(other.targetClass.getName());
+			}
+		}
+		return result;
+	}
+
+}