org.springframework.core.annotation.OrderUtils Maven / Gradle / Ivy
/*
* Copyright 2002-2019 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.core.annotation;
import java.lang.reflect.AnnotatedElement;
import java.util.Map;
import org.springframework.core.annotation.MergedAnnotations.SearchStrategy;
import org.springframework.lang.Nullable;
import org.springframework.util.ConcurrentReferenceHashMap;
/**
* General utility for determining the order of an object based on its type declaration.
* Handles Spring's {@link Order} annotation as well as {@link javax.annotation.Priority}.
*
* @author Stephane Nicoll
* @author Juergen Hoeller
* @since 4.1
* @see Order
* @see javax.annotation.Priority
*/
public abstract class OrderUtils {
/** Cache marker for a non-annotated Class. */
private static final Object NOT_ANNOTATED = new Object();
private static final String JAVAX_PRIORITY_ANNOTATION = "javax.annotation.Priority";
/** Cache for @Order value (or NOT_ANNOTATED marker) per Class. */
private static final Map orderCache = new ConcurrentReferenceHashMap<>(64);
/**
* Return the order on the specified {@code type}, or the specified
* default value if none can be found.
* Takes care of {@link Order @Order} and {@code @javax.annotation.Priority}.
* @param type the type to handle
* @return the priority value, or the specified default order if none can be found
* @since 5.0
* @see #getPriority(Class)
*/
public static int getOrder(Class type, int defaultOrder) {
Integer order = getOrder(type);
return (order != null ? order : defaultOrder);
}
/**
* Return the order on the specified {@code type}, or the specified
* default value if none can be found.
*
Takes care of {@link Order @Order} and {@code @javax.annotation.Priority}.
* @param type the type to handle
* @return the priority value, or the specified default order if none can be found
* @see #getPriority(Class)
*/
@Nullable
public static Integer getOrder(Class type, @Nullable Integer defaultOrder) {
Integer order = getOrder(type);
return (order != null ? order : defaultOrder);
}
/**
* Return the order on the specified {@code type}.
*
Takes care of {@link Order @Order} and {@code @javax.annotation.Priority}.
* @param type the type to handle
* @return the order value, or {@code null} if none can be found
* @see #getPriority(Class)
*/
@Nullable
public static Integer getOrder(Class type) {
return getOrderFromAnnotations(type, MergedAnnotations.from(type, SearchStrategy.TYPE_HIERARCHY));
}
/**
* Return the order from the specified annotations collection.
*
Takes care of {@link Order @Order} and
* {@code @javax.annotation.Priority}.
* @param element the source element
* @param annotations the annotation to consider
* @return the order value, or {@code null} if none can be found
*/
@Nullable
static Integer getOrderFromAnnotations(AnnotatedElement element, MergedAnnotations annotations) {
if (!(element instanceof Class)) {
return findOrder(annotations);
}
Object cached = orderCache.get(element);
if (cached != null) {
return (cached instanceof Integer ? (Integer) cached : null);
}
Integer result = findOrder(annotations);
orderCache.put(element, result != null ? result : NOT_ANNOTATED);
return result;
}
@Nullable
private static Integer findOrder(MergedAnnotations annotations) {
MergedAnnotation orderAnnotation = annotations.get(Order.class);
if (orderAnnotation.isPresent()) {
return orderAnnotation.getInt(MergedAnnotation.VALUE);
}
MergedAnnotation priorityAnnotation = annotations.get(JAVAX_PRIORITY_ANNOTATION);
if (priorityAnnotation.isPresent()) {
return priorityAnnotation.getInt(MergedAnnotation.VALUE);
}
return null;
}
/**
* Return the value of the {@code javax.annotation.Priority} annotation
* declared on the specified type, or {@code null} if none.
* @param type the type to handle
* @return the priority value if the annotation is declared, or {@code null} if none
*/
@Nullable
public static Integer getPriority(Class type) {
return MergedAnnotations.from(type, SearchStrategy.TYPE_HIERARCHY).get(JAVAX_PRIORITY_ANNOTATION)
.getValue(MergedAnnotation.VALUE, Integer.class).orElse(null);
}
}