crabapples
/
Sentinel
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Add @SpiOrder annotation and update SPI loader for loading SPI with highest precedence 

Signed-off-by: Eric Zhao <sczyh16@gmail.com>
This commit is contained in:
Eric Zhao 2019-04-17 14:23:48 +08:00
parent df27e3ef9d
commit 79211f055c
2 changed files with 182 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
sentinel-core/src/main/java/com/alibaba/csp/sentinel/spi/SpiOrder.java Normal file
View File

@ -0,0 +1,48 @@
/*
* Copyright 1999-2019 Alibaba Group Holding Ltd.
*
* 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 com.alibaba.csp.sentinel.spi;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* @author Eric Zhao
* @since 1.6.0
*/
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE})
@Documented
public @interface SpiOrder {
/**
* Represents the lowest precedence.
*/
int LOWEST_PRECEDENCE = Integer.MAX_VALUE;
/**
* Represents the highest precedence.
*/
int HIGHEST_PRECEDENCE = Integer.MIN_VALUE;
/**
* The SPI precedence value. Lowest precedence by default.
*
* @return the precedence value
*/
int value() default LOWEST_PRECEDENCE;
}

145
sentinel-core/src/main/java/com/alibaba/csp/sentinel/util/SpiLoader.java
View File

@ -15,11 +15,16 @@
*/
package com.alibaba.csp.sentinel.util;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.ServiceLoader;
import java.util.concurrent.ConcurrentHashMap;
import com.alibaba.csp.sentinel.log.RecordLog;
import com.alibaba.csp.sentinel.spi.SpiOrder;
/**
* @author Eric Zhao
* @since 1.4.0
@ -29,19 +34,137 @@ public final class SpiLoader {
private static final Map<String, ServiceLoader> SERVICE_LOADER_MAP = new ConcurrentHashMap<String, ServiceLoader>();
public static <T> T loadFirstInstance(Class<T> clazz) {
String key = clazz.getName();
// Not thread-safe, as it's expected to be resolved in a thread-safe context.
ServiceLoader<T> serviceLoader = SERVICE_LOADER_MAP.get(key);
if (serviceLoader == null) {
serviceLoader = ServiceLoader.load(clazz);
SERVICE_LOADER_MAP.put(key, serviceLoader);
try {
String key = clazz.getName();
// Not thread-safe, as it's expected to be resolved in a thread-safe context.
ServiceLoader<T> serviceLoader = SERVICE_LOADER_MAP.get(key);
if (serviceLoader == null) {
serviceLoader = ServiceLoader.load(clazz);
SERVICE_LOADER_MAP.put(key, serviceLoader);
}
Iterator<T> iterator = serviceLoader.iterator();
if (iterator.hasNext()) {
return iterator.next();
} else {
return null;
}
} catch (Throwable t) {
RecordLog.warn("[SpiLoader] ERROR: loadFirstInstance failed", t);
t.printStackTrace();
return null;
}
}
/**
* Load the SPI instance with highest priority.
*
* @param clazz class of the SPI
* @param <T> SPI type
* @return the SPI instance with highest priority if exists, or else false
* @since 1.6.0
*/
public static <T> T loadHighestPriorityInstance(Class<T> clazz) {
try {
String key = clazz.getName();
// Not thread-safe, as it's expected to be resolved in a thread-safe context.
ServiceLoader<T> serviceLoader = SERVICE_LOADER_MAP.get(key);
if (serviceLoader == null) {
serviceLoader = ServiceLoader.load(clazz);
SERVICE_LOADER_MAP.put(key, serviceLoader);
}
SpiOrderWrapper<T> w = null;
for (T spi : serviceLoader) {
int order = SpiOrderResolver.resolveOrder(spi);
RecordLog.info("[SpiLoader] Found {0} SPI: {1} with order " + order, clazz.getSimpleName(),
spi.getClass().getCanonicalName());
if (w == null || order < w.order) {
w = new SpiOrderWrapper<>(order, spi);
}
}
return w == null ? null : w.spi;
} catch (Throwable t) {
RecordLog.warn("[SpiLoader] ERROR: loadHighestPriorityInstance failed", t);
t.printStackTrace();
return null;
}
}
/**
* Load and sorted SPI instance list.
*
* @param clazz class of the SPI
* @param <T> SPI type
* @return sorted SPI instance list
* @since 1.6.0
*/
public static <T> List<T> loadInstanceListSorted(Class<T> clazz) {
try {
String key = clazz.getName();
// Not thread-safe, as it's expected to be resolved in a thread-safe context.
ServiceLoader<T> serviceLoader = SERVICE_LOADER_MAP.get(key);
if (serviceLoader == null) {
serviceLoader = ServiceLoader.load(clazz);
SERVICE_LOADER_MAP.put(key, serviceLoader);
}
List<SpiOrderWrapper<T>> orderWrappers = new ArrayList<>();
for (T spi : serviceLoader) {
int order = SpiOrderResolver.resolveOrder(spi);
// Since SPI is lazy initialized in ServiceLoader, we use online sort algorithm here.
SpiOrderResolver.insertSorted(orderWrappers, spi, order);
RecordLog.info("[SpiLoader] Found {0} SPI: {1} with order " + order, clazz.getSimpleName(),
spi.getClass().getCanonicalName());
}
List<T> list = new ArrayList<>();
for (int i = 0; i < orderWrappers.size(); i++) {
list.add(i, orderWrappers.get(i).spi);
}
return list;
} catch (Throwable t) {
RecordLog.warn("[SpiLoader] ERROR: loadInstanceListSorted failed", t);
t.printStackTrace();
return new ArrayList<>();
}
}
private static class SpiOrderResolver {
private static <T> void insertSorted(List<SpiOrderWrapper<T>> list, T spi, int order) {
int idx = 0;
for (; idx < list.size(); idx++) {
if (list.get(idx).getOrder() > order) {
break;
}
}
list.add(idx, new SpiOrderWrapper<>(order, spi));
}
Iterator<T> iterator = serviceLoader.iterator();
if (iterator.hasNext()) {
return iterator.next();
} else {
return null;
private static <T> int resolveOrder(T spi) {
if (!spi.getClass().isAnnotationPresent(SpiOrder.class)) {
// Lowest precedence by default.
return SpiOrder.LOWEST_PRECEDENCE;
} else {
return spi.getClass().getAnnotation(SpiOrder.class).value();
}
}
}
private static class SpiOrderWrapper<T> {
private final int order;
private final T spi;
SpiOrderWrapper(int order, T spi) {
this.order = order;
this.spi = spi;
}
int getOrder() {
return order;
}
T getSpi() {
return spi;
}
}