dubbo ExtensionLoader 源码
dubbo ExtensionLoader 代码
文件路径：/dubbo-common/src/main/java/org/apache/dubbo/common/extension/ExtensionLoader.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.dubbo.common.extension;
import org.apache.dubbo.common.Extension;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.beans.support.InstantiationStrategy;
import org.apache.dubbo.common.context.Lifecycle;
import org.apache.dubbo.common.extension.support.ActivateComparator;
import org.apache.dubbo.common.extension.support.WrapperComparator;
import org.apache.dubbo.common.lang.Prioritized;
import org.apache.dubbo.common.logger.Logger;
import org.apache.dubbo.common.logger.LoggerFactory;
import org.apache.dubbo.common.resource.Disposable;
import org.apache.dubbo.common.utils.ArrayUtils;
import org.apache.dubbo.common.utils.ClassLoaderResourceLoader;
import org.apache.dubbo.common.utils.ClassUtils;
import org.apache.dubbo.common.utils.CollectionUtils;
import org.apache.dubbo.common.utils.ConcurrentHashSet;
import org.apache.dubbo.common.utils.ConfigUtils;
import org.apache.dubbo.common.utils.Holder;
import org.apache.dubbo.common.utils.NativeUtils;
import org.apache.dubbo.common.utils.ReflectUtils;
import org.apache.dubbo.common.utils.StringUtils;
import org.apache.dubbo.rpc.model.ApplicationModel;
import org.apache.dubbo.rpc.model.FrameworkModel;
import org.apache.dubbo.rpc.model.ModuleModel;
import org.apache.dubbo.rpc.model.ScopeModel;
import org.apache.dubbo.rpc.model.ScopeModelAccessor;
import org.apache.dubbo.rpc.model.ScopeModelAware;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.lang.ref.SoftReference;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Properties;
import java.util.ServiceLoader;
import java.util.Set;
import java.util.TreeMap;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.regex.Pattern;
import static java.util.Arrays.asList;
import static java.util.ServiceLoader.load;
import static java.util.stream.StreamSupport.stream;
import static org.apache.dubbo.common.constants.CommonConstants.COMMA_SPLIT_PATTERN;
import static org.apache.dubbo.common.constants.CommonConstants.DEFAULT_KEY;
import static org.apache.dubbo.common.constants.CommonConstants.REMOVE_VALUE_PREFIX;
/**
* {@link org.apache.dubbo.rpc.model.ApplicationModel}, {@code DubboBootstrap} and this class are
* at present designed to be singleton or static (by itself totally static or uses some static fields).
* So the instances returned from them are of process or classloader scope. If you want to support
* multiple dubbo servers in a single process, you may need to refactor these three classes.
* <p>
* Load dubbo extensions
* <ul>
* <li>auto inject dependency extension </li>
* <li>auto wrap extension in wrapper </li>
* <li>default extension is an adaptive instance</li>
* </ul>
*
* @see <a href="http://java.sun.com/j2se/1.5.0/docs/guide/jar/jar.html#Service%20Provider">Service Provider in Java 5</a>
* @see org.apache.dubbo.common.extension.SPI
* @see org.apache.dubbo.common.extension.Adaptive
* @see org.apache.dubbo.common.extension.Activate
*/
public class ExtensionLoader<T> {
private static final Logger logger = LoggerFactory.getLogger(ExtensionLoader.class);
private static final Pattern NAME_SEPARATOR = Pattern.compile("\\s*[,]+\\s*");
private static final String SPECIAL_SPI_PROPERTIES = "special_spi.properties";
private final ConcurrentMap<Class<?>, Object> extensionInstances = new ConcurrentHashMap<>(64);
private final Class<?> type;
private final ExtensionInjector injector;
private final ConcurrentMap<Class<?>, String> cachedNames = new ConcurrentHashMap<>();
private final Holder<Map<String, Class<?>>> cachedClasses = new Holder<>();
private final Map<String, Object> cachedActivates = Collections.synchronizedMap(new LinkedHashMap<>());
private final Map<String, Set<String>> cachedActivateGroups = Collections.synchronizedMap(new LinkedHashMap<>());
private final Map<String, String[][]> cachedActivateValues = Collections.synchronizedMap(new LinkedHashMap<>());
private final ConcurrentMap<String, Holder<Object>> cachedInstances = new ConcurrentHashMap<>();
private final Holder<Object> cachedAdaptiveInstance = new Holder<>();
private volatile Class<?> cachedAdaptiveClass = null;
private String cachedDefaultName;
private volatile Throwable createAdaptiveInstanceError;
private Set<Class<?>> cachedWrapperClasses;
private Map<String, IllegalStateException> exceptions = new ConcurrentHashMap<>();
private static volatile LoadingStrategy[] strategies = loadLoadingStrategies();
private static Map<String,String> specialSPILoadingStrategyMap = getSpecialSPILoadingStrategyMap();
private static SoftReference<Map<java.net.URL,List<String>>> urlListMapCache = new SoftReference<>(new ConcurrentHashMap<>());
private static List<String> ignoredInjectMethodsDesc = getIgnoredInjectMethodsDesc();
/**
* Record all unacceptable exceptions when using SPI
*/
private Set<String> unacceptableExceptions = new ConcurrentHashSet<>();
private ExtensionDirector extensionDirector;
private List<ExtensionPostProcessor> extensionPostProcessors;
private InstantiationStrategy instantiationStrategy;
private ActivateComparator activateComparator;
private ScopeModel scopeModel;
private AtomicBoolean destroyed = new AtomicBoolean();
public static void setLoadingStrategies(LoadingStrategy... strategies) {
if (ArrayUtils.isNotEmpty(strategies)) {
ExtensionLoader.strategies = strategies;
}
}
/**
* Load all {@link Prioritized prioritized} {@link LoadingStrategy Loading Strategies} via {@link ServiceLoader}
*
* @return non-null
* @since 2.7.7
*/
private static LoadingStrategy[] loadLoadingStrategies() {
return stream(load(LoadingStrategy.class).spliterator(), false)
.sorted()
.toArray(LoadingStrategy[]::new);
}
/**
* some spi are implements by dubbo framework only and scan multi classloaders resources may cause
* application startup very slow
* @return
*/
private static Map<String, String> getSpecialSPILoadingStrategyMap() {
Map map = new ConcurrentHashMap<>();
Properties properties = loadProperties(ExtensionLoader.class.getClassLoader(), SPECIAL_SPI_PROPERTIES);
map.putAll(properties);
return map;
}
/**
* Get all {@link LoadingStrategy Loading Strategies}
*
* @return non-null
* @see LoadingStrategy
* @see Prioritized
* @since 2.7.7
*/
public static List<LoadingStrategy> getLoadingStrategies() {
return asList(strategies);
}
private static List<String> getIgnoredInjectMethodsDesc() {
List<String> ignoreInjectMethodsDesc = new ArrayList<>();
Arrays.stream(ScopeModelAware.class.getMethods()).map(ReflectUtils::getDesc).forEach(ignoreInjectMethodsDesc::add);
Arrays.stream(ExtensionAccessorAware.class.getMethods()).map(ReflectUtils::getDesc).forEach(ignoreInjectMethodsDesc::add);
return ignoreInjectMethodsDesc;
}
ExtensionLoader(Class<?> type, ExtensionDirector extensionDirector, ScopeModel scopeModel) {
this.type = type;
this.extensionDirector = extensionDirector;
this.extensionPostProcessors = extensionDirector.getExtensionPostProcessors();
initInstantiationStrategy();
this.injector = (type == ExtensionInjector.class ? null : extensionDirector.getExtensionLoader(ExtensionInjector.class)
.getAdaptiveExtension());
this.activateComparator = new ActivateComparator(extensionDirector);
this.scopeModel = scopeModel;
}
private void initInstantiationStrategy() {
instantiationStrategy = extensionPostProcessors.stream()
.filter(extensionPostProcessor -> extensionPostProcessor instanceof ScopeModelAccessor)
.map(extensionPostProcessor -> new InstantiationStrategy((ScopeModelAccessor) extensionPostProcessor))
.findFirst()
.orElse(new InstantiationStrategy());
}
/**
* @see ApplicationModel#getExtensionDirector()
* @see FrameworkModel#getExtensionDirector()
* @see ModuleModel#getExtensionDirector()
* @see ExtensionDirector#getExtensionLoader(java.lang.Class)
* @deprecated get extension loader from extension director of some module.
*/
@Deprecated
public static <T> ExtensionLoader<T> getExtensionLoader(Class<T> type) {
return ApplicationModel.defaultModel().getDefaultModule().getExtensionLoader(type);
}
@Deprecated
public static void resetExtensionLoader(Class type) {
}
public void destroy() {
if (!destroyed.compareAndSet(false, true)) {
return;
}
// destroy raw extension instance
extensionInstances.forEach((type, instance) -> {
if (instance instanceof Disposable) {
Disposable disposable = (Disposable) instance;
try {
disposable.destroy();
} catch (Exception e) {
logger.error("Error destroying extension " + disposable, e);
}
}
});
extensionInstances.clear();
// destroy wrapped extension instance
for (Holder<Object> holder : cachedInstances.values()) {
Object wrappedInstance = holder.get();
if (wrappedInstance instanceof Disposable) {
Disposable disposable = (Disposable) wrappedInstance;
try {
disposable.destroy();
} catch (Exception e) {
logger.error("Error destroying extension " + disposable, e);
}
}
}
cachedInstances.clear();
}
private void checkDestroyed() {
if (destroyed.get()) {
throw new IllegalStateException("ExtensionLoader is destroyed: " + type);
}
}
public String getExtensionName(T extensionInstance) {
return getExtensionName(extensionInstance.getClass());
}
public String getExtensionName(Class<?> extensionClass) {
getExtensionClasses();// load class
return cachedNames.get(extensionClass);
}
/**
* This is equivalent to {@code getActivateExtension(url, key, null)}
*
* @param url url
* @param key url parameter key which used to get extension point names
* @return extension list which are activated.
* @see #getActivateExtension(org.apache.dubbo.common.URL, String, String)
*/
public List<T> getActivateExtension(URL url, String key) {
return getActivateExtension(url, key, null);
}
/**
* This is equivalent to {@code getActivateExtension(url, values, null)}
*
* @param url url
* @param values extension point names
* @return extension list which are activated
* @see #getActivateExtension(org.apache.dubbo.common.URL, String[], String)
*/
public List<T> getActivateExtension(URL url, String[] values) {
return getActivateExtension(url, values, null);
}
/**
* This is equivalent to {@code getActivateExtension(url, url.getParameter(key).split(","), null)}
*
* @param url url
* @param key url parameter key which used to get extension point names
* @param group group
* @return extension list which are activated.
* @see #getActivateExtension(org.apache.dubbo.common.URL, String[], String)
*/
public List<T> getActivateExtension(URL url, String key, String group) {
String value = url.getParameter(key);
return getActivateExtension(url, StringUtils.isEmpty(value) ? null : COMMA_SPLIT_PATTERN.split(value), group);
}
/**
* Get activate extensions.
*
* @param url url
* @param values extension point names
* @param group group
* @return extension list which are activated
* @see org.apache.dubbo.common.extension.Activate
*/
@SuppressWarnings("deprecation")
public List<T> getActivateExtension(URL url, String[] values, String group) {
checkDestroyed();
// solve the bug of using @SPI's wrapper method to report a null pointer exception.
Map<Class<?>, T> activateExtensionsMap = new TreeMap<>(activateComparator);
List<String> names = values == null ? new ArrayList<>(0) : asList(values);
Set<String> namesSet = new HashSet<>(names);
if (!namesSet.contains(REMOVE_VALUE_PREFIX + DEFAULT_KEY)) {
if (cachedActivateGroups.size() == 0) {
synchronized (cachedActivateGroups) {
// cache all extensions
if (cachedActivateGroups.size() == 0) {
getExtensionClasses();
for (Map.Entry<String, Object> entry : cachedActivates.entrySet()) {
String name = entry.getKey();
Object activate = entry.getValue();
String[] activateGroup, activateValue;
if (activate instanceof Activate) {
activateGroup = ((Activate) activate).group();
activateValue = ((Activate) activate).value();
} else if (activate instanceof com.alibaba.dubbo.common.extension.Activate) {
activateGroup = ((com.alibaba.dubbo.common.extension.Activate) activate).group();
activateValue = ((com.alibaba.dubbo.common.extension.Activate) activate).value();
} else {
continue;
}
cachedActivateGroups.put(name, new HashSet<>(Arrays.asList(activateGroup)));
String[][] keyPairs = new String[activateValue.length][];
for (int i = 0; i < activateValue.length; i++) {
if (activateValue[i].contains(":")) {
keyPairs[i] = new String[2];
String[] arr = activateValue[i].split(":");
keyPairs[i][0] = arr[0];
keyPairs[i][1] = arr[1];
} else {
keyPairs[i] = new String[1];
keyPairs[i][0] = activateValue[i];
}
}
cachedActivateValues.put(name, keyPairs);
}
}
}
}
// traverse all cached extensions
cachedActivateGroups.forEach((name, activateGroup) -> {
if (isMatchGroup(group, activateGroup)
&& !namesSet.contains(name)
&& !namesSet.contains(REMOVE_VALUE_PREFIX + name)
&& isActive(cachedActivateValues.get(name), url)) {
activateExtensionsMap.put(getExtensionClass(name), getExtension(name));
}
});
}
if (namesSet.contains(DEFAULT_KEY)) {
// will affect order
// `ext1,default,ext2` means ext1 will happens before all of the default extensions while ext2 will after them
ArrayList<T> extensionsResult = new ArrayList<>(activateExtensionsMap.size() + names.size());
for (String name : names) {
if (name.startsWith(REMOVE_VALUE_PREFIX)
|| namesSet.contains(REMOVE_VALUE_PREFIX + name)) {
continue;
}
if (DEFAULT_KEY.equals(name)) {
extensionsResult.addAll(activateExtensionsMap.values());
continue;
}
if (containsExtension(name)) {
extensionsResult.add(getExtension(name));
}
}
return extensionsResult;
} else {
// add extensions, will be sorted by its order
for (String name : names) {
if (name.startsWith(REMOVE_VALUE_PREFIX)
|| namesSet.contains(REMOVE_VALUE_PREFIX + name)) {
continue;
}
if (DEFAULT_KEY.equals(name)) {
continue;
}
if (containsExtension(name)) {
activateExtensionsMap.put(getExtensionClass(name), getExtension(name));
}
}
return new ArrayList<>(activateExtensionsMap.values());
}
}
public List<T> getActivateExtensions() {
checkDestroyed();
List<T> activateExtensions = new ArrayList<>();
TreeMap<Class<?>, T> activateExtensionsMap = new TreeMap<>(activateComparator);
getExtensionClasses();
for (Map.Entry<String, Object> entry : cachedActivates.entrySet()) {
String name = entry.getKey();
Object activate = entry.getValue();
if (!(activate instanceof Activate)) {
continue;
}
activateExtensionsMap.put(getExtensionClass(name), getExtension(name));
}
if (!activateExtensionsMap.isEmpty()) {
activateExtensions.addAll(activateExtensionsMap.values());
}
return activateExtensions;
}
private boolean isMatchGroup(String group, Set<String> groups) {
if (StringUtils.isEmpty(group)) {
return true;
}
if (CollectionUtils.isNotEmpty(groups)) {
return groups.contains(group);
}
return false;
}
private boolean isActive(String[][] keyPairs, URL url) {
if (keyPairs.length == 0) {
return true;
}
for (String[] keyPair : keyPairs) {
// @Active(value="key1:value1, key2:value2")
String key;
String keyValue = null;
if (keyPair.length > 1) {
key = keyPair[0];
keyValue = keyPair[1];
} else {
key = keyPair[0];
}
String realValue = url.getParameter(key);
if (StringUtils.isEmpty(realValue)) {
realValue = url.getAnyMethodParameter(key);
}
if ((keyValue != null && keyValue.equals(realValue)) || (keyValue == null && ConfigUtils.isNotEmpty(realValue))) {
return true;
}
}
return false;
}
/**
* Get extension's instance. Return <code>null</code> if extension is not found or is not initialized. Pls. note
* that this method will not trigger extension load.
* <p>
* In order to trigger extension load, call {@link #getExtension(String)} instead.
*
* @see #getExtension(String)
*/
@SuppressWarnings("unchecked")
public T getLoadedExtension(String name) {
checkDestroyed();
if (StringUtils.isEmpty(name)) {
throw new IllegalArgumentException("Extension name == null");
}
Holder<Object> holder = getOrCreateHolder(name);
return (T) holder.get();
}
private Holder<Object> getOrCreateHolder(String name) {
Holder<Object> holder = cachedInstances.get(name);
if (holder == null) {
cachedInstances.putIfAbsent(name, new Holder<>());
holder = cachedInstances.get(name);
}
return holder;
}
/**
* Return the list of extensions which are already loaded.
* <p>
* Usually {@link #getSupportedExtensions()} should be called in order to get all extensions.
*
* @see #getSupportedExtensions()
*/
public Set<String> getLoadedExtensions() {
return Collections.unmodifiableSet(new TreeSet<>(cachedInstances.keySet()));
}
@SuppressWarnings("unchecked")
public List<T> getLoadedExtensionInstances() {
checkDestroyed();
List<T> instances = new ArrayList<>();
cachedInstances.values().forEach(holder -> instances.add((T) holder.get()));
return instances;
}
/**
* Find the extension with the given name.
*
* @throws IllegalStateException If the specified extension is not found.
*/
public T getExtension(String name) {
T extension = getExtension(name, true);
if (extension == null) {
throw new IllegalArgumentException("Not find extension: " + name);
}
return extension;
}
@SuppressWarnings("unchecked")
public T getExtension(String name, boolean wrap) {
checkDestroyed();
if (StringUtils.isEmpty(name)) {
throw new IllegalArgumentException("Extension name == null");
}
if ("true".equals(name)) {
return getDefaultExtension();
}
String cacheKey = name;
if (!wrap) {
cacheKey += "_origin";
}
final Holder<Object> holder = getOrCreateHolder(cacheKey);
Object instance = holder.get();
if (instance == null) {
synchronized (holder) {
instance = holder.get();
if (instance == null) {
instance = createExtension(name, wrap);
holder.set(instance);
}
}
}
return (T) instance;
}
/**
* Get the extension by specified name if found, or {@link #getDefaultExtension() returns the default one}
*
* @param name the name of extension
* @return non-null
*/
public T getOrDefaultExtension(String name) {
return containsExtension(name) ? getExtension(name) : getDefaultExtension();
}
/**
* Return default extension, return <code>null</code> if it's not configured.
*/
public T getDefaultExtension() {
getExtensionClasses();
if (StringUtils.isBlank(cachedDefaultName) || "true".equals(cachedDefaultName)) {
return null;
}
return getExtension(cachedDefaultName);
}
public boolean hasExtension(String name) {
checkDestroyed();
if (StringUtils.isEmpty(name)) {
throw new IllegalArgumentException("Extension name == null");
}
Class<?> c = this.getExtensionClass(name);
return c != null;
}
public Set<String> getSupportedExtensions() {
checkDestroyed();
Map<String, Class<?>> classes = getExtensionClasses();
return Collections.unmodifiableSet(new TreeSet<>(classes.keySet()));
}
public Set<T> getSupportedExtensionInstances() {
checkDestroyed();
List<T> instances = new LinkedList<>();
Set<String> supportedExtensions = getSupportedExtensions();
if (CollectionUtils.isNotEmpty(supportedExtensions)) {
for (String name : supportedExtensions) {
instances.add(getExtension(name));
}
}
// sort the Prioritized instances
instances.sort(Prioritized.COMPARATOR);
return new LinkedHashSet<>(instances);
}
/**
* Return default extension name, return <code>null</code> if not configured.
*/
public String getDefaultExtensionName() {
getExtensionClasses();
return cachedDefaultName;
}
/**
* Register new extension via API
*
* @param name extension name
* @param clazz extension class
* @throws IllegalStateException when extension with the same name has already been registered.
*/
public void addExtension(String name, Class<?> clazz) {
checkDestroyed();
getExtensionClasses(); // load classes
if (!type.isAssignableFrom(clazz)) {
throw new IllegalStateException("Input type " +
clazz + " doesn't implement the Extension " + type);
}
if (clazz.isInterface()) {
throw new IllegalStateException("Input type " +
clazz + " can't be interface!");
}
if (!clazz.isAnnotationPresent(Adaptive.class)) {
if (StringUtils.isBlank(name)) {
throw new IllegalStateException("Extension name is blank (Extension " + type + ")!");
}
if (cachedClasses.get().containsKey(name)) {
throw new IllegalStateException("Extension name " +
name + " already exists (Extension " + type + ")!");
}
cachedNames.put(clazz, name);
cachedClasses.get().put(name, clazz);
} else {
if (cachedAdaptiveClass != null) {
throw new IllegalStateException("Adaptive Extension already exists (Extension " + type + ")!");
}
cachedAdaptiveClass = clazz;
}
}
/**
* Replace the existing extension via API
*
* @param name extension name
* @param clazz extension class
* @throws IllegalStateException when extension to be placed doesn't exist
* @deprecated not recommended any longer, and use only when test
*/
@Deprecated
public void replaceExtension(String name, Class<?> clazz) {
checkDestroyed();
getExtensionClasses(); // load classes
if (!type.isAssignableFrom(clazz)) {
throw new IllegalStateException("Input type " +
clazz + " doesn't implement Extension " + type);
}
if (clazz.isInterface()) {
throw new IllegalStateException("Input type " +
clazz + " can't be interface!");
}
if (!clazz.isAnnotationPresent(Adaptive.class)) {
if (StringUtils.isBlank(name)) {
throw new IllegalStateException("Extension name is blank (Extension " + type + ")!");
}
if (!cachedClasses.get().containsKey(name)) {
throw new IllegalStateException("Extension name " +
name + " doesn't exist (Extension " + type + ")!");
}
cachedNames.put(clazz, name);
cachedClasses.get().put(name, clazz);
cachedInstances.remove(name);
} else {
if (cachedAdaptiveClass == null) {
throw new IllegalStateException("Adaptive Extension doesn't exist (Extension " + type + ")!");
}
cachedAdaptiveClass = clazz;
cachedAdaptiveInstance.set(null);
}
}
@SuppressWarnings("unchecked")
public T getAdaptiveExtension() {
checkDestroyed();
Object instance = cachedAdaptiveInstance.get();
if (instance == null) {
if (createAdaptiveInstanceError != null) {
throw new IllegalStateException("Failed to create adaptive instance: " +
createAdaptiveInstanceError.toString(),
createAdaptiveInstanceError);
}
synchronized (cachedAdaptiveInstance) {
instance = cachedAdaptiveInstance.get();
if (instance == null) {
try {
instance = createAdaptiveExtension();
cachedAdaptiveInstance.set(instance);
} catch (Throwable t) {
createAdaptiveInstanceError = t;
throw new IllegalStateException("Failed to create adaptive instance: " + t.toString(), t);
}
}
}
}
return (T) instance;
}
private IllegalStateException findException(String name) {
StringBuilder buf = new StringBuilder("No such extension " + type.getName() + " by name " + name);
int i = 1;
for (Map.Entry<String, IllegalStateException> entry : exceptions.entrySet()) {
if (entry.getKey().toLowerCase().startsWith(name.toLowerCase())) {
if (i == 1) {
buf.append(", possible causes: ");
}
buf.append("\r\n(");
buf.append(i++);
buf.append(") ");
buf.append(entry.getKey());
buf.append(":\r\n");
buf.append(StringUtils.toString(entry.getValue()));
}
}
if (i == 1) {
buf.append(", no related exception was found, please check whether related SPI module is missing.");
}
return new IllegalStateException(buf.toString());
}
@SuppressWarnings("unchecked")
private T createExtension(String name, boolean wrap) {
Class<?> clazz = getExtensionClasses().get(name);
if (clazz == null || unacceptableExceptions.contains(name)) {
throw findException(name);
}
try {
T instance = (T) extensionInstances.get(clazz);
if (instance == null) {
extensionInstances.putIfAbsent(clazz, createExtensionInstance(clazz));
instance = (T) extensionInstances.get(clazz);
instance = postProcessBeforeInitialization(instance, name);
injectExtension(instance);
instance = postProcessAfterInitialization(instance, name);
}
if (wrap) {
List<Class<?>> wrapperClassesList = new ArrayList<>();
if (cachedWrapperClasses != null) {
wrapperClassesList.addAll(cachedWrapperClasses);
wrapperClassesList.sort(WrapperComparator.COMPARATOR);
Collections.reverse(wrapperClassesList);
}
if (CollectionUtils.isNotEmpty(wrapperClassesList)) {
for (Class<?> wrapperClass : wrapperClassesList) {
Wrapper wrapper = wrapperClass.getAnnotation(Wrapper.class);
boolean match = (wrapper == null) ||
((ArrayUtils.isEmpty(wrapper.matches()) || ArrayUtils.contains(wrapper.matches(), name)) &&
!ArrayUtils.contains(wrapper.mismatches(), name));
if (match) {
instance = injectExtension((T) wrapperClass.getConstructor(type).newInstance(instance));
instance = postProcessAfterInitialization(instance, name);
}
}
}
}
// Warning: After an instance of Lifecycle is wrapped by cachedWrapperClasses, it may not still be Lifecycle instance, this application may not invoke the lifecycle.initialize hook.
initExtension(instance);
return instance;
} catch (Throwable t) {
throw new IllegalStateException("Extension instance (name: " + name + ", class: " +
type + ") couldn't be instantiated: " + t.getMessage(), t);
}
}
private Object createExtensionInstance(Class<?> type) throws ReflectiveOperationException {
return instantiationStrategy.instantiate(type);
}
@SuppressWarnings("unchecked")
private T postProcessBeforeInitialization(T instance, String name) throws Exception {
if (extensionPostProcessors != null) {
for (ExtensionPostProcessor processor : extensionPostProcessors) {
instance = (T) processor.postProcessBeforeInitialization(instance, name);
}
}
return instance;
}
@SuppressWarnings("unchecked")
private T postProcessAfterInitialization(T instance, String name) throws Exception {
if (instance instanceof ExtensionAccessorAware) {
((ExtensionAccessorAware) instance).setExtensionAccessor(extensionDirector);
}
if (extensionPostProcessors != null) {
for (ExtensionPostProcessor processor : extensionPostProcessors) {
instance = (T) processor.postProcessAfterInitialization(instance, name);
}
}
return instance;
}
private boolean containsExtension(String name) {
return getExtensionClasses().containsKey(name);
}
private T injectExtension(T instance) {
if (injector == null) {
return instance;
}
try {
for (Method method : instance.getClass().getMethods()) {
if (!isSetter(method)) {
continue;
}
/**
* Check {@link DisableInject} to see if we need auto-injection for this property
*/
if (method.isAnnotationPresent(DisableInject.class)) {
continue;
}
// When spiXXX implements ScopeModelAware, ExtensionAccessorAware,
// the setXXX of ScopeModelAware and ExtensionAccessorAware does not need to be injected
if (method.getDeclaringClass() == ScopeModelAware.class) {
continue;
}
if (instance instanceof ScopeModelAware || instance instanceof ExtensionAccessorAware) {
if (ignoredInjectMethodsDesc.contains(ReflectUtils.getDesc(method))) {
continue;
}
}
Class<?> pt = method.getParameterTypes()[0];
if (ReflectUtils.isPrimitives(pt)) {
continue;
}
try {
String property = getSetterProperty(method);
Object object = injector.getInstance(pt, property);
if (object != null) {
method.invoke(instance, object);
}
} catch (Exception e) {
logger.error("Failed to inject via method " + method.getName()
+ " of interface " + type.getName() + ": " + e.getMessage(), e);
}
}
} catch (Exception e) {
logger.error(e.getMessage(), e);
}
return instance;
}
private void initExtension(T instance) {
if (instance instanceof Lifecycle) {
Lifecycle lifecycle = (Lifecycle) instance;
lifecycle.initialize();
}
}
/**
* get properties name for setter, for instance: setVersion, return "version"
* <p>
* return "", if setter name with length less than 3
*/
private String getSetterProperty(Method method) {
return method.getName().length() > 3 ? method.getName().substring(3, 4).toLowerCase() + method.getName().substring(4) : "";
}
/**
* return true if and only if:
* <p>
* 1, public
* <p>
* 2, name starts with "set"
* <p>
* 3, only has one parameter
*/
private boolean isSetter(Method method) {
return method.getName().startsWith("set")
&& method.getParameterTypes().length == 1
&& Modifier.isPublic(method.getModifiers());
}
private Class<?> getExtensionClass(String name) {
if (type == null) {
throw new IllegalArgumentException("Extension type == null");
}
if (name == null) {
throw new IllegalArgumentException("Extension name == null");
}
return getExtensionClasses().get(name);
}
private Map<String, Class<?>> getExtensionClasses() {
Map<String, Class<?>> classes = cachedClasses.get();
if (classes == null) {
synchronized (cachedClasses) {
classes = cachedClasses.get();
if (classes == null) {
try {
classes = loadExtensionClasses();
} catch (InterruptedException e) {
logger.error("Exception occurred when loading extension class (interface: " + type + ")", e);
throw new IllegalStateException("Exception occurred when loading extension class (interface: " + type + ")", e);
}
cachedClasses.set(classes);
}
}
}
return classes;
}
/**
* synchronized in getExtensionClasses
*/
@SuppressWarnings("deprecation")
private Map<String, Class<?>> loadExtensionClasses() throws InterruptedException {
checkDestroyed();
cacheDefaultExtensionName();
Map<String, Class<?>> extensionClasses = new HashMap<>();
for (LoadingStrategy strategy : strategies) {
loadDirectory(extensionClasses, strategy, type.getName());
// compatible with old ExtensionFactory
if (this.type == ExtensionInjector.class) {
loadDirectory(extensionClasses, strategy, ExtensionFactory.class.getName());
}
}
return extensionClasses;
}
private void loadDirectory(Map<String, Class<?>> extensionClasses, LoadingStrategy strategy, String type) throws InterruptedException {
loadDirectoryInternal(extensionClasses, strategy, type);
try {
String oldType = type.replace("org.apache", "com.alibaba");
if (oldType.equals(type)) {
return;
}
//if class not found,skip try to load resources
ClassUtils.forName(oldType);
loadDirectoryInternal(extensionClasses, strategy, oldType);
} catch (ClassNotFoundException classNotFoundException) {
}
}
/**
* extract and cache default extension name if exists
*/
private void cacheDefaultExtensionName() {
final SPI defaultAnnotation = type.getAnnotation(SPI.class);
if (defaultAnnotation == null) {
return;
}
String value = defaultAnnotation.value();
if ((value = value.trim()).length() > 0) {
String[] names = NAME_SEPARATOR.split(value);
if (names.length > 1) {
throw new IllegalStateException("More than 1 default extension name on extension " + type.getName()
+ ": " + Arrays.toString(names));
}
if (names.length == 1) {
cachedDefaultName = names[0];
}
}
}
private void loadDirectoryInternal(Map<String, Class<?>> extensionClasses, LoadingStrategy loadingStrategy, String type) throws InterruptedException {
String fileName = loadingStrategy.directory() + type;
try {
List<ClassLoader> classLoadersToLoad = new LinkedList<>();
// try to load from ExtensionLoader's ClassLoader first
if (loadingStrategy.preferExtensionClassLoader()) {
ClassLoader extensionLoaderClassLoader = ExtensionLoader.class.getClassLoader();
if (ClassLoader.getSystemClassLoader() != extensionLoaderClassLoader) {
classLoadersToLoad.add(extensionLoaderClassLoader);
}
}
if (specialSPILoadingStrategyMap.containsKey(type)){
String internalDirectoryType = specialSPILoadingStrategyMap.get(type);
//skip to load spi when name don't match
if (!LoadingStrategy.ALL.equals(internalDirectoryType)
&& !internalDirectoryType.equals(loadingStrategy.getName())){
return;
}
classLoadersToLoad.clear();
classLoadersToLoad.add(ExtensionLoader.class.getClassLoader());
}else {
// load from scope model
Set<ClassLoader> classLoaders = scopeModel.getClassLoaders();
if (CollectionUtils.isEmpty(classLoaders)) {
Enumeration<java.net.URL> resources = ClassLoader.getSystemResources(fileName);
if (resources != null) {
while (resources.hasMoreElements()) {
loadResource(extensionClasses, null, resources.nextElement(), loadingStrategy.overridden(),
loadingStrategy.includedPackages(),
loadingStrategy.excludedPackages(),
loadingStrategy.onlyExtensionClassLoaderPackages());
}
}
} else {
classLoadersToLoad.addAll(classLoaders);
}
}
Map<ClassLoader, Set<java.net.URL>> resources = ClassLoaderResourceLoader.loadResources(fileName, classLoadersToLoad);
resources.forEach(((classLoader, urls) -> {
loadFromClass(extensionClasses, loadingStrategy.overridden(), urls, classLoader,
loadingStrategy.includedPackages(),
loadingStrategy.excludedPackages(),
loadingStrategy.onlyExtensionClassLoaderPackages());
}));
} catch (InterruptedException e) {
throw e;
} catch (Throwable t) {
logger.error("Exception occurred when loading extension class (interface: " +
type + ", description file: " + fileName + ").", t);
}
}
private void loadFromClass(Map<String, Class<?>> extensionClasses, boolean overridden, Set<java.net.URL> urls, ClassLoader classLoader,
String[] includedPackages, String[] excludedPackages, String[] onlyExtensionClassLoaderPackages) {
if (CollectionUtils.isNotEmpty(urls)) {
for (java.net.URL url : urls) {
loadResource(extensionClasses, classLoader, url, overridden, includedPackages, excludedPackages, onlyExtensionClassLoaderPackages);
}
}
}
private void loadResource(Map<String, Class<?>> extensionClasses, ClassLoader classLoader,
java.net.URL resourceURL, boolean overridden, String[] includedPackages, String[] excludedPackages, String[] onlyExtensionClassLoaderPackages) {
try {
List<String> newContentList = getResourceContent(resourceURL);
String clazz;
for (String line : newContentList) {
try {
String name = null;
int i = line.indexOf('=');
if (i > 0) {
name = line.substring(0, i).trim();
clazz = line.substring(i + 1).trim();
} else {
clazz = line;
}
if (StringUtils.isNotEmpty(clazz) && !isExcluded(clazz, excludedPackages) && isIncluded(clazz, includedPackages)
&& !isExcludedByClassLoader(clazz, classLoader, onlyExtensionClassLoaderPackages)) {
loadClass(extensionClasses, resourceURL, Class.forName(clazz, true, classLoader), name, overridden);
}
} catch (Throwable t) {
IllegalStateException e = new IllegalStateException("Failed to load extension class (interface: " + type +
", class line: " + line + ") in " + resourceURL + ", cause: " + t.getMessage(), t);
exceptions.put(line, e);
}
}
} catch (Throwable t) {
logger.error("Exception occurred when loading extension class (interface: " +
type + ", class file: " + resourceURL + ") in " + resourceURL, t);
}
}
private List<String> getResourceContent(java.net.URL resourceURL) throws IOException {
Map<java.net.URL, List<String>> urlListMap = urlListMapCache.get();
if (urlListMap == null) {
synchronized (ExtensionLoader.class) {
if ((urlListMap = urlListMapCache.get()) == null) {
urlListMap = new ConcurrentHashMap<>();
urlListMapCache = new SoftReference<>(urlListMap);
}
}
}
List<String> contentList = urlListMap.computeIfAbsent(resourceURL,key->{
List<String> newContentList = new ArrayList<>();
try (BufferedReader reader = new BufferedReader(new InputStreamReader(resourceURL.openStream(), StandardCharsets.UTF_8))) {
String line;
while ((line = reader.readLine()) != null) {
final int ci = line.indexOf('#');
if (ci >= 0) {
line = line.substring(0, ci);
}
line = line.trim();
if (line.length() > 0) {
newContentList.add(line);
}
}
} catch (IOException e) {
throw new RuntimeException(e.getMessage(), e);
}
return newContentList;
});
return contentList;
}
private boolean isIncluded(String className, String... includedPackages) {
if (includedPackages != null && includedPackages.length > 0) {
for (String includedPackage : includedPackages) {
if (className.startsWith(includedPackage + ".")) {
// one match, return true
return true;
}
}
// none matcher match, return false
return false;
}
// matcher is empty, return true
return true;
}
private boolean isExcluded(String className, String... excludedPackages) {
if (excludedPackages != null) {
for (String excludePackage : excludedPackages) {
if (className.startsWith(excludePackage + ".")) {
return true;
}
}
}
return false;
}
private boolean isExcludedByClassLoader(String className, ClassLoader classLoader, String... onlyExtensionClassLoaderPackages) {
if (onlyExtensionClassLoaderPackages != null) {
for (String excludePackage : onlyExtensionClassLoaderPackages) {
if (className.startsWith(excludePackage + ".")) {
// if target classLoader is not ExtensionLoader's classLoader should be excluded
return !Objects.equals(ExtensionLoader.class.getClassLoader(), classLoader);
}
}
}
return false;
}
private void loadClass(Map<String, Class<?>> extensionClasses, java.net.URL resourceURL, Class<?> clazz, String name,
boolean overridden) {
if (!type.isAssignableFrom(clazz)) {
throw new IllegalStateException("Error occurred when loading extension class (interface: " +
type + ", class line: " + clazz.getName() + "), class "
+ clazz.getName() + " is not subtype of interface.");
}
if (clazz.isAnnotationPresent(Adaptive.class)) {
cacheAdaptiveClass(clazz, overridden);
} else if (isWrapperClass(clazz)) {
cacheWrapperClass(clazz);
} else {
if (StringUtils.isEmpty(name)) {
name = findAnnotationName(clazz);
if (name.length() == 0) {
throw new IllegalStateException("No such extension name for the class " + clazz.getName() + " in the config " + resourceURL);
}
}
String[] names = NAME_SEPARATOR.split(name);
if (ArrayUtils.isNotEmpty(names)) {
cacheActivateClass(clazz, names[0]);
for (String n : names) {
cacheName(clazz, n);
saveInExtensionClass(extensionClasses, clazz, n, overridden);
}
}
}
}
/**
* cache name
*/
private void cacheName(Class<?> clazz, String name) {
if (!cachedNames.containsKey(clazz)) {
cachedNames.put(clazz, name);
}
}
/**
* put clazz in extensionClasses
*/
private void saveInExtensionClass(Map<String, Class<?>> extensionClasses, Class<?> clazz, String name, boolean overridden) {
Class<?> c = extensionClasses.get(name);
if (c == null || overridden) {
extensionClasses.put(name, clazz);
} else if (c != clazz) {
// duplicate implementation is unacceptable
unacceptableExceptions.add(name);
String duplicateMsg = "Duplicate extension " + type.getName() + " name " + name + " on " + c.getName() + " and " + clazz.getName();
logger.error(duplicateMsg);
throw new IllegalStateException(duplicateMsg);
}
}
/**
* cache Activate class which is annotated with <code>Activate</code>
* <p>
* for compatibility, also cache class with old alibaba Activate annotation
*/
@SuppressWarnings("deprecation")
private void cacheActivateClass(Class<?> clazz, String name) {
Activate activate = clazz.getAnnotation(Activate.class);
if (activate != null) {
cachedActivates.put(name, activate);
} else {
// support com.alibaba.dubbo.common.extension.Activate
com.alibaba.dubbo.common.extension.Activate oldActivate = clazz.getAnnotation(com.alibaba.dubbo.common.extension.Activate.class);
if (oldActivate != null) {
cachedActivates.put(name, oldActivate);
}
}
}
/**
* cache Adaptive class which is annotated with <code>Adaptive</code>
*/
private void cacheAdaptiveClass(Class<?> clazz, boolean overridden) {
if (cachedAdaptiveClass == null || overridden) {
cachedAdaptiveClass = clazz;
} else if (!cachedAdaptiveClass.equals(clazz)) {
throw new IllegalStateException("More than 1 adaptive class found: "
+ cachedAdaptiveClass.getName()
+ ", " + clazz.getName());
}
}
/**
* cache wrapper class
* <p>
* like: ProtocolFilterWrapper, ProtocolListenerWrapper
*/
private void cacheWrapperClass(Class<?> clazz) {
if (cachedWrapperClasses == null) {
cachedWrapperClasses = new ConcurrentHashSet<>();
}
cachedWrapperClasses.add(clazz);
}
/**
* test if clazz is a wrapper class
* <p>
* which has Constructor with given class type as its only argument
*/
protected boolean isWrapperClass(Class<?> clazz) {
Constructor<?>[] constructors = clazz.getConstructors();
for (Constructor<?> constructor : constructors) {
if (constructor.getParameterTypes().length == 1 && constructor.getParameterTypes()[0] == type) {
return true;
}
}
return false;
}
@SuppressWarnings("deprecation")
private String findAnnotationName(Class<?> clazz) {
Extension extension = clazz.getAnnotation(Extension.class);
if (extension != null) {
return extension.value();
}
String name = clazz.getSimpleName();
if (name.endsWith(type.getSimpleName())) {
name = name.substring(0, name.length() - type.getSimpleName().length());
}
return name.toLowerCase();
}
@SuppressWarnings("unchecked")
private T createAdaptiveExtension() {
try {
T instance = (T) getAdaptiveExtensionClass().newInstance();
instance = postProcessBeforeInitialization(instance, null);
injectExtension(instance);
instance = postProcessAfterInitialization(instance, null);
initExtension(instance);
return instance;
} catch (Exception e) {
throw new IllegalStateException("Can't create adaptive extension " + type + ", cause: " + e.getMessage(), e);
}
}
private Class<?> getAdaptiveExtensionClass() {
getExtensionClasses();
if (cachedAdaptiveClass != null) {
return cachedAdaptiveClass;
}
return cachedAdaptiveClass = createAdaptiveExtensionClass();
}
private Class<?> createAdaptiveExtensionClass() {
// Adaptive Classes' ClassLoader should be the same with Real SPI interface classes' ClassLoader
ClassLoader classLoader = type.getClassLoader();
try {
if (NativeUtils.isNative()) {
return classLoader.loadClass(type.getName() + "$Adaptive");
}
} catch (Throwable ignore) {
}
String code = new AdaptiveClassCodeGenerator(type, cachedDefaultName).generate();
org.apache.dubbo.common.compiler.Compiler compiler = extensionDirector.getExtensionLoader(
org.apache.dubbo.common.compiler.Compiler.class).getAdaptiveExtension();
return compiler.compile(type, code, classLoader);
}
@Override
public String toString() {
return this.getClass().getName() + "[" + type.getName() + "]";
}
private static Properties loadProperties(ClassLoader classLoader, String resourceName) {
Properties properties = new Properties();
if (classLoader != null) {
try {
Enumeration<java.net.URL> resources = classLoader.getResources(resourceName);
while (resources.hasMoreElements()) {
java.net.URL url = resources.nextElement();
Properties props = loadFromUrl(url);
for (Map.Entry<Object, Object> entry : props.entrySet()) {
String key = entry.getKey().toString();
if (properties.containsKey(key)) {
continue;
}
properties.put(key, entry.getValue().toString());
}
}
} catch (IOException ex) {
logger.error("load properties failed.", ex);
}
}
return properties;
}
private static Properties loadFromUrl(java.net.URL url) {
Properties properties = new Properties();
InputStream is = null;
try {
is = url.openStream();
properties.load(is);
} catch (IOException e) {
// ignore
} finally {
if (is != null) {
try {
is.close();
} catch (IOException e) {
// ignore
}
}
}
return properties;
}
}
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相关文章
dubbo AdaptiveClassCodeGenerator 源码
dubbo DubboInternalLoadingStrategy 源码
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