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com.alibaba.dubbo.common.extension.ExtensionLoader Maven / Gradle / Ivy
/*
* Copyright 1999-2011 Alibaba Group.
*
* 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 com.alibaba.dubbo.common.extension;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.net.ProtocolException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.regex.Pattern;
import com.alibaba.dubbo.common.Constants;
import com.alibaba.dubbo.common.URL;
import com.alibaba.dubbo.common.extension.support.ActivateComparator;
import com.alibaba.dubbo.common.logger.Logger;
import com.alibaba.dubbo.common.logger.LoggerFactory;
import com.alibaba.dubbo.common.utils.ConcurrentHashSet;
import com.alibaba.dubbo.common.utils.ConfigUtils;
import com.alibaba.dubbo.common.utils.Holder;
import com.alibaba.dubbo.common.utils.StringUtils;
/**
* Dubbo使用的扩展点获取。
*
*
* 自动注入关联扩展点。
* 自动Wrap上扩展点的Wrap类。
* 缺省获得的的扩展点是一个Adaptive Instance。
*
*
* @see JDK5.0的自动发现机制实现
*
* @author william.liangf
* @author ding.lid
*
* @see SPI
* @see Adaptive
* @see Activate
*/
public class ExtensionLoader {
private static final Logger logger = LoggerFactory
.getLogger(ExtensionLoader.class);
private static final String SERVICES_DIRECTORY = "META-INF/services/";
private static final String DUBBO_DIRECTORY = "META-INF/dubbo/";
private static final String DUBBO_INTERNAL_DIRECTORY = DUBBO_DIRECTORY
+ "internal/";
private static final Pattern NAME_SEPARATOR = Pattern
.compile("\\s*[,]+\\s*");
private static final ConcurrentMap, ExtensionLoader> EXTENSION_LOADERS = new ConcurrentHashMap, ExtensionLoader>();
private static final ConcurrentMap, Object> EXTENSION_INSTANCES = new ConcurrentHashMap, Object>();
// ==============================
private final Class type;
private final ExtensionFactory objectFactory;
// 缓存当前扩展加载器发现的扩展类
private final ConcurrentMap, String> cachedNames = new ConcurrentHashMap, String>();
// 缓存当前加载器的所有扩展累
// cachedNames和cachedClasses类似，只是它们关注点不一样，cachedNames关注的是一个类可以对应多个name，但是类不能重复，而cachedClasses是多个name可以对应多个类，但是name不能重复
private final Holder>> cachedClasses = new Holder>>();
// 缓存当前ExtensionLoader的所有Activates类型的扩展
private final Map cachedActivates = new ConcurrentHashMap();
// 当前扩展的适配器类
private volatile Class cachedAdaptiveClass = null;
// 缓存已经被实例化的扩展，key是扩展名，value是扩展实体对象
private final ConcurrentMap> cachedInstances = new ConcurrentHashMap>();
// 通过SPI来制定当前扩展的默认扩展名称
private String cachedDefaultName;
// 适配器实体
private final Holder cachedAdaptiveInstance = new Holder();
// 初始化适配器实体异常类
private volatile Throwable createAdaptiveInstanceError;
// 记录是否是wrapper的类，构造函数需要传入当前扩展实体
private Set> cachedWrapperClasses;
// 扩展初始化异常缓存容器
private Map exceptions = new ConcurrentHashMap();
private static boolean withExtensionAnnotation(Class type) {
return type.isAnnotationPresent(SPI.class);
}
@SuppressWarnings("unchecked")
public static ExtensionLoader getExtensionLoader(Class type) {
if (type == null)
throw new IllegalArgumentException("Extension type == null");
if (!type.isInterface()) {
throw new IllegalArgumentException("Extension type(" + type
+ ") is not interface!");
}
if (!withExtensionAnnotation(type)) {
throw new IllegalArgumentException("Extension type(" + type
+ ") is not extension, because WITHOUT @"
+ SPI.class.getSimpleName() + " Annotation!");
}
ExtensionLoader loader = (ExtensionLoader) EXTENSION_LOADERS
.get(type);
if (loader == null) {
EXTENSION_LOADERS.putIfAbsent(type, new ExtensionLoader(type));
loader = (ExtensionLoader) EXTENSION_LOADERS.get(type);
}
return loader;
}
private ExtensionLoader(Class type) {
this.type = type;
objectFactory = (type == ExtensionFactory.class ? null
: ExtensionLoader.getExtensionLoader(ExtensionFactory.class)
.getAdaptiveExtension());
}
public String getExtensionName(T extensionInstance) {
return getExtensionName(extensionInstance.getClass());
}
public String getExtensionName(Class extensionClass) {
return cachedNames.get(extensionClass);
}
/**
* This is equivalent to
*
*
* 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(URL, String, String)
*/
public List getActivateExtension(URL url, String key) {
return getActivateExtension(url, key, null);
}
/**
* This is equivalent to
*
*
* getActivateExtension(url, values, null);
*
*
* @see #getActivateExtension(URL, String[],
* String)
* @param url
* url
* @param values
* extension point names
* @return extension list which are activated
*/
public List getActivateExtension(URL url, String[] values) {
return getActivateExtension(url, values, null);
}
/**
* This is equivalent to
*
*
* getActivateExtension(url, url.getParameter(key).split(","), null);
*
*
* @see #getActivateExtension(URL, String[],
* String)
* @param url
* url
* @param key
* url parameter key which used to get extension point names
* @param group
* group
* @return extension list which are activated.
*/
public List getActivateExtension(URL url, String key, String group) {
String value = url.getParameter(key);
return getActivateExtension(url,
value == null || value.length() == 0 ? null
: Constants.COMMA_SPLIT_PATTERN.split(value), group);
}
/**
* Get activate extensions.
*
* @see Activate
* @param url
* url
* @param values
* extension point names
* @param group
* group
* @return extension list which are activated
*/
public List getActivateExtension(URL url, String[] values, String group) {
List exts = new ArrayList();
List names = values == null ? new ArrayList(0) : Arrays
.asList(values);
if (!names.contains(Constants.REMOVE_VALUE_PREFIX
+ Constants.DEFAULT_KEY)) {
getExtensionClasses();
for (Map.Entry entry : cachedActivates.entrySet()) {
String name = entry.getKey();
Activate activate = entry.getValue();
if (isMatchGroup(group, activate.group())) {
T ext = getExtension(name);
if (!names.contains(name)
&& !names.contains(Constants.REMOVE_VALUE_PREFIX
+ name) && isActive(activate, url)) {
exts.add(ext);
}
}
}
Collections.sort(exts, ActivateComparator.COMPARATOR);
}
List usrs = new ArrayList();
for (int i = 0; i < names.size(); i++) {
String name = names.get(i);
if (!name.startsWith(Constants.REMOVE_VALUE_PREFIX)
&& !names.contains(Constants.REMOVE_VALUE_PREFIX + name)) {
if (Constants.DEFAULT_KEY.equals(name)) {
if (usrs.size() > 0) {
exts.addAll(0, usrs);
usrs.clear();
}
} else {
T ext = getExtension(name);
usrs.add(ext);
}
}
}
if (usrs.size() > 0) {
exts.addAll(usrs);
}
return exts;
}
private boolean isMatchGroup(String group, String[] groups) {
if (group == null || group.length() == 0) {
return true;
}
if (groups != null && groups.length > 0) {
for (String g : groups) {
if (group.equals(g)) {
return true;
}
}
}
return false;
}
private boolean isActive(Activate activate, URL url) {
String[] keys = activate.value();
if (keys == null || keys.length == 0) {
return true;
}
for (String key : keys) {
for (Map.Entry entry : url.getParameters()
.entrySet()) {
String k = entry.getKey();
String v = entry.getValue();
if ((k.equals(key) || k.endsWith("." + key))
&& ConfigUtils.isNotEmpty(v)) {
return true;
}
}
}
return false;
}
/**
* 返回扩展点实例，如果没有指定的扩展点或是还没加载（即实例化）则返回null。注意：此方法不会触发扩展点的加载。
*
* 一般应该调用{@link #getExtension(String)}方法获得扩展，这个方法会触发扩展点加载。
*
* @see #getExtension(String)
*/
@SuppressWarnings("unchecked")
public T getLoadedExtension(String name) {
if (name == null || name.length() == 0)
throw new IllegalArgumentException("Extension name == null");
Holder holder = cachedInstances.get(name);
if (holder == null) {
cachedInstances.putIfAbsent(name, new Holder());
holder = cachedInstances.get(name);
}
return (T) holder.get();
}
/**
* 返回已经加载的扩展点的名字。
*
* 一般应该调用{@link #getSupportedExtensions()}方法获得扩展，这个方法会返回所有的扩展点。
*
* @see #getSupportedExtensions()
*/
public Set getLoadedExtensions() {
return Collections.unmodifiableSet(new TreeSet(cachedInstances
.keySet()));
}
/**
* 返回指定名字的扩展。如果指定名字的扩展不存在，则抛异常 {@link IllegalStateException}.
*
* @param name
* @return
*/
@SuppressWarnings("unchecked")
public T getExtension(String name) {
if (name == null || name.length() == 0)
throw new IllegalArgumentException("Extension name == null");
if ("true".equals(name)) {
return getDefaultExtension();
}
Holder holder = cachedInstances.get(name);
if (holder == null) {
cachedInstances.putIfAbsent(name, new Holder());
holder = cachedInstances.get(name);
}
Object instance = holder.get();
if (instance == null) {
synchronized (holder) {
instance = holder.get();
if (instance == null) {
instance = createExtension(name);
holder.set(instance);
}
}
}
return (T) instance;
}
/**
* 返回缺省的扩展，如果没有设置则返回null。
*/
public T getDefaultExtension() {
getExtensionClasses();
if (null == cachedDefaultName || cachedDefaultName.length() == 0
|| "true".equals(cachedDefaultName)) {
return null;
}
return getExtension(cachedDefaultName);
}
public boolean hasExtension(String name) {
if (name == null || name.length() == 0)
throw new IllegalArgumentException("Extension name == null");
try {
return getExtensionClass(name) != null;
} catch (Throwable t) {
return false;
}
}
public Set getSupportedExtensions() {
Map> clazzes = getExtensionClasses();
return Collections
.unmodifiableSet(new TreeSet(clazzes.keySet()));
}
/**
* 返回缺省的扩展点名，如果没有设置缺省则返回null。
*/
public String getDefaultExtensionName() {
getExtensionClasses();
return cachedDefaultName;
}
/**
* 编程方式添加新扩展点。
*
* @param name
* 扩展点名
* @param clazz
* 扩展点类
* @throws IllegalStateException
* 要添加扩展点名已经存在。
*/
public void addExtension(String name, Class clazz) {
getExtensionClasses(); // load classes
if (!type.isAssignableFrom(clazz)) {
throw new IllegalStateException("Input type " + clazz
+ "not implement Extension " + type);
}
if (clazz.isInterface()) {
throw new IllegalStateException("Input type " + clazz
+ "can not 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 existed(Extension " + type + ")!");
}
cachedNames.put(clazz, name);
cachedClasses.get().put(name, clazz);
} else {
if (cachedAdaptiveClass != null) {
throw new IllegalStateException(
"Adaptive Extension already existed(Extension " + type
+ ")!");
}
cachedAdaptiveClass = clazz;
}
}
/**
* 编程方式添加替换已有扩展点。
*
* @param name
* 扩展点名
* @param clazz
* 扩展点类
* @throws IllegalStateException
* 要添加扩展点名已经存在。
* @deprecated 不推荐应用使用，一般只在测试时可以使用
*/
@Deprecated
public void replaceExtension(String name, Class clazz) {
getExtensionClasses(); // load classes
if (!type.isAssignableFrom(clazz)) {
throw new IllegalStateException("Input type " + clazz
+ "not implement Extension " + type);
}
if (clazz.isInterface()) {
throw new IllegalStateException("Input type " + clazz
+ "can not 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
+ " not existed(Extension " + type + ")!");
}
cachedNames.put(clazz, name);
cachedClasses.get().put(name, clazz);
cachedInstances.remove(name);
} else {
if (cachedAdaptiveClass == null) {
throw new IllegalStateException(
"Adaptive Extension not existed(Extension " + type
+ ")!");
}
cachedAdaptiveClass = clazz;
cachedAdaptiveInstance.set(null);
}
}
@SuppressWarnings("unchecked")
public T getAdaptiveExtension() {
Object instance = cachedAdaptiveInstance.get();
if (instance == null) {
if (createAdaptiveInstanceError == null) {
synchronized (cachedAdaptiveInstance) {
instance = cachedAdaptiveInstance.get();
if (instance == null) {
try {
instance = createAdaptiveExtension();
cachedAdaptiveInstance.set(instance);
} catch (Throwable t) {
createAdaptiveInstanceError = t;
throw new IllegalStateException(
"fail to create adaptive instance: "
+ t.toString(), t);
}
}
}
} else {
throw new IllegalStateException(
"fail to create adaptive instance: "
+ createAdaptiveInstanceError.toString(),
createAdaptiveInstanceError);
}
}
return (T) instance;
}
private IllegalStateException findException(String name) {
for (Map.Entry entry : exceptions
.entrySet()) {
if (entry.getKey().toLowerCase().contains(name.toLowerCase())) {
return entry.getValue();
}
}
StringBuilder buf = new StringBuilder("No such extension "
+ type.getName() + " by name " + name);
int i = 1;
for (Map.Entry entry : exceptions
.entrySet()) {
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()));
}
return new IllegalStateException(buf.toString());
}
@SuppressWarnings("unchecked")
private T createExtension(String name) {
Class clazz = getExtensionClasses().get(name);
if (clazz == null) {
throw findException(name);
}
try {
T instance = (T) EXTENSION_INSTANCES.get(clazz);
if (instance == null) {
EXTENSION_INSTANCES.putIfAbsent(clazz, (T) clazz.newInstance());
instance = (T) EXTENSION_INSTANCES.get(clazz);
}
injectExtension(instance);
Set> wrapperClasses = cachedWrapperClasses;
if (wrapperClasses != null && wrapperClasses.size() > 0) {
for (Class wrapperClass : wrapperClasses) {
instance = injectExtension((T) wrapperClass.getConstructor(
type).newInstance(instance));
}
}
return instance;
} catch (Throwable t) {
throw new IllegalStateException("Extension instance(name: " + name
+ ", class: " + type + ") could not be instantiated: "
+ t.getMessage(), t);
}
}
private T injectExtension(T instance) {
try {
if (objectFactory != null) {
for (Method method : instance.getClass().getMethods()) {
if (method.getName().startsWith("set")
&& method.getParameterTypes().length == 1
&& Modifier.isPublic(method.getModifiers())) {
Class pt = method.getParameterTypes()[0];
try {
String property = method.getName().length() > 3 ? method
.getName().substring(3, 4).toLowerCase()
+ method.getName().substring(4)
: "";
Object object = objectFactory.getExtension(pt,
property);
if (object != null) {
method.invoke(instance, object);
}
} catch (Exception e) {
logger.error(
"fail to inject via method "
+ method.getName()
+ " of interface " + type.getName()
+ ": " + e.getMessage(), e);
}
}
}
}
} catch (Exception e) {
logger.error(e.getMessage(), e);
}
return instance;
}
private Class getExtensionClass(String name) {
if (type == null)
throw new IllegalArgumentException("Extension type == null");
if (name == null)
throw new IllegalArgumentException("Extension name == null");
Class clazz = getExtensionClasses().get(name);
if (clazz == null)
throw new IllegalStateException("No such extension \"" + name
+ "\" for " + type.getName() + "!");
return clazz;
}
private Map> getExtensionClasses() {
Map> classes = cachedClasses.get();
if (classes == null) {
synchronized (cachedClasses) {
classes = cachedClasses.get();
if (classes == null) {
classes = loadExtensionClasses();
cachedClasses.set(classes);
}
}
}
return classes;
}
// 此方法已经getExtensionClasses方法同步过。
private Map> loadExtensionClasses() {
final SPI defaultAnnotation = type.getAnnotation(SPI.class);
if (defaultAnnotation != null) {
String value = defaultAnnotation.value();
if (value != null && (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];
}
}
Map> extensionClasses = new HashMap>();
loadFile(extensionClasses, DUBBO_INTERNAL_DIRECTORY);
loadFile(extensionClasses, DUBBO_DIRECTORY);
loadFile(extensionClasses, SERVICES_DIRECTORY);
return extensionClasses;
}
private void loadFile(Map> extensionClasses, String dir) {
String fileName = dir + type.getName();
try {
Enumeration urls;
ClassLoader classLoader = findClassLoader();
if (classLoader != null) {
urls = classLoader.getResources(fileName);
} else {
urls = ClassLoader.getSystemResources(fileName);
}
if (urls != null) {
while (urls.hasMoreElements()) {
java.net.URL url = urls.nextElement();
try {
BufferedReader reader = new BufferedReader(
new InputStreamReader(url.openStream(), "utf-8"));
try {
String line = null;
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) {
try {
String name = null;
int i = line.indexOf('=');
if (i > 0) {
name = line.substring(0, i).trim();
line = line.substring(i + 1).trim();
}
if (line.length() > 0) {
Class clazz = Class.forName(
line, true, classLoader);
if (!type.isAssignableFrom(clazz)) {
throw new IllegalStateException(
"Error when load extension class(interface: "
+ type
+ ", class line: "
+ clazz.getName()
+ "), class "
+ clazz.getName()
+ "is not subtype of interface.");
}
if (clazz
.isAnnotationPresent(Adaptive.class)) {
if (cachedAdaptiveClass == null) {
cachedAdaptiveClass = clazz;
} else if (!cachedAdaptiveClass
.equals(clazz)) {
throw new IllegalStateException(
"More than 1 adaptive class found: "
+ cachedAdaptiveClass
.getClass()
.getName()
+ ", "
+ clazz.getClass()
.getName());
}
} else {
try {
clazz.getConstructor(type);
Set> wrappers = cachedWrapperClasses;
if (wrappers == null) {
cachedWrapperClasses = new ConcurrentHashSet>();
wrappers = cachedWrapperClasses;
}
wrappers.add(clazz);
} catch (NoSuchMethodException e) {
clazz.getConstructor();
if (name == null
|| name.length() == 0) {
name = findAnnotationName(clazz);
if (name == null
|| name.length() == 0) {
if (clazz
.getSimpleName()
.length() > type
.getSimpleName()
.length()
&& clazz.getSimpleName()
.endsWith(
type.getSimpleName())) {
name = clazz
.getSimpleName()
.substring(
0,
clazz.getSimpleName()
.length()
- type.getSimpleName()
.length())
.toLowerCase();
} else {
throw new IllegalStateException(
"No such extension name for the class "
+ clazz.getName()
+ " in the config "
+ url);
}
}
}
String[] names = NAME_SEPARATOR
.split(name);
if (names != null
&& names.length > 0) {
Activate activate = clazz
.getAnnotation(Activate.class);
if (activate != null) {
cachedActivates
.put(names[0],
activate);
}
for (String n : names) {
if (!cachedNames
.containsKey(clazz)) {
cachedNames
.put(clazz,
n);
}
Class c = extensionClasses
.get(n);
if (c == null) {
extensionClasses
.put(n,
clazz);
} else if (c != clazz) {
throw new IllegalStateException(
"Duplicate extension "
+ type.getName()
+ " name "
+ n
+ " on "
+ c.getName()
+ " and "
+ clazz.getName());
}
}
}
}
}
}
} catch (Throwable t) {
IllegalStateException e = new IllegalStateException(
"Failed to load extension class(interface: "
+ type
+ ", class line: "
+ line + ") in " + url
+ ", cause: "
+ t.getMessage(), t);
exceptions.put(line, e);
}
}
} // end of while read lines
} finally {
reader.close();
}
} catch (Throwable t) {
logger.error(
"Exception when load extension class(interface: "
+ type + ", class file: " + url
+ ") in " + url, t);
}
} // end of while urls
}
} catch (Throwable t) {
logger.error("Exception when load extension class(interface: "
+ type + ", description file: " + fileName + ").", t);
}
}
@SuppressWarnings("deprecation")
private String findAnnotationName(Class clazz) {
com.alibaba.dubbo.common.Extension extension = clazz
.getAnnotation(com.alibaba.dubbo.common.Extension.class);
if (extension == null) {
String name = clazz.getSimpleName();
if (name.endsWith(type.getSimpleName())) {
name = name.substring(0, name.length()
- type.getSimpleName().length());
}
return name.toLowerCase();
}
return extension.value();
}
@SuppressWarnings("unchecked")
private T createAdaptiveExtension() {
try {
return injectExtension((T) getAdaptiveExtensionClass()
.newInstance());
} catch (Exception e) {
throw new IllegalStateException(
"Can not create adaptive extenstion " + type + ", cause: "
+ e.getMessage(), e);
}
}
private Class getAdaptiveExtensionClass() {
getExtensionClasses();
if (cachedAdaptiveClass != null) {
return cachedAdaptiveClass;
}
return cachedAdaptiveClass = createAdaptiveExtensionClass();
}
private Class createAdaptiveExtensionClass() {
String code = createAdaptiveExtensionClassCode();
ClassLoader classLoader = findClassLoader();
com.alibaba.dubbo.common.compiler.Compiler compiler = ExtensionLoader
.getExtensionLoader(
com.alibaba.dubbo.common.compiler.Compiler.class)
.getAdaptiveExtension();
return compiler.compile(code, classLoader);
}
private String createAdaptiveExtensionClassCode() {
StringBuilder codeBuidler = new StringBuilder();
Method[] methods = type.getMethods();
boolean hasAdaptiveAnnotation = false;
for (Method m : methods) {
if (m.isAnnotationPresent(Adaptive.class)) {
hasAdaptiveAnnotation = true;
break;
}
}
// 完全没有Adaptive方法，则不需要生成Adaptive类
if (!hasAdaptiveAnnotation)
throw new IllegalStateException("No adaptive method on extension "
+ type.getName() + ", refuse to create the adaptive class!");
codeBuidler.append("package " + type.getPackage().getName() + ";");
codeBuidler.append("\nimport " + ExtensionLoader.class.getName() + ";");
codeBuidler
.append("\npublic class " + type.getSimpleName() + "$Adpative"
+ " implements " + type.getCanonicalName() + " {");
for (Method method : methods) {
Class rt = method.getReturnType();
Class[] pts = method.getParameterTypes();
Class[] ets = method.getExceptionTypes();
Adaptive adaptiveAnnotation = method.getAnnotation(Adaptive.class);
StringBuilder code = new StringBuilder(512);
if (adaptiveAnnotation == null) {
code.append("throw new UnsupportedOperationException(\"method ")
.append(method.toString()).append(" of interface ")
.append(type.getName())
.append(" is not adaptive method!\");");
} else {
int urlTypeIndex = -1;
//检查是否是URL类型的参数
for (int i = 0; i < pts.length; ++i) {
if (pts[i].equals(URL.class)) {
urlTypeIndex = i;
break;
}
}
// 有类型为URL的参数
if (urlTypeIndex != -1) {
// Null Point check
String s = String
.format("\nif (arg%d == null) throw new IllegalArgumentException(\"url == null\");",
urlTypeIndex);
code.append(s);
s = String.format("\n%s url = arg%d;", URL.class.getName(),
urlTypeIndex);
code.append(s);
}
// 参数没有URL类型
else {
String attribMethod = null;
// 找到参数的URL属性
LBL_PTS: for (int i = 0; i < pts.length; ++i) {
Method[] ms = pts[i].getMethods();
for (Method m : ms) {
String name = m.getName();
if ((name.startsWith("get") || name.length() > 3)
&& Modifier.isPublic(m.getModifiers())
&& !Modifier.isStatic(m.getModifiers())
&& m.getParameterTypes().length == 0
&& m.getReturnType() == URL.class) {
urlTypeIndex = i;
attribMethod = name;
break LBL_PTS;
}
}
}
if (attribMethod == null) {
throw new IllegalStateException(
"fail to create adative class for interface "
+ type.getName()
+ ": not found url parameter or url attribute in parameters of method "
+ method.getName());
}
// Null point check
String s = String
.format("\nif (arg%d == null) throw new IllegalArgumentException(\"%s argument == null\");",
urlTypeIndex, pts[urlTypeIndex].getName());
code.append(s);
s = String
.format("\nif (arg%d.%s() == null) throw new IllegalArgumentException(\"%s argument %s() == null\");",
urlTypeIndex, attribMethod,
pts[urlTypeIndex].getName(), attribMethod);
code.append(s);
s = String.format("%s url = arg%d.%s();",
URL.class.getName(), urlTypeIndex, attribMethod);
code.append(s);
}
String[] value = adaptiveAnnotation.value();
// 没有设置Key，则使用“扩展点接口名的点分隔 作为Key
if (value.length == 0) {
char[] charArray = type.getSimpleName().toCharArray();
StringBuilder sb = new StringBuilder(128);
for (int i = 0; i < charArray.length; i++) {
if (Character.isUpperCase(charArray[i])) {
if (i != 0) {
sb.append(".");
}
sb.append(Character.toLowerCase(charArray[i]));
} else {
sb.append(charArray[i]);
}
}
value = new String[] { sb.toString() };
}
boolean hasInvocation = false;
for (int i = 0; i < pts.length; ++i) {
if (pts[i].getName().equals(
"com.alibaba.dubbo.rpc.Invocation")) {
// Null Point check
String s = String
.format("\nif (arg%d == null) throw new IllegalArgumentException(\"invocation == null\");",
i);
code.append(s);
s = String.format(
"\nString methodName = arg%d.getMethodName();",
i);
code.append(s);
hasInvocation = true;
break;
}
}
String defaultExtName = cachedDefaultName;
String getNameCode = null;
for (int i = value.length - 1; i >= 0; --i) {
if (i == value.length - 1) {
if (null != defaultExtName) {
if (!"protocol".equals(value[i]))
if (hasInvocation)
getNameCode = String
.format("url.getMethodParameter(methodName, \"%s\", \"%s\")",
value[i], defaultExtName);
else
getNameCode = String.format(
"url.getParameter(\"%s\", \"%s\")",
value[i], defaultExtName);
else
getNameCode = String
.format("( url.getProtocol() == null ? \"%s\" : url.getProtocol() )",
defaultExtName);
} else {
if (!"protocol".equals(value[i]))
if (hasInvocation)
getNameCode = String
.format("url.getMethodParameter(methodName, \"%s\", \"%s\")",
value[i], defaultExtName);
else
getNameCode = String.format(
"url.getParameter(\"%s\")",
value[i]);
else
getNameCode = "url.getProtocol()";
}
} else {
if (!"protocol".equals(value[i]))
if (hasInvocation)
getNameCode = String
.format("url.getMethodParameter(methodName, \"%s\", \"%s\")",
value[i], defaultExtName);
else
getNameCode = String.format(
"url.getParameter(\"%s\", %s)",
value[i], getNameCode);
else
getNameCode = String
.format("url.getProtocol() == null ? (%s) : url.getProtocol()",
getNameCode);
}
}
code.append("\nString extName = ").append(getNameCode)
.append(";");
// check extName == null?
String s = String
.format("\nif(extName == null) "
+ "throw new IllegalStateException(\"Fail to get extension(%s) name from url(\" + url.toString() + \") use keys(%s)\");",
type.getName(), Arrays.toString(value));
code.append(s);
s = String
.format("\n%s extension = (% 0) {
codeBuidler.append(", ");
}
codeBuidler.append(pts[i].getCanonicalName());
codeBuidler.append(" ");
codeBuidler.append("arg" + i);
}
codeBuidler.append(")");
if (ets.length > 0) {
codeBuidler.append(" throws ");
for (int i = 0; i < ets.length; i++) {
if (i > 0) {
codeBuidler.append(", ");
}
codeBuidler.append(ets[i].getCanonicalName());
}
}
codeBuidler.append(" {");
codeBuidler.append(code.toString());
codeBuidler.append("\n}");
}
codeBuidler.append("\n}");
if (logger.isDebugEnabled()) {
logger.debug(codeBuidler.toString());
}
return codeBuidler.toString();
}
private static ClassLoader findClassLoader() {
return ExtensionLoader.class.getClassLoader();
}
@Override
public String toString() {
return this.getClass().getName() + "[" + type.getName() + "]";
}
}
