dubbo AdaptiveClassCodeGenerator 源码
dubbo AdaptiveClassCodeGenerator 代码
文件路径：/dubbo-common/src/main/java/org/apache/dubbo/common/extension/AdaptiveClassCodeGenerator.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.URL;
import org.apache.dubbo.common.logger.Logger;
import org.apache.dubbo.common.logger.LoggerFactory;
import org.apache.dubbo.common.utils.StringUtils;
import org.apache.dubbo.rpc.model.ScopeModel;
import org.apache.dubbo.rpc.model.ScopeModelUtil;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
/**
* Code generator for Adaptive class
*/
public class AdaptiveClassCodeGenerator {
private static final Logger logger = LoggerFactory.getLogger(AdaptiveClassCodeGenerator.class);
private static final String CLASS_NAME_INVOCATION = "org.apache.dubbo.rpc.Invocation";
private static final String CODE_PACKAGE = "package %s;\n";
private static final String CODE_IMPORTS = "import %s;\n";
private static final String CODE_CLASS_DECLARATION = "public class %s$Adaptive implements %s {\n";
private static final String CODE_METHOD_DECLARATION = "public %s %s(%s) %s {\n%s}\n";
private static final String CODE_METHOD_ARGUMENT = "%s arg%d";
private static final String CODE_METHOD_THROWS = "throws %s";
private static final String CODE_UNSUPPORTED = "throw new UnsupportedOperationException(\"The method %s of interface %s is not adaptive method!\");\n";
private static final String CODE_URL_NULL_CHECK = "if (arg%d == null) throw new IllegalArgumentException(\"url == null\");\n%s url = arg%d;\n";
private static final String CODE_EXT_NAME_ASSIGNMENT = "String extName = %s;\n";
private static final String CODE_EXT_NAME_NULL_CHECK = "if(extName == null) "
+ "throw new IllegalStateException(\"Failed to get extension (%s) name from url (\" + url.toString() + \") use keys(%s)\");\n";
private static final String CODE_INVOCATION_ARGUMENT_NULL_CHECK = "if (arg%d == null) throw new IllegalArgumentException(\"invocation == null\"); "
+ "String methodName = arg%d.getMethodName();\n";
private static final String CODE_SCOPE_MODEL_ASSIGNMENT = "ScopeModel scopeModel = ScopeModelUtil.getOrDefault(url.getScopeModel(), %s.class);\n";
private static final String CODE_EXTENSION_ASSIGNMENT = "%s extension = (%<s)scopeModel.getExtensionLoader(%s.class).getExtension(extName);\n";
private static final String CODE_EXTENSION_METHOD_INVOKE_ARGUMENT = "arg%d";
private final Class<?> type;
private String defaultExtName;
public AdaptiveClassCodeGenerator(Class<?> type, String defaultExtName) {
this.type = type;
this.defaultExtName = defaultExtName;
}
/**
* test if given type has at least one method annotated with <code>Adaptive</code>
*/
private boolean hasAdaptiveMethod() {
return Arrays.stream(type.getMethods()).anyMatch(m -> m.isAnnotationPresent(Adaptive.class));
}
/**
* generate and return class code
*/
public String generate() {
return this.generate(false);
}
/**
* generate and return class code
* @param sort - whether sort methods
*/
public String generate(boolean sort) {
// no need to generate adaptive class since there's no adaptive method found.
if (!hasAdaptiveMethod()) {
throw new IllegalStateException("No adaptive method exist on extension " + type.getName() + ", refuse to create the adaptive class!");
}
StringBuilder code = new StringBuilder();
code.append(generatePackageInfo());
code.append(generateImports());
code.append(generateClassDeclaration());
Method[] methods = type.getMethods();
if (sort) {
Arrays.sort(methods, Comparator.comparing(Method::toString));
}
for (Method method : methods) {
code.append(generateMethod(method));
}
code.append('}');
if (logger.isDebugEnabled()) {
logger.debug(code.toString());
}
return code.toString();
}
/**
* generate package info
*/
private String generatePackageInfo() {
return String.format(CODE_PACKAGE, type.getPackage().getName());
}
/**
* generate imports
*/
private String generateImports() {
StringBuilder builder = new StringBuilder();
builder.append(String.format(CODE_IMPORTS, ScopeModel.class.getName()));
builder.append(String.format(CODE_IMPORTS, ScopeModelUtil.class.getName()));
return builder.toString();
}
/**
* generate class declaration
*/
private String generateClassDeclaration() {
return String.format(CODE_CLASS_DECLARATION, type.getSimpleName(), type.getCanonicalName());
}
/**
* generate method not annotated with Adaptive with throwing unsupported exception
*/
private String generateUnsupported(Method method) {
return String.format(CODE_UNSUPPORTED, method, type.getName());
}
/**
* get index of parameter with type URL
*/
private int getUrlTypeIndex(Method method) {
int urlTypeIndex = -1;
Class<?>[] pts = method.getParameterTypes();
for (int i = 0; i < pts.length; ++i) {
if (pts[i].equals(URL.class)) {
urlTypeIndex = i;
break;
}
}
return urlTypeIndex;
}
/**
* generate method declaration
*/
private String generateMethod(Method method) {
String methodReturnType = method.getReturnType().getCanonicalName();
String methodName = method.getName();
String methodContent = generateMethodContent(method);
String methodArgs = generateMethodArguments(method);
String methodThrows = generateMethodThrows(method);
return String.format(CODE_METHOD_DECLARATION, methodReturnType, methodName, methodArgs, methodThrows, methodContent);
}
/**
* generate method arguments
*/
private String generateMethodArguments(Method method) {
Class<?>[] pts = method.getParameterTypes();
return IntStream.range(0, pts.length)
.mapToObj(i -> String.format(CODE_METHOD_ARGUMENT, pts[i].getCanonicalName(), i))
.collect(Collectors.joining(", "));
}
/**
* generate method throws
*/
private String generateMethodThrows(Method method) {
Class<?>[] ets = method.getExceptionTypes();
if (ets.length > 0) {
String list = Arrays.stream(ets).map(Class::getCanonicalName).collect(Collectors.joining(", "));
return String.format(CODE_METHOD_THROWS, list);
} else {
return "";
}
}
/**
* generate method URL argument null check
*/
private String generateUrlNullCheck(int index) {
return String.format(CODE_URL_NULL_CHECK, index, URL.class.getName(), index);
}
/**
* generate method content
*/
private String generateMethodContent(Method method) {
Adaptive adaptiveAnnotation = method.getAnnotation(Adaptive.class);
StringBuilder code = new StringBuilder(512);
if (adaptiveAnnotation == null) {
return generateUnsupported(method);
} else {
int urlTypeIndex = getUrlTypeIndex(method);
// found parameter in URL type
if (urlTypeIndex != -1) {
// Null Point check
code.append(generateUrlNullCheck(urlTypeIndex));
} else {
// did not find parameter in URL type
code.append(generateUrlAssignmentIndirectly(method));
}
String[] value = getMethodAdaptiveValue(adaptiveAnnotation);
boolean hasInvocation = hasInvocationArgument(method);
code.append(generateInvocationArgumentNullCheck(method));
code.append(generateExtNameAssignment(value, hasInvocation));
// check extName == null?
code.append(generateExtNameNullCheck(value));
code.append(generateScopeModelAssignment());
code.append(generateExtensionAssignment());
// return statement
code.append(generateReturnAndInvocation(method));
}
return code.toString();
}
/**
* generate code for variable extName null check
*/
private String generateExtNameNullCheck(String[] value) {
return String.format(CODE_EXT_NAME_NULL_CHECK, type.getName(), Arrays.toString(value));
}
/**
* generate extName assignment code
*/
private String generateExtNameAssignment(String[] value, boolean hasInvocation) {
// TODO: refactor it
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);
}
}
}
return String.format(CODE_EXT_NAME_ASSIGNMENT, getNameCode);
}
/**
* @return
*/
private String generateScopeModelAssignment() {
return String.format(CODE_SCOPE_MODEL_ASSIGNMENT, type.getName());
}
private String generateExtensionAssignment() {
return String.format(CODE_EXTENSION_ASSIGNMENT, type.getName(), type.getName());
}
/**
* generate method invocation statement and return it if necessary
*/
private String generateReturnAndInvocation(Method method) {
String returnStatement = method.getReturnType().equals(void.class) ? "" : "return ";
String args = IntStream.range(0, method.getParameters().length)
.mapToObj(i -> String.format(CODE_EXTENSION_METHOD_INVOKE_ARGUMENT, i))
.collect(Collectors.joining(", "));
return returnStatement + String.format("extension.%s(%s);\n", method.getName(), args);
}
/**
* test if method has argument of type <code>Invocation</code>
*/
private boolean hasInvocationArgument(Method method) {
Class<?>[] pts = method.getParameterTypes();
return Arrays.stream(pts).anyMatch(p -> CLASS_NAME_INVOCATION.equals(p.getName()));
}
/**
* generate code to test argument of type <code>Invocation</code> is null
*/
private String generateInvocationArgumentNullCheck(Method method) {
Class<?>[] pts = method.getParameterTypes();
return IntStream.range(0, pts.length).filter(i -> CLASS_NAME_INVOCATION.equals(pts[i].getName()))
.mapToObj(i -> String.format(CODE_INVOCATION_ARGUMENT_NULL_CHECK, i, i))
.findFirst().orElse("");
}
/**
* get value of adaptive annotation or if empty return splitted simple name
*/
private String[] getMethodAdaptiveValue(Adaptive adaptiveAnnotation) {
String[] value = adaptiveAnnotation.value();
// value is not set, use the value generated from class name as the key
if (value.length == 0) {
String splitName = StringUtils.camelToSplitName(type.getSimpleName(), ".");
value = new String[]{splitName};
}
return value;
}
/**
* get parameter with type <code>URL</code> from method parameter:
* <p>
* test if parameter has method which returns type <code>URL</code>
* <p>
* if not found, throws IllegalStateException
*/
private String generateUrlAssignmentIndirectly(Method method) {
Class<?>[] pts = method.getParameterTypes();
Map<String, Integer> getterReturnUrl = new HashMap<>();
// find URL getter method
for (int i = 0; i < pts.length; ++i) {
for (Method m : pts[i].getMethods()) {
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) {
getterReturnUrl.put(name, i);
}
}
}
if (getterReturnUrl.size() <= 0) {
// getter method not found, throw
throw new IllegalStateException("Failed to create adaptive class for interface " + type.getName()
+ ": not found url parameter or url attribute in parameters of method " + method.getName());
}
Integer index = getterReturnUrl.get("getUrl");
if (index != null) {
return generateGetUrlNullCheck(index, pts[index], "getUrl");
} else {
Map.Entry<String, Integer> entry = getterReturnUrl.entrySet().iterator().next();
return generateGetUrlNullCheck(entry.getValue(), pts[entry.getValue()], entry.getKey());
}
}
/**
* 1, test if argi is null
* 2, test if argi.getXX() returns null
* 3, assign url with argi.getXX()
*/
private String generateGetUrlNullCheck(int index, Class<?> type, String method) {
// Null point check
StringBuilder code = new StringBuilder();
code.append(String.format("if (arg%d == null) throw new IllegalArgumentException(\"%s argument == null\");\n",
index, type.getName()));
code.append(String.format("if (arg%d.%s() == null) throw new IllegalArgumentException(\"%s argument %s() == null\");\n",
index, method, type.getName(), method));
code.append(String.format("%s url = arg%d.%s();\n", URL.class.getName(), index, method));
return code.toString();
}
}
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