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Spring BeanDefinitionParserDelegate

Author: HuiFer
源码阅读仓库: SourceHot-spring
全路径org.springframework.beans.factory.xml.BeanDefinitionParserDelegate
解析 xml 中标签的委托类
在这个类中定义常量如下，为后续解析提供帮助

	public static final String BEANS_NAMESPACE_URI = "http://www.springframework.org/schema/beans";

	public static final String MULTI_VALUE_ATTRIBUTE_DELIMITERS = ",; ";	

	public static final String TRUE_VALUE = "true";

	public static final String FALSE_VALUE = "false";

	public static final String DEFAULT_VALUE = "default";

	public static final String DESCRIPTION_ELEMENT = "description";

	public static final String AUTOWIRE_NO_VALUE = "no";

	public static final String AUTOWIRE_BY_NAME_VALUE = "byName";

	public static final String AUTOWIRE_BY_TYPE_VALUE = "byType";

	public static final String AUTOWIRE_CONSTRUCTOR_VALUE = "constructor";

	public static final String AUTOWIRE_AUTODETECT_VALUE = "autodetect";

	public static final String NAME_ATTRIBUTE = "name";

	public static final String BEAN_ELEMENT = "bean";

	public static final String META_ELEMENT = "meta";

	public static final String ID_ATTRIBUTE = "id";

	public static final String PARENT_ATTRIBUTE = "parent";

	public static final String CLASS_ATTRIBUTE = "class";

	public static final String ABSTRACT_ATTRIBUTE = "abstract";

	public static final String SCOPE_ATTRIBUTE = "scope";

	public static final String LAZY_INIT_ATTRIBUTE = "lazy-init";

	public static final String AUTOWIRE_ATTRIBUTE = "autowire";

	public static final String AUTOWIRE_CANDIDATE_ATTRIBUTE = "autowire-candidate";

	public static final String PRIMARY_ATTRIBUTE = "primary";

	public static final String DEPENDS_ON_ATTRIBUTE = "depends-on";

	public static final String INIT_METHOD_ATTRIBUTE = "init-method";

	public static final String DESTROY_METHOD_ATTRIBUTE = "destroy-method";

	public static final String FACTORY_METHOD_ATTRIBUTE = "factory-method";

	public static final String FACTORY_BEAN_ATTRIBUTE = "factory-bean";

	public static final String CONSTRUCTOR_ARG_ELEMENT = "constructor-arg";

	public static final String INDEX_ATTRIBUTE = "index";

	public static final String TYPE_ATTRIBUTE = "type";

	public static final String VALUE_TYPE_ATTRIBUTE = "value-type";

	public static final String KEY_TYPE_ATTRIBUTE = "key-type";

	public static final String PROPERTY_ELEMENT = "property";

	public static final String REF_ATTRIBUTE = "ref";

	public static final String VALUE_ATTRIBUTE = "value";

	public static final String LOOKUP_METHOD_ELEMENT = "lookup-method";

	public static final String REPLACED_METHOD_ELEMENT = "replaced-method";

	public static final String REPLACER_ATTRIBUTE = "replacer";

	public static final String ARG_TYPE_ELEMENT = "arg-type";

	public static final String ARG_TYPE_MATCH_ATTRIBUTE = "match";

	public static final String REF_ELEMENT = "ref";

	public static final String IDREF_ELEMENT = "idref";

	public static final String BEAN_REF_ATTRIBUTE = "bean";

	public static final String PARENT_REF_ATTRIBUTE = "parent";

	public static final String VALUE_ELEMENT = "value";

	public static final String NULL_ELEMENT = "null";

	public static final String ARRAY_ELEMENT = "array";

	public static final String LIST_ELEMENT = "list";

	public static final String SET_ELEMENT = "set";

	public static final String MAP_ELEMENT = "map";

	public static final String ENTRY_ELEMENT = "entry";

	public static final String KEY_ELEMENT = "key";

	public static final String KEY_ATTRIBUTE = "key";

	public static final String KEY_REF_ATTRIBUTE = "key-ref";

	public static final String VALUE_REF_ATTRIBUTE = "value-ref";

	public static final String PROPS_ELEMENT = "props";

	public static final String PROP_ELEMENT = "prop";

	public static final String MERGE_ATTRIBUTE = "merge";

	public static final String QUALIFIER_ELEMENT = "qualifier";

	public static final String QUALIFIER_ATTRIBUTE_ELEMENT = "attribute";

	public static final String DEFAULT_LAZY_INIT_ATTRIBUTE = "default-lazy-init";

	public static final String DEFAULT_MERGE_ATTRIBUTE = "default-merge";

	public static final String DEFAULT_AUTOWIRE_ATTRIBUTE = "default-autowire";

	public static final String DEFAULT_AUTOWIRE_CANDIDATES_ATTRIBUTE = "default-autowire-candidates";

	public static final String DEFAULT_INIT_METHOD_ATTRIBUTE = "default-init-method";

	public static final String DEFAULT_DESTROY_METHOD_ATTRIBUTE = "default-destroy-method";

	private static final String SINGLETON_ATTRIBUTE = "singleton";

populateDefaults

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#populateDefaults方法解析属性赋值给DocumentDefaultsDefinition对象
代码逻辑如下
1. 读取属性
2. 判断是否默认值
3. 判断是否存在属性
4. 赋值

protected void populateDefaults(DocumentDefaultsDefinition defaults, @Nullable DocumentDefaultsDefinition parentDefaults, Element root) {
   // 获取 default-lazy-init 属性值
   String lazyInit = root.getAttribute(DEFAULT_LAZY_INIT_ATTRIBUTE);
   // 判断是否是默认值
   if (isDefaultValue(lazyInit)) {
      // Potentially inherited from outer <beans> sections, otherwise falling back to false.
      lazyInit = (parentDefaults != null ? parentDefaults.getLazyInit() : FALSE_VALUE);
   }
   defaults.setLazyInit(lazyInit);

   String merge = root.getAttribute(DEFAULT_MERGE_ATTRIBUTE);
   if (isDefaultValue(merge)) {
      // Potentially inherited from outer <beans> sections, otherwise falling back to false.
      merge = (parentDefaults != null ? parentDefaults.getMerge() : FALSE_VALUE);
   }
   defaults.setMerge(merge);

   String autowire = root.getAttribute(DEFAULT_AUTOWIRE_ATTRIBUTE);
   if (isDefaultValue(autowire)) {
      // Potentially inherited from outer <beans> sections, otherwise falling back to 'no'.
      autowire = (parentDefaults != null ? parentDefaults.getAutowire() : AUTOWIRE_NO_VALUE);
   }
   defaults.setAutowire(autowire);

   if (root.hasAttribute(DEFAULT_AUTOWIRE_CANDIDATES_ATTRIBUTE)) {
      defaults.setAutowireCandidates(root.getAttribute(DEFAULT_AUTOWIRE_CANDIDATES_ATTRIBUTE));
   }
   else if (parentDefaults != null) {
      defaults.setAutowireCandidates(parentDefaults.getAutowireCandidates());
   }

   if (root.hasAttribute(DEFAULT_INIT_METHOD_ATTRIBUTE)) {
      defaults.setInitMethod(root.getAttribute(DEFAULT_INIT_METHOD_ATTRIBUTE));
   }
   else if (parentDefaults != null) {
      defaults.setInitMethod(parentDefaults.getInitMethod());
   }

   if (root.hasAttribute(DEFAULT_DESTROY_METHOD_ATTRIBUTE)) {
      defaults.setDestroyMethod(root.getAttribute(DEFAULT_DESTROY_METHOD_ATTRIBUTE));
   }
   else if (parentDefaults != null) {
      defaults.setDestroyMethod(parentDefaults.getDestroyMethod());
   }

   defaults.setSource(this.readerContext.extractSource(root));
}

DocumentDefaultsDefinition

全路径:org.springframework.beans.factory.xml.DocumentDefaultsDefinition
下面放出类的属性标记

public class DocumentDefaultsDefinition implements DefaultsDefinition {

   /**
    * true or false
    */
   @Nullable
   private String lazyInit;

   /**
    * true or false
    */
   @Nullable
   private String merge;

   /**
    * no or byName or byType
    */
   @Nullable
   private String autowire;

   /**
    * default-autowire-candidates 属性值
    */
   @Nullable
   private String autowireCandidates;

   /**
    * 实例化方法
    */
   @Nullable
   private String initMethod;

   /**
    * 摧毁方法
    */
   @Nullable
   private String destroyMethod;

   @Nullable
   private Object source;
}

checkNameUniqueness

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#checkNameUniqueness
判断 beanName 是否被使用, bean 别名是否被使用

/**
 * Validate that the specified bean name and aliases have not been used already
 * within the current level of beans element nesting.
 *
 * 判断 beanName 是否被使用, bean 别名是否被使用
 */
protected void checkNameUniqueness(String beanName, List<String> aliases, Element beanElement) {
   // 当前寻找的name
   String foundName = null;

   // 是否有 beanName
   // 使用过的name中是否存在
   if (StringUtils.hasText(beanName) && this.usedNames.contains(beanName)) {
      foundName = beanName;
   }
   if (foundName == null) {
      // 寻找匹配的第一个
      foundName = CollectionUtils.findFirstMatch(this.usedNames, aliases);
   }
   // 抛出异常
   if (foundName != null) {
      error("Bean name '" + foundName + "' is already used in this <beans> element", beanElement);
   }

   // 加入使用队列
   this.usedNames.add(beanName);
   this.usedNames.addAll(aliases);
}

createBeanDefinition

org.springframework.beans.factory.support.BeanDefinitionReaderUtils#createBeanDefinition
创建具有基本信息的BeanDefinition
1. parent bean name
2. bean clsss
3. bean class name

public static AbstractBeanDefinition createBeanDefinition(
      @Nullable String parentName, @Nullable String className, @Nullable ClassLoader classLoader) throws ClassNotFoundException {

   GenericBeanDefinition bd = new GenericBeanDefinition();
   // 设置 父bean
   bd.setParentName(parentName);
   if (className != null) {
      if (classLoader != null) {
         // 设置 class
         // 内部是通过反射创建 class
         bd.setBeanClass(ClassUtils.forName(className, classLoader));
      }
      else {
         // 设置 class name
         bd.setBeanClassName(className);
      }
   }
   return bd;
}

parseBeanDefinitionElement

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseBeanDefinitionElement(org.w3c.dom.Element, org.springframework.beans.factory.config.BeanDefinition)
该方法用来解析 <bean/> 标签信息

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseBeanDefinitionElement(org.w3c.dom.Element, java.lang.String, org.springframework.beans.factory.config.BeanDefinition)

@Nullable
public AbstractBeanDefinition parseBeanDefinitionElement(
      Element ele, String beanName, @Nullable BeanDefinition containingBean) {

   this.parseState.push(new BeanEntry(beanName));

   String className = null;
   // 是否包含属性 class
   if (ele.hasAttribute(CLASS_ATTRIBUTE)) {
      className = ele.getAttribute(CLASS_ATTRIBUTE).trim();
   }
   String parent = null;
   // 是否包含属性 parent
   if (ele.hasAttribute(PARENT_ATTRIBUTE)) {
      parent = ele.getAttribute(PARENT_ATTRIBUTE);
   }

   try {
      // 创建 bean definition
      AbstractBeanDefinition bd = createBeanDefinition(className, parent);

      // bean definition 属性设置
      parseBeanDefinitionAttributes(ele, beanName, containingBean, bd);
      bd.setDescription(DomUtils.getChildElementValueByTagName(ele, DESCRIPTION_ELEMENT));
      // 元信息设置
      parseMetaElements(ele, bd);
      // lookup-override 标签解析
      parseLookupOverrideSubElements(ele, bd.getMethodOverrides());
      // replaced-method sub-elements 标签解析
      parseReplacedMethodSubElements(ele, bd.getMethodOverrides());

      // constructor arg 标签解析
      parseConstructorArgElements(ele, bd);
      // property 标签解析
      parsePropertyElements(ele, bd);
      // qualifier 标签解析
      parseQualifierElements(ele, bd);
      // 资源设置
      bd.setResource(this.readerContext.getResource());
      // source 设置
      bd.setSource(extractSource(ele));

      return bd;
   }
   catch (ClassNotFoundException ex) {
      error("Bean class [" + className + "] not found", ele, ex);
   }
   catch (NoClassDefFoundError err) {
      error("Class that bean class [" + className + "] depends on not found", ele, err);
   }
   catch (Throwable ex) {
      error("Unexpected failure during bean definition parsing", ele, ex);
   }
   finally {
      this.parseState.pop();
   }

   return null;
}

parseBeanDefinitionAttributes

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseBeanDefinitionAttributes
将 xml 标签的数据读取到内存中设置给AbstractBeanDefinition

public AbstractBeanDefinition parseBeanDefinitionAttributes(Element ele, String beanName,
      @Nullable BeanDefinition containingBean, AbstractBeanDefinition bd) {

   // 是否存在 singleton 属性
   if (ele.hasAttribute(SINGLETON_ATTRIBUTE)) {
      error("Old 1.x 'singleton' attribute in use - upgrade to 'scope' declaration", ele);
   }
   // 是否存在 scope 属性
   else if (ele.hasAttribute(SCOPE_ATTRIBUTE)) {
      // 设置 scope 属性
      bd.setScope(ele.getAttribute(SCOPE_ATTRIBUTE));
   }
   // bean 定义是否为空
   else if (containingBean != null) {
      // Take default from containing bean in case of an inner bean definition.
      // 设置 bean definition 中的 scope
      bd.setScope(containingBean.getScope());
   }

   // 是否存在 abstract 属性
   if (ele.hasAttribute(ABSTRACT_ATTRIBUTE)) {
      // 设置 abstract 属性
      bd.setAbstract(TRUE_VALUE.equals(ele.getAttribute(ABSTRACT_ATTRIBUTE)));
   }

   // 获取 lazy-init 属性
   String lazyInit = ele.getAttribute(LAZY_INIT_ATTRIBUTE);
   // 是否是默认的 lazy-init 属性
   if (isDefaultValue(lazyInit)) {
      // 获取默认值
      lazyInit = this.defaults.getLazyInit();
   }
   // 设置 lazy-init 属性
   bd.setLazyInit(TRUE_VALUE.equals(lazyInit));

   // 获取注入方式
   String autowire = ele.getAttribute(AUTOWIRE_ATTRIBUTE);
   // 设置注入方式
   bd.setAutowireMode(getAutowireMode(autowire));

   // 依赖的bean
   if (ele.hasAttribute(DEPENDS_ON_ATTRIBUTE)) {
      String dependsOn = ele.getAttribute(DEPENDS_ON_ATTRIBUTE);
      bd.setDependsOn(StringUtils.tokenizeToStringArray(dependsOn, MULTI_VALUE_ATTRIBUTE_DELIMITERS));
   }

   // autowire-candidate 是否自动注入判断
   String autowireCandidate = ele.getAttribute(AUTOWIRE_CANDIDATE_ATTRIBUTE);
   if (isDefaultValue(autowireCandidate)) {
      String candidatePattern = this.defaults.getAutowireCandidates();
      if (candidatePattern != null) {
         String[] patterns = StringUtils.commaDelimitedListToStringArray(candidatePattern);
         // * 匹配 设置数据
         bd.setAutowireCandidate(PatternMatchUtils.simpleMatch(patterns, beanName));
      }
   }
   else {
      bd.setAutowireCandidate(TRUE_VALUE.equals(autowireCandidate));
   }

   // 获取 primary 书信
   if (ele.hasAttribute(PRIMARY_ATTRIBUTE)) {
      bd.setPrimary(TRUE_VALUE.equals(ele.getAttribute(PRIMARY_ATTRIBUTE)));
   }

   // 获取 init-method 属性
   if (ele.hasAttribute(INIT_METHOD_ATTRIBUTE)) {
      String initMethodName = ele.getAttribute(INIT_METHOD_ATTRIBUTE);
      bd.setInitMethodName(initMethodName);
   }
   // 没有 init-method 的情况处理
   else if (this.defaults.getInitMethod() != null) {
      bd.setInitMethodName(this.defaults.getInitMethod());
      bd.setEnforceInitMethod(false);
   }

   // 获取 destroy-method 属性
   if (ele.hasAttribute(DESTROY_METHOD_ATTRIBUTE)) {
      String destroyMethodName = ele.getAttribute(DESTROY_METHOD_ATTRIBUTE);
      bd.setDestroyMethodName(destroyMethodName);
   }
   // 没有 destroy-method 的情况处理
   else if (this.defaults.getDestroyMethod() != null) {
      bd.setDestroyMethodName(this.defaults.getDestroyMethod());
      bd.setEnforceDestroyMethod(false);
   }

   // 获取 factory-method 属性
   if (ele.hasAttribute(FACTORY_METHOD_ATTRIBUTE)) {
      bd.setFactoryMethodName(ele.getAttribute(FACTORY_METHOD_ATTRIBUTE));
   }
   // 获取 factory-bean 属性
   if (ele.hasAttribute(FACTORY_BEAN_ATTRIBUTE)) {
      bd.setFactoryBeanName(ele.getAttribute(FACTORY_BEAN_ATTRIBUTE));
   }

   return bd;
}

parseMetaElements

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseMetaElements
设置元数据.

标签meta的解析

public void parseMetaElements(Element ele, BeanMetadataAttributeAccessor attributeAccessor) {
   // 获取下级标签
   NodeList nl = ele.getChildNodes();
   // 循环子标签
   for (int i = 0; i < nl.getLength(); i++) {
      Node node = nl.item(i);
      // 设置数据
      if (isCandidateElement(node) && nodeNameEquals(node, META_ELEMENT)) {
         Element metaElement = (Element) node;
         // 获取 key 属性
         String key = metaElement.getAttribute(KEY_ATTRIBUTE);
         // 获取 value 属性
         String value = metaElement.getAttribute(VALUE_ATTRIBUTE);
         // 元数据对象设置
         BeanMetadataAttribute attribute = new BeanMetadataAttribute(key, value);
         // 设置 source
         attribute.setSource(extractSource(metaElement));
         // 信息添加
         attributeAccessor.addMetadataAttribute(attribute);
      }
   }
}

使用案例

	<bean id="apple" class="org.source.hot.spring.overview.ioc.bean.lookup.Apple">
		<meta key="meta-key" value="meta-value"/>
	</bean>

ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("META-INF/beans/spring-lookup-method.xml");

ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
BeanDefinition apple = beanFactory.getBeanDefinition("apple");
Object attribute = apple.getAttribute("meta-key");
System.out.println(attribute);

parseLookupOverrideSubElements

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseLookupOverrideSubElements
解析标签

lookup-method

public void parseLookupOverrideSubElements(Element beanEle, MethodOverrides overrides) {
   // 获取子标签
   NodeList nl = beanEle.getChildNodes();
   for (int i = 0; i < nl.getLength(); i++) {
      Node node = nl.item(i);
      // 是否有 lookup-method 属性
      if (isCandidateElement(node) && nodeNameEquals(node, LOOKUP_METHOD_ELEMENT)) {
         Element ele = (Element) node;
         // 获取 name 属性
         String methodName = ele.getAttribute(NAME_ATTRIBUTE);
         // 获取 bean 属性
         String beanRef = ele.getAttribute(BEAN_ELEMENT);
         // 创建 覆盖依赖
         LookupOverride override = new LookupOverride(methodName, beanRef);
         // 设置 source
         override.setSource(extractSource(ele));
         overrides.addOverride(override);
      }
   }
}

使用案例

<bean id="apple" class="org.source.hot.spring.overview.ioc.bean.lookup.Apple">
		<meta key="meta-key" value="meta-value"/>
	</bean>

	<bean id="shop" class="org.source.hot.spring.overview.ioc.bean.lookup.Shop">
		<lookup-method name="getFruits" bean="apple"/>
	</bean>

public class LookupMain {
   public static void main(String[] args) {
      ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("META-INF/beans/spring-lookup-method.xml");
      Shop shop = context.getBean("shop", Shop.class);
      System.out.println(shop.getFruits().getName());
   }
}

parseReplacedMethodSubElements

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseReplacedMethodSubElements
解析标签

replaced-method

public void parseReplacedMethodSubElements(Element beanEle, MethodOverrides overrides) {
   // 子节点获取
   NodeList nl = beanEle.getChildNodes();
   for (int i = 0; i < nl.getLength(); i++) {
      Node node = nl.item(i);
      // 是否包含 replaced-method 属性
      if (isCandidateElement(node) && nodeNameEquals(node, REPLACED_METHOD_ELEMENT)) {
         Element replacedMethodEle = (Element) node;
         // 获取 name 属性
         String name = replacedMethodEle.getAttribute(NAME_ATTRIBUTE);
         // 获取 replacer
         String callback = replacedMethodEle.getAttribute(REPLACER_ATTRIBUTE);
         // 对象组装
         ReplaceOverride replaceOverride = new ReplaceOverride(name, callback);
         // Look for arg-type match elements.
         // 子节点属性
         // 处理 arg-type 标签
         List<Element> argTypeEles = DomUtils.getChildElementsByTagName(replacedMethodEle, ARG_TYPE_ELEMENT);

         for (Element argTypeEle : argTypeEles) {
            // 获取 match 数据值
            String match = argTypeEle.getAttribute(ARG_TYPE_MATCH_ATTRIBUTE);
            // match 信息设置
            match = (StringUtils.hasText(match) ? match : DomUtils.getTextValue(argTypeEle));
            if (StringUtils.hasText(match)) {
               // 添加类型标识
               replaceOverride.addTypeIdentifier(match);
            }
         }
         // 设置 source
         replaceOverride.setSource(extractSource(replacedMethodEle));
         // 重载列表添加
         overrides.addOverride(replaceOverride);
      }
   }
}

使用案例

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xmlns="http://www.springframework.org/schema/beans"
      xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
   <bean id="apple" class="org.source.hot.spring.overview.ioc.bean.lookup.Apple">
      <replaced-method replacer="methodReplacerApple" name="hello" >
         <arg-type>String</arg-type>
      </replaced-method>

   </bean>

   <bean id="methodReplacerApple" class="org.source.hot.spring.overview.ioc.bean.lookup.MethodReplacerApple">

   </bean>

</beans>

public class MethodReplacerApple implements MethodReplacer {
   @Override
   public Object reimplement(Object obj, Method method, Object[] args) throws Throwable {
      System.out.println("方法替换");
      return obj;
   }
}

replacer需要使用MethodReplacer实现类

parseConstructorArgElements

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseConstructorArgElements
解析constructor-arg标签

public void parseConstructorArgElements(Element beanEle, BeanDefinition bd) {
   // 获取
   NodeList nl = beanEle.getChildNodes();
   for (int i = 0; i < nl.getLength(); i++) {
      Node node = nl.item(i);
      if (isCandidateElement(node) && nodeNameEquals(node, CONSTRUCTOR_ARG_ELEMENT)) {
         // 解析 constructor-arg 下级标签
         parseConstructorArgElement((Element) node, bd);
      }
   }
}

public void parseConstructorArgElement(Element ele, BeanDefinition bd) {
   // 获取 index 属性
   String indexAttr = ele.getAttribute(INDEX_ATTRIBUTE);
   // 获取 type 属性
   String typeAttr = ele.getAttribute(TYPE_ATTRIBUTE);
   // 获取 name 属性
   String nameAttr = ele.getAttribute(NAME_ATTRIBUTE);
   if (StringUtils.hasLength(indexAttr)) {
      try {
         // 构造参数的所以未知
         int index = Integer.parseInt(indexAttr);
         if (index < 0) {
            error("'index' cannot be lower than 0", ele);
         }
         else {
            try {
               this.parseState.push(new ConstructorArgumentEntry(index));
               // 解析 property 标签
               Object value = parsePropertyValue(ele, bd, null);
               // 创建 构造函数的 属性控制类
               ConstructorArgumentValues.ValueHolder valueHolder = new ConstructorArgumentValues.ValueHolder(value);
               if (StringUtils.hasLength(typeAttr)) {
                  // 类型设置
                  valueHolder.setType(typeAttr);
               }
               if (StringUtils.hasLength(nameAttr)) {
                  // 名称设置
                  valueHolder.setName(nameAttr);
               }
               // 源设置
               valueHolder.setSource(extractSource(ele));
               if (bd.getConstructorArgumentValues().hasIndexedArgumentValue(index)) {
                  error("Ambiguous constructor-arg entries for index " + index, ele);
               }
               else {
                  // 添加 构造函数信息
                  bd.getConstructorArgumentValues().addIndexedArgumentValue(index, valueHolder);
               }
            }
            finally {
               this.parseState.pop();
            }
         }
      }
      catch (NumberFormatException ex) {
         error("Attribute 'index' of tag 'constructor-arg' must be an integer", ele);
      }
   }
   else {
      try {
         this.parseState.push(new ConstructorArgumentEntry());
         // 解析 property 标签
         Object value = parsePropertyValue(ele, bd, null);
         // 创建 构造函数的 属性控制类
         ConstructorArgumentValues.ValueHolder valueHolder = new ConstructorArgumentValues.ValueHolder(value);
         if (StringUtils.hasLength(typeAttr)) {
            // 类型设置
            valueHolder.setType(typeAttr);
         }
         if (StringUtils.hasLength(nameAttr)) {
            // 名称设置
            valueHolder.setName(nameAttr);
         }
         // 源设置
         valueHolder.setSource(extractSource(ele));
         // 添加 构造函数信息
         bd.getConstructorArgumentValues().addGenericArgumentValue(valueHolder);
      }
      finally {
         this.parseState.pop();
      }
   }
}

parseConstructorArgElement

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseConstructorArgElement
解析 constructor-arg 下级标签

@Nullable
public Object parsePropertyValue(Element ele, BeanDefinition bd, @Nullable String propertyName) {
   String elementName = (propertyName != null ?
         "<property> element for property '" + propertyName + "'" :
         "<constructor-arg> element");

   // Should only have one child element: ref, value, list, etc.
   NodeList nl = ele.getChildNodes();
   Element subElement = null;
   for (int i = 0; i < nl.getLength(); i++) {
      Node node = nl.item(i);
      if (node instanceof Element && !nodeNameEquals(node, DESCRIPTION_ELEMENT) &&
            !nodeNameEquals(node, META_ELEMENT)) {
         // Child element is what we're looking for.
         if (subElement != null) {
            error(elementName + " must not contain more than one sub-element", ele);
         }
         else {
            subElement = (Element) node;
         }
      }
   }

   // ref 属性是否存在
   boolean hasRefAttribute = ele.hasAttribute(REF_ATTRIBUTE);
   // value 属性是否存在
   boolean hasValueAttribute = ele.hasAttribute(VALUE_ATTRIBUTE);
   if ((hasRefAttribute && hasValueAttribute) ||
         ((hasRefAttribute || hasValueAttribute) && subElement != null)) {
      error(elementName +
            " is only allowed to contain either 'ref' attribute OR 'value' attribute OR sub-element", ele);
   }

   if (hasRefAttribute) {
      // 获取 ref 属性值
      String refName = ele.getAttribute(REF_ATTRIBUTE);
      if (!StringUtils.hasText(refName)) {
         error(elementName + " contains empty 'ref' attribute", ele);
      }
      // 创建 连接对象
      RuntimeBeanReference ref = new RuntimeBeanReference(refName);

      ref.setSource(extractSource(ele));
      return ref;
   }
   else if (hasValueAttribute) {
      // 获取 value
      TypedStringValue valueHolder = new TypedStringValue(ele.getAttribute(VALUE_ATTRIBUTE));
      valueHolder.setSource(extractSource(ele));
      return valueHolder;
   }
   else if (subElement != null) {
      return parsePropertySubElement(subElement, bd);
   }
   else {
      // Neither child element nor "ref" or "value" attribute found.
      error(elementName + " must specify a ref or value", ele);
      return null;
   }
}

parsePropertySubElement

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parsePropertySubElement(org.w3c.dom.Element, org.springframework.beans.factory.config.BeanDefinition)

@Nullable
public Object parsePropertySubElement(Element ele, @Nullable BeanDefinition bd) {
   // 解析 property 下级标签
   return parsePropertySubElement(ele, bd, null);
}

parsePropertySubElement

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parsePropertySubElement(org.w3c.dom.Element, org.springframework.beans.factory.config.BeanDefinition, java.lang.String)

@Nullable
public Object parsePropertySubElement(Element ele, @Nullable BeanDefinition bd, @Nullable String defaultValueType) {
   if (!isDefaultNamespace(ele)) {
      // 嵌套分析
      return parseNestedCustomElement(ele, bd);
   }
   else if (nodeNameEquals(ele, BEAN_ELEMENT)) {
      // 解析 bean 标签
      BeanDefinitionHolder nestedBd = parseBeanDefinitionElement(ele, bd);
      if (nestedBd != null) {
         // 装饰 bean define
         nestedBd = decorateBeanDefinitionIfRequired(ele, nestedBd, bd);
      }
      return nestedBd;
   }
   // ref 名称判断
   else if (nodeNameEquals(ele, REF_ELEMENT)) {
      // A generic reference to any name of any bean.
      // 获取 ref 属性
      String refName = ele.getAttribute(BEAN_REF_ATTRIBUTE);
      boolean toParent = false;
      if (!StringUtils.hasLength(refName)) {
         // A reference to the id of another bean in a parent context.
         // 获取 parent 属性
         refName = ele.getAttribute(PARENT_REF_ATTRIBUTE);
         toParent = true;
         if (!StringUtils.hasLength(refName)) {
            error("'bean' or 'parent' is required for <ref> element", ele);
            return null;
         }
      }
      if (!StringUtils.hasText(refName)) {
         error("<ref> element contains empty target attribute", ele);
         return null;
      }
      // bean 连接对象创建
      RuntimeBeanReference ref = new RuntimeBeanReference(refName, toParent);
      ref.setSource(extractSource(ele));
      return ref;
   }
   else if (nodeNameEquals(ele, IDREF_ELEMENT)) {
      return parseIdRefElement(ele);
   }
   else if (nodeNameEquals(ele, VALUE_ELEMENT)) {
      return parseValueElement(ele, defaultValueType);
   }
   else if (nodeNameEquals(ele, NULL_ELEMENT)) {
      // It's a distinguished null value. Let's wrap it in a TypedStringValue
      // object in order to preserve the source location.
      TypedStringValue nullHolder = new TypedStringValue(null);
      nullHolder.setSource(extractSource(ele));
      return nullHolder;
   }
   else if (nodeNameEquals(ele, ARRAY_ELEMENT)) {
      return parseArrayElement(ele, bd);
   }
   else if (nodeNameEquals(ele, LIST_ELEMENT)) {
      return parseListElement(ele, bd);
   }
   else if (nodeNameEquals(ele, SET_ELEMENT)) {
      return parseSetElement(ele, bd);
   }
   else if (nodeNameEquals(ele, MAP_ELEMENT)) {
      return parseMapElement(ele, bd);
   }
   else if (nodeNameEquals(ele, PROPS_ELEMENT)) {
      return parsePropsElement(ele);
   }
   else {
      error("Unknown property sub-element: [" + ele.getNodeName() + "]", ele);
      return null;
   }
}

parseIdRefElement

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseIdRefElement

@Nullable
public Object parseIdRefElement(Element ele) {
   // A generic reference to any name of any bean.
   // 获取 bean 属性
   String refName = ele.getAttribute(BEAN_REF_ATTRIBUTE);
   if (!StringUtils.hasLength(refName)) {
      error("'bean' is required for <idref> element", ele);
      return null;
   }
   if (!StringUtils.hasText(refName)) {
      error("<idref> element contains empty target attribute", ele);
      return null;
   }
   // 设置 bean 链接对象
   RuntimeBeanNameReference ref = new RuntimeBeanNameReference(refName);
   // 设置原
   ref.setSource(extractSource(ele));
   return ref;
}

parseValueElement

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseValueElement

	public Object parseValueElement(Element ele, @Nullable String defaultTypeName) {
		// It's a literal value.
		// 获取 xml 中的文本变量
		String value = DomUtils.getTextValue(ele);
		// 获取 type 属性
		String specifiedTypeName = ele.getAttribute(TYPE_ATTRIBUTE);
		// 类型
		String typeName = specifiedTypeName;
		if (!StringUtils.hasText(typeName)) {
			typeName = defaultTypeName;
		}
		try {
			// 创建类型值
			TypedStringValue typedValue = buildTypedStringValue(value, typeName);
			typedValue.setSource(extractSource(ele));
			typedValue.setSpecifiedTypeName(specifiedTypeName);
			return typedValue;
		}
		catch (ClassNotFoundException ex) {
			error("Type class [" + typeName + "] not found for <value> element", ele, ex);
			return value;
		}
	}

buildTypedStringValue

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#buildTypedStringValue
构造对象, 没有创建对象

protected TypedStringValue buildTypedStringValue(String value, @Nullable String targetTypeName)
      throws ClassNotFoundException {
   // class loader 
   ClassLoader classLoader = this.readerContext.getBeanClassLoader();
   TypedStringValue typedValue;
   if (!StringUtils.hasText(targetTypeName)) {
      typedValue = new TypedStringValue(value);
   }
   else if (classLoader != null) {
      // 目标类
      Class<?> targetType = ClassUtils.forName(targetTypeName, classLoader);
      // 构造
      typedValue = new TypedStringValue(value, targetType);
   }
   else {
      // 构造
      typedValue = new TypedStringValue(value, targetTypeName);
   }
   return typedValue;
}

parseArrayElement

public Object parseArrayElement(Element arrayEle, @Nullable BeanDefinition bd) {
   // 获取 value-type 属性
   String elementType = arrayEle.getAttribute(VALUE_TYPE_ATTRIBUTE);
   // 子节点
   NodeList nl = arrayEle.getChildNodes();
   // 合并 array 的类
   ManagedArray target = new ManagedArray(elementType, nl.getLength());
   target.setSource(extractSource(arrayEle));
   target.setElementTypeName(elementType);
   target.setMergeEnabled(parseMergeAttribute(arrayEle));
   // 处理 collection 节点
   parseCollectionElements(nl, target, bd, elementType);
   return target;
}

parseListElement

public List<Object> parseListElement(Element collectionEle, @Nullable BeanDefinition bd) {
   String defaultElementType = collectionEle.getAttribute(VALUE_TYPE_ATTRIBUTE);
   NodeList nl = collectionEle.getChildNodes();
   ManagedList<Object> target = new ManagedList<>(nl.getLength());
   target.setSource(extractSource(collectionEle));
   target.setElementTypeName(defaultElementType);
   target.setMergeEnabled(parseMergeAttribute(collectionEle));
   parseCollectionElements(nl, target, bd, defaultElementType);
   return target;
}

parseSetElement

public Set<Object> parseSetElement(Element collectionEle, @Nullable BeanDefinition bd) {
   String defaultElementType = collectionEle.getAttribute(VALUE_TYPE_ATTRIBUTE);
   NodeList nl = collectionEle.getChildNodes();
   ManagedSet<Object> target = new ManagedSet<>(nl.getLength());
   target.setSource(extractSource(collectionEle));
   target.setElementTypeName(defaultElementType);
   target.setMergeEnabled(parseMergeAttribute(collectionEle));
   parseCollectionElements(nl, target, bd, defaultElementType);
   return target;
}

parseCollectionElements

parseArrayElement、parseListElement、parseSetElement 都围绕者下面这个方法进行数据合并

protected void parseCollectionElements(
      NodeList elementNodes, Collection<Object> target, @Nullable BeanDefinition bd, String defaultElementType) {

   for (int i = 0; i < elementNodes.getLength(); i++) {
      Node node = elementNodes.item(i);
      if (node instanceof Element && !nodeNameEquals(node, DESCRIPTION_ELEMENT)) {
         // 处理子节点
         target.add(parsePropertySubElement((Element) node, bd, defaultElementType));
      }
   }
}

parseMapElement

public Map<Object, Object> parseMapElement(Element mapEle, @Nullable BeanDefinition bd) {
   // key-type 属性获取
   String defaultKeyType = mapEle.getAttribute(KEY_TYPE_ATTRIBUTE);
   // value-type 属性互殴去
   String defaultValueType = mapEle.getAttribute(VALUE_TYPE_ATTRIBUTE);

   // entry 标签获取
   List<Element> entryEles = DomUtils.getChildElementsByTagName(mapEle, ENTRY_ELEMENT);
   // 合并 map 对象
   ManagedMap<Object, Object> map = new ManagedMap<>(entryEles.size());
   map.setSource(extractSource(mapEle));
   map.setKeyTypeName(defaultKeyType);
   map.setValueTypeName(defaultValueType);
   map.setMergeEnabled(parseMergeAttribute(mapEle));

   // 循环 entry 节点
   for (Element entryEle : entryEles) {
      // Should only have one value child element: ref, value, list, etc.
      // Optionally, there might be a key child element.
      NodeList entrySubNodes = entryEle.getChildNodes();
      Element keyEle = null;
      Element valueEle = null;
      for (int j = 0; j < entrySubNodes.getLength(); j++) {
         Node node = entrySubNodes.item(j);
         if (node instanceof Element) {
            Element candidateEle = (Element) node;
            // 节点名称是否为 key
            if (nodeNameEquals(candidateEle, KEY_ELEMENT)) {
               if (keyEle != null) {
                  error("<entry> element is only allowed to contain one <key> sub-element", entryEle);
               }
               else {
                  keyEle = candidateEle;
               }
            }
            else {
               // Child element is what we're looking for.
               if (nodeNameEquals(candidateEle, DESCRIPTION_ELEMENT)) {
                  // the element is a <description> -> ignore it
               }
               else if (valueEle != null) {
                  error("<entry> element must not contain more than one value sub-element", entryEle);
               }
               else {
                  valueEle = candidateEle;
               }
            }
         }
      }

      // Extract key from attribute or sub-element.
      Object key = null;
      // key 属性
      boolean hasKeyAttribute = entryEle.hasAttribute(KEY_ATTRIBUTE);
      // key-ref 属性
      boolean hasKeyRefAttribute = entryEle.hasAttribute(KEY_REF_ATTRIBUTE);
      if ((hasKeyAttribute && hasKeyRefAttribute) ||
            (hasKeyAttribute || hasKeyRefAttribute) && keyEle != null) {
         error("<entry> element is only allowed to contain either " +
               "a 'key' attribute OR a 'key-ref' attribute OR a <key> sub-element", entryEle);
      }
      if (hasKeyAttribute) {
         // TypedStringValue 构建
         key = buildTypedStringValueForMap(entryEle.getAttribute(KEY_ATTRIBUTE), defaultKeyType, entryEle);
      }
      else if (hasKeyRefAttribute) {
         // key-ref 属性获取
         String refName = entryEle.getAttribute(KEY_REF_ATTRIBUTE);
         if (!StringUtils.hasText(refName)) {
            error("<entry> element contains empty 'key-ref' attribute", entryEle);
         }
         // 创建 bean 连接对象
         RuntimeBeanReference ref = new RuntimeBeanReference(refName);
         ref.setSource(extractSource(entryEle));
         key = ref;
      }
      else if (keyEle != null) {
         // 获取 key 数据
         key = parseKeyElement(keyEle, bd, defaultKeyType);
      }
      else {
         error("<entry> element must specify a key", entryEle);
      }

      // Extract value from attribute or sub-element.
      Object value = null;
      // value 属性是否存在
      boolean hasValueAttribute = entryEle.hasAttribute(VALUE_ATTRIBUTE);
      // value-ref 属性是否存在
      boolean hasValueRefAttribute = entryEle.hasAttribute(VALUE_REF_ATTRIBUTE);
      // 是否存在 value-type 属性
      boolean hasValueTypeAttribute = entryEle.hasAttribute(VALUE_TYPE_ATTRIBUTE);
      if ((hasValueAttribute && hasValueRefAttribute) ||
            (hasValueAttribute || hasValueRefAttribute) && valueEle != null) {
         error("<entry> element is only allowed to contain either " +
               "'value' attribute OR 'value-ref' attribute OR <value> sub-element", entryEle);
      }
      if ((hasValueTypeAttribute && hasValueRefAttribute) ||
            (hasValueTypeAttribute && !hasValueAttribute) ||
            (hasValueTypeAttribute && valueEle != null)) {
         error("<entry> element is only allowed to contain a 'value-type' " +
               "attribute when it has a 'value' attribute", entryEle);
      }
      if (hasValueAttribute) {
         // 获取 value-type 属性
         String valueType = entryEle.getAttribute(VALUE_TYPE_ATTRIBUTE);
         if (!StringUtils.hasText(valueType)) {
            // 设置默认value-type
            valueType = defaultValueType;
         }
         // 创建 TypedStringValue
         value = buildTypedStringValueForMap(entryEle.getAttribute(VALUE_ATTRIBUTE), valueType, entryEle);
      }
      else if (hasValueRefAttribute) {
         // 获取 value-ref 属性
         String refName = entryEle.getAttribute(VALUE_REF_ATTRIBUTE);
         if (!StringUtils.hasText(refName)) {
            error("<entry> element contains empty 'value-ref' attribute", entryEle);
         }
         // 创建 bean 链接对象
         RuntimeBeanReference ref = new RuntimeBeanReference(refName);
         ref.setSource(extractSource(entryEle));
         value = ref;
      }
      else if (valueEle != null) {
         value = parsePropertySubElement(valueEle, bd, defaultValueType);
      }
      else {
         error("<entry> element must specify a value", entryEle);
      }

      // Add final key and value to the Map.
      map.put(key, value);
   }

   return map;
}

parsePropsElement

parsePropertyElement

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parsePropertyElement

public void parsePropertyElement(Element ele, BeanDefinition bd) {
   String propertyName = ele.getAttribute(NAME_ATTRIBUTE);
   if (!StringUtils.hasLength(propertyName)) {
      error("Tag 'property' must have a 'name' attribute", ele);
      return;
   }
   this.parseState.push(new PropertyEntry(propertyName));
   try {
      if (bd.getPropertyValues().contains(propertyName)) {
         error("Multiple 'property' definitions for property '" + propertyName + "'", ele);
         return;
      }
      // 解析 property 标签
      Object val = parsePropertyValue(ele, bd, propertyName);
      // 构造 PropertyValue 对象
      PropertyValue pv = new PropertyValue(propertyName, val);
      // 解析元信息
      parseMetaElements(ele, pv);
      pv.setSource(extractSource(ele));
      // 添加 pv 结构
      bd.getPropertyValues().addPropertyValue(pv);
   }
   finally {
      this.parseState.pop();
   }
}

parseQualifierElements

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseQualifierElements
解析 qualifier 标签和下级标签

public void parseQualifierElements(Element beanEle, AbstractBeanDefinition bd) {
   NodeList nl = beanEle.getChildNodes();
   for (int i = 0; i < nl.getLength(); i++) {
      Node node = nl.item(i);
      if (isCandidateElement(node) && nodeNameEquals(node, QUALIFIER_ELEMENT)) {
         // 单个解析
         parseQualifierElement((Element) node, bd);
      }
   }
}

parseQualifierElement

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseQualifierElement

public void parseQualifierElement(Element ele, AbstractBeanDefinition bd) {
   // 获取 type 属性
   String typeName = ele.getAttribute(TYPE_ATTRIBUTE);
   if (!StringUtils.hasLength(typeName)) {
      error("Tag 'qualifier' must have a 'type' attribute", ele);
      return;
   }
   this.parseState.push(new QualifierEntry(typeName));
   try {
      // 自动注入对象创建
      AutowireCandidateQualifier qualifier = new AutowireCandidateQualifier(typeName);
      // 设置源
      qualifier.setSource(extractSource(ele));
      // 获取 value 属性
      String value = ele.getAttribute(VALUE_ATTRIBUTE);
      if (StringUtils.hasLength(value)) {
         // 设置 属性 value , value
         qualifier.setAttribute(AutowireCandidateQualifier.VALUE_KEY, value);
      }
      NodeList nl = ele.getChildNodes();
      for (int i = 0; i < nl.getLength(); i++) {
         Node node = nl.item(i);
         if (isCandidateElement(node) && nodeNameEquals(node, QUALIFIER_ATTRIBUTE_ELEMENT)) {
            Element attributeEle = (Element) node;
            // 获取 key 属性
            String attributeName = attributeEle.getAttribute(KEY_ATTRIBUTE);
            // 获取 value 属性
            String attributeValue = attributeEle.getAttribute(VALUE_ATTRIBUTE);
            if (StringUtils.hasLength(attributeName) && StringUtils.hasLength(attributeValue)) {
               // key value 属性映射
               BeanMetadataAttribute attribute = new BeanMetadataAttribute(attributeName, attributeValue);
               attribute.setSource(extractSource(attributeEle));
               // 添加 qualifier 属性值
               qualifier.addMetadataAttribute(attribute);
            }
            else {
               error("Qualifier 'attribute' tag must have a 'name' and 'value'", attributeEle);
               return;
            }
         }
      }
      // 添加 qualifier
      bd.addQualifier(qualifier);
   }
   finally {
      this.parseState.pop();
   }
}

44 KiB Raw Blame History

Spring BeanDefinitionParserDelegate

populateDefaults

DocumentDefaultsDefinition

checkNameUniqueness

createBeanDefinition

parseBeanDefinitionElement

parseBeanDefinitionAttributes

parseMetaElements

parseLookupOverrideSubElements

parseReplacedMethodSubElements

parseConstructorArgElements

parseConstructorArgElement

parsePropertySubElement

parsePropertySubElement

parseIdRefElement

parseValueElement

buildTypedStringValue

parseArrayElement

parseListElement

parseSetElement

parseCollectionElements

parseMapElement

parsePropsElement

parsePropertyElement

parseQualifierElements

parseQualifierElement

44 KiB

Raw Blame History