defaultxmlbeandefinitionparser.java

spring的源代码

		catch (ClassNotFoundException ex) {
			throw new BeanDefinitionStoreException(this.resource, beanName,
																						 "Bean class [" + className + "] not found", ex);
		}
		catch (NoClassDefFoundError err) {
			throw new BeanDefinitionStoreException(this.resource, beanName,
																						 "Class that bean class [" + className + "] depends on not found", err);
		}
	}

	/**
	 * Parse constructor argument subelements of the given bean element.
	 */
	protected ConstructorArgumentValues getConstructorArgSubElements(String beanName, Element beanEle)
			throws ClassNotFoundException {
		NodeList nl = beanEle.getChildNodes();
		ConstructorArgumentValues cargs = new ConstructorArgumentValues();
		for (int i = 0; i < nl.getLength(); i++) {
			Node node = nl.item(i);
			if (node instanceof Element && CONSTRUCTOR_ARG_ELEMENT.equals(node.getNodeName())) {
				parseConstructorArgElement(beanName, cargs, (Element) node);
			}
		}
		return cargs;
	}

	/**
	 * Parse property value subelements of the given bean element.
	 */
	protected MutablePropertyValues getPropertyValueSubElements(String beanName, Element beanEle) {
		NodeList nl = beanEle.getChildNodes();
		MutablePropertyValues pvs = new MutablePropertyValues();
		for (int i = 0; i < nl.getLength(); i++) {
			Node node = nl.item(i);
			if (node instanceof Element && PROPERTY_ELEMENT.equals(node.getNodeName())) {
				parsePropertyElement(beanName, pvs, (Element) node);
			}
		}
		return pvs;
	}

	/**
	 * Parse a constructor-arg element.
	 */
	protected void parseConstructorArgElement(String beanName, ConstructorArgumentValues cargs, Element ele)
			throws DOMException, ClassNotFoundException {
		Object val = getPropertyValue(ele, beanName);
		String indexAttr = ele.getAttribute(INDEX_ATTRIBUTE);
		String typeAttr = ele.getAttribute(TYPE_ATTRIBUTE);
		if (!"".equals(indexAttr)) {
			try {
				int index = Integer.parseInt(indexAttr);
				if (index < 0) {
					throw new BeanDefinitionStoreException(this.resource, beanName, "'index' cannot be lower than 0");
				}
				if (!"".equals(typeAttr)) {
					cargs.addIndexedArgumentValue(index, val, typeAttr);
				}
				else {
					cargs.addIndexedArgumentValue(index, val);
				}
			}
			catch (NumberFormatException ex) {
				throw new BeanDefinitionStoreException(this.resource, beanName,
																							 "Attribute 'index' of tag 'constructor-arg' must be an integer");
			}
		}
		else {
			if (!"".equals(typeAttr)) {
				cargs.addGenericArgumentValue(val, typeAttr);
			}
			else {
				cargs.addGenericArgumentValue(val);
			}
		}
	}

	/**
	 * Parse a property element.
	 */
	protected void parsePropertyElement(String beanName, MutablePropertyValues pvs, Element ele)
			throws DOMException {
		String propertyName = ele.getAttribute(NAME_ATTRIBUTE);
		if ("".equals(propertyName)) {
			throw new BeanDefinitionStoreException(this.resource, beanName,
																						 "Tag 'property' must have a 'name' attribute");
		}
		Object val = getPropertyValue(ele, beanName);
		pvs.addPropertyValue(new PropertyValue(propertyName, val));
	}

	/**
	 * Get the value of a property element. May be a list.
	 * @param ele property element
	 */
	protected Object getPropertyValue(Element ele, String beanName) {
		// should only have one element child: value, ref, collection
		NodeList nl = ele.getChildNodes();
		Element valueRefOrCollectionElement = null;
		for (int i = 0; i < nl.getLength(); i++) {
			if (nl.item(i) instanceof Element) {
				Element candidateEle = (Element) nl.item(i);
				if (DESCRIPTION_ELEMENT.equals(candidateEle.getTagName())) {
					// keep going: we don't use this value for now
				}
				else {
					// child element is what we're looking for
					valueRefOrCollectionElement = candidateEle;
				}
			}
		}
		if (valueRefOrCollectionElement == null) {
			throw new BeanDefinitionStoreException(this.resource, beanName,
																						 "<property> element must have a subelement like 'value' or 'ref'");
		}
		return parsePropertySubelement(valueRefOrCollectionElement, beanName);
	}

	/**
	 * Parse a value, ref or collection subelement of a property element
	 * @param ele subelement of property element; we don't know which yet
	 */
	protected Object parsePropertySubelement(Element ele, String beanName) {
		if (ele.getTagName().equals(BEAN_ELEMENT)) {
			return parseBeanDefinition(ele, "(inner bean definition)");
		}
		else if (ele.getTagName().equals(REF_ELEMENT)) {
			// a generic reference to any name of any bean
			String beanRef = ele.getAttribute(BEAN_REF_ATTRIBUTE);
			if ("".equals(beanRef)) {
				// a reference to the id of another bean in the same XML file
				beanRef = ele.getAttribute(LOCAL_REF_ATTRIBUTE);
				if ("".equals(beanRef)) {
					throw new BeanDefinitionStoreException(this.resource, beanName,
																								 "Either 'bean' or 'local' is required for a reference");
				}
			}
			return new RuntimeBeanReference(beanRef);
		}
		else if (ele.getTagName().equals(IDREF_ELEMENT)) {
			// a generic reference to any name of any bean
			String beanRef = ele.getAttribute(BEAN_REF_ATTRIBUTE);
			if ("".equals(beanRef)) {
				// a reference to the id of another bean in the same XML file
				beanRef = ele.getAttribute(LOCAL_REF_ATTRIBUTE);
				if ("".equals(beanRef)) {
					throw new BeanDefinitionStoreException(this.resource, beanName,
																								 "Either 'bean' or 'local' is required for an idref");
				}
			}
			return beanRef;
		}
		else if (ele.getTagName().equals(LIST_ELEMENT)) {
			return getList(ele, beanName);
		}
		else if (ele.getTagName().equals(SET_ELEMENT)) {
			return getSet(ele, beanName);
		}
		else if (ele.getTagName().equals(MAP_ELEMENT)) {
			return getMap(ele, beanName);
		}
		else if (ele.getTagName().equals(PROPS_ELEMENT)) {
			return getProps(ele, beanName);
		}
		else if (ele.getTagName().equals(VALUE_ELEMENT)) {
			// it's a literal value
			return getTextValue(ele, beanName);
		}
		else if (ele.getTagName().equals(NULL_ELEMENT)) {
			// it's a distinguished null value
			return null;
		}
		throw new BeanDefinitionStoreException(this.resource, beanName,
																					 "Unknown subelement of <property>: <" + ele.getTagName() + ">");
	}

	protected List getList(Element collectionEle, String beanName) {
		NodeList nl = collectionEle.getChildNodes();
		ManagedList l = new ManagedList();
		for (int i = 0; i < nl.getLength(); i++) {
			if (nl.item(i) instanceof Element) {
				Element ele = (Element) nl.item(i);
				l.add(parsePropertySubelement(ele, beanName));
			}
		}
		return l;
	}

	protected Set getSet(Element collectionEle, String beanName) {
		NodeList nl = collectionEle.getChildNodes();
		ManagedSet s = new ManagedSet();
		for (int i = 0; i < nl.getLength(); i++) {
			if (nl.item(i) instanceof Element) {
				Element ele = (Element) nl.item(i);
				s.add(parsePropertySubelement(ele, beanName));
			}
		}
		return s;
	}

	protected Map getMap(Element mapEle, String beanName) {
		ManagedMap m = new ManagedMap();
		List l = getChildElementsByTagName(mapEle, ENTRY_ELEMENT);
		for (int i = 0; i < l.size(); i++) {
			Element entryEle = (Element) l.get(i);
			String key = entryEle.getAttribute(KEY_ATTRIBUTE);
			// TODO hack: make more robust
			NodeList subEles = entryEle.getElementsByTagName("*");
			m.put(key, parsePropertySubelement((Element) subEles.item(0), beanName));
		}
		return m;
	}

	/**
	 * Don't use the horrible DOM API to get child elements:
	 * Get an element's children with a given element name
	 */
	protected List getChildElementsByTagName(Element mapEle, String elementName) {
		NodeList nl = mapEle.getChildNodes();
		List nodes = new ArrayList();
		for (int i = 0; i < nl.getLength(); i++) {
			Node n = nl.item(i);
			if (n instanceof Element && elementName.equals(n.getNodeName())) {
				nodes.add(n);
			}
		}
		return nodes;
	}

	protected Properties getProps(Element propsEle, String beanName) {
		Properties props = new Properties();
		NodeList nl = propsEle.getElementsByTagName(PROP_ELEMENT);
		for (int i = 0; i < nl.getLength(); i++) {
			Element propEle = (Element) nl.item(i);
			String key = propEle.getAttribute(KEY_ATTRIBUTE);
			// trim the text value to avoid unwanted whitespace
			// caused by typical XML formatting
			String value = getTextValue(propEle, beanName).trim();
			props.setProperty(key, value);
		}
		return props;
	}

	/**
	 * Make the horrible DOM API slightly more bearable:
	 * get the text value we know this element contains
	 */
	protected String getTextValue(Element ele, String beanName) {
		NodeList nl = ele.getChildNodes();
		if (nl.item(0) == null) {
			// treat empty value as empty String
			return "";
		}
		if (nl.getLength() != 1 || !(nl.item(0) instanceof Text)) {
			throw new BeanDefinitionStoreException(this.resource, beanName,
																						 "Unexpected element or type mismatch: expected single node of " +
																						 nl.item(0).getClass() + " to be of type Text: " + "found " + ele, null);
		}
		Text t = (Text) nl.item(0);
		// This will be a String
		return t.getData();
	}

	protected int getDependencyCheck(String att) {
		int dependencyCheckCode = RootBeanDefinition.DEPENDENCY_CHECK_NONE;
		if (DEPENDENCY_CHECK_ALL_ATTRIBUTE_VALUE.equals(att)) {
			dependencyCheckCode = RootBeanDefinition.DEPENDENCY_CHECK_ALL;
		}
		else if (DEPENDENCY_CHECK_SIMPLE_ATTRIBUTE_VALUE.equals(att)) {
			dependencyCheckCode = RootBeanDefinition.DEPENDENCY_CHECK_SIMPLE;
		}
		else if (DEPENDENCY_CHECK_OBJECTS_ATTRIBUTE_VALUE.equals(att)) {
			dependencyCheckCode = RootBeanDefinition.DEPENDENCY_CHECK_OBJECTS;
		}
		// else leave default value
		return dependencyCheckCode;
	}

	protected int getAutowireMode(String att) {
		int autowire = RootBeanDefinition.AUTOWIRE_NO;
		if (AUTOWIRE_BY_NAME_VALUE.equals(att)) {
			autowire = RootBeanDefinition.AUTOWIRE_BY_NAME;
		}
		else if (AUTOWIRE_BY_TYPE_VALUE.equals(att)) {
			autowire = RootBeanDefinition.AUTOWIRE_BY_TYPE;
		}
		else if (AUTOWIRE_CONSTRUCTOR_VALUE.equals(att)) {
			autowire = RootBeanDefinition.AUTOWIRE_CONSTRUCTOR;
		}
		else if (AUTOWIRE_AUTODETECT_VALUE.equals(att)) {
			autowire = RootBeanDefinition.AUTOWIRE_AUTODETECT;
		}
		// else leave default value
		return autowire;
	}

}