defaultxmlbeandefinitionparser.java

spring的源代码

		else {
			if (StringUtils.hasLength(typeAttr)) {
				cargs.addGenericArgumentValue(val, typeAttr);
			}
			else {
				cargs.addGenericArgumentValue(val);
			}
		}
	}

	/**
	 * Parse a property element.
	 */
	protected void parsePropertyElement(Element ele, String beanName, MutablePropertyValues pvs)
			throws BeanDefinitionStoreException {

		String propertyName = ele.getAttribute(NAME_ATTRIBUTE);
		if (!StringUtils.hasLength(propertyName)) {
			throw new BeanDefinitionStoreException(
					getResource(), beanName, "Tag 'property' must have a 'name' attribute");
		}
		if (pvs.contains(propertyName)) {
			throw new BeanDefinitionStoreException(
					getResource(), beanName, "Multiple 'property' definitions for property '" + propertyName + "'");
		}
		Object val = parsePropertyValue(ele, beanName, propertyName);
		pvs.addPropertyValue(propertyName, val);
	}


	/**
	 * Get the value of a property element. May be a list etc.
	 * Also used for constructor arguments, "propertyName" being null in this case.
	 */
	protected Object parsePropertyValue(Element ele, String beanName, String propertyName)
			throws BeanDefinitionStoreException {

		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++) {
			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.
					if (subElement != null) {
						throw new BeanDefinitionStoreException(
								getResource(), beanName, elementName + " must not contain more than one sub-element");
					}
					subElement = candidateEle;
				}
			}
		}

		boolean hasRefAttribute = ele.hasAttribute(REF_ATTRIBUTE);
		boolean hasValueAttribute = ele.hasAttribute(VALUE_ATTRIBUTE);
		if ((hasRefAttribute && hasValueAttribute) ||
				((hasRefAttribute || hasValueAttribute)) && subElement != null) {
			throw new BeanDefinitionStoreException(
					getResource(), beanName, elementName +
					" is only allowed to contain either 'ref' attribute OR 'value' attribute OR sub-element");
		}
		if (hasRefAttribute) {
			String refName = ele.getAttribute(REF_ATTRIBUTE);
			if (!StringUtils.hasText(refName)) {
				throw new BeanDefinitionStoreException(
						getResource(), beanName, elementName + " contains empty 'ref' attribute");
			}
			return new RuntimeBeanReference(refName);
		}
		else if (hasValueAttribute) {
			return ele.getAttribute(VALUE_ATTRIBUTE);
		}

		if (subElement == null) {
			// Neither child element nor "ref" or "value" attribute found.
			throw new BeanDefinitionStoreException(
					getResource(), beanName, elementName + " must specify a ref or value");
		}

		return parsePropertySubElement(subElement, beanName);
	}

	/**
	 * Parse a value, ref or collection sub-element of a property or
	 * constructor-arg element.
	 * @param ele subelement of property element; we don't know which yet
	 */
	protected Object parsePropertySubElement(Element ele, String beanName) throws BeanDefinitionStoreException {
		if (ele.getTagName().equals(BEAN_ELEMENT)) {
			try {
				return parseBeanDefinitionElement(ele, true);
			}
			catch (BeanDefinitionStoreException ex) {
				throw new BeanDefinitionStoreException(
						getResource(), beanName, "Could not parse inner bean definition", ex);
			}
		}
		else if (ele.getTagName().equals(REF_ELEMENT)) {
			// A generic reference to any name of any bean.
			String refName = ele.getAttribute(BEAN_REF_ATTRIBUTE);
			boolean toParent = false;
			if (!StringUtils.hasLength(refName)) {
				// A reference to the id of another bean in the same XML file.
				refName = ele.getAttribute(LOCAL_REF_ATTRIBUTE);
				if (!StringUtils.hasLength(refName)) {
					// A reference to the id of another bean in a parent context.
					refName = ele.getAttribute(PARENT_REF_ATTRIBUTE);
					toParent = true;
					if (!StringUtils.hasLength(refName)) {
						throw new BeanDefinitionStoreException(
								getResource(), beanName, "'bean', 'local' or 'parent' is required for <ref> element");
					}
				}
			}
			if (!StringUtils.hasText(refName)) {
				throw new BeanDefinitionStoreException(
						getResource(), beanName, "<ref> element contains empty target attribute");
			}
			return new RuntimeBeanReference(refName, toParent);
		}
		else if (ele.getTagName().equals(IDREF_ELEMENT)) {
			// A generic reference to any name of any bean.
			String beanRef = ele.getAttribute(BEAN_REF_ATTRIBUTE);
			if (!StringUtils.hasLength(beanRef)) {
				// A reference to the id of another bean in the same XML file.
				beanRef = ele.getAttribute(LOCAL_REF_ATTRIBUTE);
				if (!StringUtils.hasLength(beanRef)) {
					throw new BeanDefinitionStoreException(
							getResource(), beanName, "Either 'bean' or 'local' is required for <idref> element");
				}
			}
			return beanRef;
		}
		else if (ele.getTagName().equals(VALUE_ELEMENT)) {
			// It's a literal value.
			String value = DomUtils.getTextValue(ele);
			if (ele.hasAttribute(TYPE_ATTRIBUTE)) {
				String typeClassName = ele.getAttribute(TYPE_ATTRIBUTE);
				try {
					Class typeClass = ClassUtils.forName(typeClassName, this.beanDefinitionReader.getBeanClassLoader());
					return new TypedStringValue(value, typeClass);
				}
				catch (ClassNotFoundException ex) {
					throw new BeanDefinitionStoreException(
							getResource(), beanName, "Type class [" + typeClassName + "] not found for <value> element", ex);
				}
			}
			return value;
		}
		else if (ele.getTagName().equals(NULL_ELEMENT)) {
			// It's a distinguished null value.
			return null;
		}
		else if (ele.getTagName().equals(LIST_ELEMENT)) {
			return parseListElement(ele, beanName);
		}
		else if (ele.getTagName().equals(SET_ELEMENT)) {
			return parseSetElement(ele, beanName);
		}
		else if (ele.getTagName().equals(MAP_ELEMENT)) {
			return parseMapElement(ele, beanName);
		}
		else if (ele.getTagName().equals(PROPS_ELEMENT)) {
			return parsePropsElement(ele, beanName);
		}
		throw new BeanDefinitionStoreException(
				getResource(), beanName, "Unknown property sub-element: <" + ele.getTagName() + ">");
	}

	/**
	 * Parse a list element.
	 */
	protected List parseListElement(Element collectionEle, String beanName) throws BeanDefinitionStoreException {
		NodeList nl = collectionEle.getChildNodes();
		ManagedList list = new ManagedList(nl.getLength());
		for (int i = 0; i < nl.getLength(); i++) {
			if (nl.item(i) instanceof Element) {
				Element ele = (Element) nl.item(i);
				list.add(parsePropertySubElement(ele, beanName));
			}
		}
		return list;
	}

	/**
	 * Parse a set element.
	 */
	protected Set parseSetElement(Element collectionEle, String beanName) throws BeanDefinitionStoreException {
		NodeList nl = collectionEle.getChildNodes();
		ManagedSet set = new ManagedSet(nl.getLength());
		for (int i = 0; i < nl.getLength(); i++) {
			if (nl.item(i) instanceof Element) {
				Element ele = (Element) nl.item(i);
				set.add(parsePropertySubElement(ele, beanName));
			}
		}
		return set;
	}

	/**
	 * Parse a map element.
	 */
	protected Map parseMapElement(Element mapEle, String beanName) throws BeanDefinitionStoreException {
		List entryEles = DomUtils.getChildElementsByTagName(mapEle, ENTRY_ELEMENT);
		ManagedMap map = new ManagedMap(entryEles.size());

		for (Iterator it = entryEles.iterator(); it.hasNext();) {
			Element entryEle = (Element) it.next();
			// 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++) {
				if (entrySubNodes.item(j) instanceof Element) {
					Element candidateEle = (Element) entrySubNodes.item(j);
					if (candidateEle.getTagName().equals(KEY_ELEMENT)) {
						if (keyEle != null) {
							throw new BeanDefinitionStoreException(
									getResource(), beanName, "<entry> element is only allowed to contain one <key> sub-element");
						}
						keyEle = candidateEle;
					}
					else {
						// Child element is what we're looking for.
						if (valueEle != null) {
							throw new BeanDefinitionStoreException(
									getResource(), beanName, "<entry> element must not contain more than one value sub-element");
						}
						valueEle = candidateEle;
					}
				}
			}

			// Extract key from attribute or sub-element.
			Object key = null;
			boolean hasKeyAttribute = entryEle.hasAttribute(KEY_ATTRIBUTE);
			boolean hasKeyRefAttribute = entryEle.hasAttribute(KEY_REF_ATTRIBUTE);
			if ((hasKeyAttribute && hasKeyRefAttribute) ||
					((hasKeyAttribute || hasKeyRefAttribute)) && keyEle != null) {
				throw new BeanDefinitionStoreException(
						getResource(), beanName, "<entry> element is only allowed to contain either " +
						"a 'key' attribute OR a 'key-ref' attribute OR a <key> sub-element");
			}
			if (hasKeyAttribute) {
				key = entryEle.getAttribute(KEY_ATTRIBUTE);
			}
			else if (hasKeyRefAttribute) {
				String refName = entryEle.getAttribute(KEY_REF_ATTRIBUTE);
				if (!StringUtils.hasText(refName)) {
					throw new BeanDefinitionStoreException(
							getResource(), beanName, "<entry> element contains empty 'key-ref' attribute");
				}
				key = new RuntimeBeanReference(refName);
			}
			else if (keyEle != null) {
				key = parseKeyElement(keyEle, beanName);
			}
			else {
				throw new BeanDefinitionStoreException(
						getResource(), beanName, "<entry> element must specify a key");
			}

			// Extract value from attribute or sub-element.
			Object value = null;
			boolean hasValueAttribute = entryEle.hasAttribute(VALUE_ATTRIBUTE);
			boolean hasValueRefAttribute = entryEle.hasAttribute(VALUE_REF_ATTRIBUTE);
			if ((hasValueAttribute && hasValueRefAttribute) ||
					((hasValueAttribute || hasValueRefAttribute)) && valueEle != null) {
				throw new BeanDefinitionStoreException(
						getResource(), beanName, "<entry> element is only allowed to contain either " +
						"'value' attribute OR 'value-ref' attribute OR <value> sub-element");
			}
			if (hasValueAttribute) {
				value = entryEle.getAttribute(VALUE_ATTRIBUTE);
			}
			else if (hasValueRefAttribute) {
				String refName = entryEle.getAttribute(VALUE_REF_ATTRIBUTE);
				if (!StringUtils.hasText(refName)) {
					throw new BeanDefinitionStoreException(
							getResource(), beanName, "<entry> element contains empty 'value-ref' attribute");
				}
				value = new RuntimeBeanReference(refName);
			}
			else if (valueEle != null) {
				value = parsePropertySubElement(valueEle, beanName);
			}
			else {
				throw new BeanDefinitionStoreException(
						getResource(), beanName, "<entry> element must specify a value");
			}

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

		return map;
	}

	/**
	 * Parse a key sub-element of a map element.
	 */
	protected Object parseKeyElement(Element keyEle, String beanName) throws BeanDefinitionStoreException {
		NodeList nl = keyEle.getChildNodes();
		Element subElement = null;
		for (int i = 0; i < nl.getLength(); i++) {
			if (nl.item(i) instanceof Element) {
				Element candidateEle = (Element) nl.item(i);
				// Child element is what we're looking for.
				if (subElement != null) {
					throw new BeanDefinitionStoreException(
							getResource(), beanName, "<key> element must not contain more than one value sub-element");
				}
				subElement = candidateEle;
			}
		}
		return parsePropertySubElement(subElement, beanName);
	}

	/**
	 * Parse a props element.
	 */
	protected Properties parsePropsElement(Element propsEle, String beanName) throws BeanDefinitionStoreException {
		Properties props = new Properties();
		List propEles = DomUtils.getChildElementsByTagName(propsEle, PROP_ELEMENT);
		for (Iterator it = propEles.iterator(); it.hasNext();) {
			Element propEle = (Element) it.next();
			String key = propEle.getAttribute(KEY_ATTRIBUTE);
			// Trim the text value to avoid unwanted whitespace
			// caused by typical XML formatting.
			String value = DomUtils.getTextValue(propEle).trim();
			props.setProperty(key, value);
		}
		return props;
	}
}