beandefinitionparserdelegate.java

spring api 源代码

		else if (DomUtils.nodeNameEquals(ele, 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)) {
						error("'bean', 'local' or 'parent' is required for <ref> element", ele);
						return null;
					}
				}
			}
			if (!StringUtils.hasText(refName)) {
				error("<ref> element contains empty target attribute", ele);
				return null;
			}
			RuntimeBeanReference ref = new RuntimeBeanReference(refName, toParent);
			ref.setSource(extractSource(ele));
			return ref;
		}
		else if (DomUtils.nodeNameEquals(ele, IDREF_ELEMENT)) {
			// A generic reference to any name of any bean.
			String refName = ele.getAttribute(BEAN_REF_ATTRIBUTE);
			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)) {
					error("Either 'bean' or 'local' is required for <idref> element", ele);
					return null;
				}
			}
			if (!StringUtils.hasText(refName)) {
				error("<idref> element contains empty target attribute", ele);
				return null;
			}
			RuntimeBeanNameReference ref = new RuntimeBeanNameReference(refName);
			ref.setSource(extractSource(ele));
			return ref;
		}
		else if (DomUtils.nodeNameEquals(ele, VALUE_ELEMENT)) {
			// It's a literal value.
			String value = DomUtils.getTextValue(ele);
			String typeClassName = ele.getAttribute(TYPE_ATTRIBUTE);
			if (!StringUtils.hasText(typeClassName)) {
				typeClassName = defaultTypeClassName;
			}
			try {
				return buildTypedStringValue(value, typeClassName, ele);
			}
			catch (ClassNotFoundException ex) {
				error("Type class [" + typeClassName + "] not found for <value> element", ele, ex);
				return value;
			}
		}
		else if (DomUtils.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 (DomUtils.nodeNameEquals(ele, LIST_ELEMENT)) {
			return parseListElement(ele, bd);
		}
		else if (DomUtils.nodeNameEquals(ele, SET_ELEMENT)) {
			return parseSetElement(ele, bd);
		}
		else if (DomUtils.nodeNameEquals(ele, MAP_ELEMENT)) {
			return parseMapElement(ele, bd);
		}
		else if (DomUtils.nodeNameEquals(ele, PROPS_ELEMENT)) {
			return parsePropsElement(ele);
		}
		error("Unknown property sub-element: [" + ele.getNodeName() + "]", ele);
		return null;
	}

	/**
	 * Build a typed String value Object for the given raw value.
	 * @see org.springframework.beans.factory.config.TypedStringValue
	 */
	protected Object buildTypedStringValue(String value, String targetTypeName, Element ele)
			throws ClassNotFoundException {

		ClassLoader classLoader = this.readerContext.getBeanClassLoader();
		TypedStringValue typedValue = null;
		if (!StringUtils.hasText(targetTypeName)) {
			typedValue = new TypedStringValue(value);
		}
		else if (classLoader != null) {
			Class targetType = ClassUtils.forName(targetTypeName, classLoader);
			typedValue = new TypedStringValue(value, targetType);
		}
		else {
			typedValue = new TypedStringValue(value, targetTypeName);
		}
		typedValue.setSource(extractSource(ele));
		return typedValue;
	}

	/**
	 * Parse a list element.
	 */
	public List parseListElement(Element collectionEle, BeanDefinition bd) {
		String defaultTypeClassName = collectionEle.getAttribute(VALUE_TYPE_ATTRIBUTE);
		NodeList nl = collectionEle.getChildNodes();
		ManagedList list = new ManagedList(nl.getLength());
		list.setSource(extractSource(collectionEle));
		list.setMergeEnabled(parseMergeAttribute(collectionEle));
		for (int i = 0; i < nl.getLength(); i++) {
			if (nl.item(i) instanceof Element) {
				Element ele = (Element) nl.item(i);
				list.add(parsePropertySubElement(ele, bd, defaultTypeClassName));
			}
		}
		return list;
	}

	/**
	 * Parse a set element.
	 */
	public Set parseSetElement(Element collectionEle, BeanDefinition bd) {
		String defaultTypeClassName = collectionEle.getAttribute(VALUE_TYPE_ATTRIBUTE);
		NodeList nl = collectionEle.getChildNodes();
		ManagedSet set = new ManagedSet(nl.getLength());
		set.setSource(extractSource(collectionEle));
		set.setMergeEnabled(parseMergeAttribute(collectionEle));
		for (int i = 0; i < nl.getLength(); i++) {
			if (nl.item(i) instanceof Element) {
				Element ele = (Element) nl.item(i);
				set.add(parsePropertySubElement(ele, bd, defaultTypeClassName));
			}
		}
		return set;
	}

	/**
	 * Parse a map element.
	 */
	public Map parseMapElement(Element mapEle, BeanDefinition bd) {
		String defaultKeyTypeClassName = mapEle.getAttribute(KEY_TYPE_ATTRIBUTE);
		String defaultValueTypeClassName = mapEle.getAttribute(VALUE_TYPE_ATTRIBUTE);

		List entryEles = DomUtils.getChildElementsByTagName(mapEle, ENTRY_ELEMENT);
		ManagedMap map = new ManagedMap(entryEles.size());
		map.setMergeEnabled(parseMergeAttribute(mapEle));
		map.setSource(extractSource(mapEle));

		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 (DomUtils.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 (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;
			boolean hasKeyAttribute = entryEle.hasAttribute(KEY_ATTRIBUTE);
			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) {
				key = buildTypedStringValueForMap(
						entryEle.getAttribute(KEY_ATTRIBUTE), defaultKeyTypeClassName, entryEle);
			}
			else if (hasKeyRefAttribute) {
				String refName = entryEle.getAttribute(KEY_REF_ATTRIBUTE);
				if (!StringUtils.hasText(refName)) {
					error("<entry> element contains empty 'key-ref' attribute", entryEle);
				}
				RuntimeBeanReference ref = new RuntimeBeanReference(refName);
				ref.setSource(extractSource(entryEle));
				key = ref;
			}
			else if (keyEle != null) {
				key = parseKeyElement(keyEle, bd, defaultKeyTypeClassName);
			}
			else {
				error("<entry> element must specify a key", entryEle);
			}

			// 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) {
				error("<entry> element is only allowed to contain either " +
								"'value' attribute OR 'value-ref' attribute OR <value> sub-element", entryEle);
			}
			if (hasValueAttribute) {
				value = buildTypedStringValueForMap(
						entryEle.getAttribute(VALUE_ATTRIBUTE), defaultValueTypeClassName, entryEle);
			}
			else if (hasValueRefAttribute) {
				String refName = entryEle.getAttribute(VALUE_REF_ATTRIBUTE);
				if (!StringUtils.hasText(refName)) {
					error("<entry> element contains empty 'value-ref' attribute", entryEle);
				}
				RuntimeBeanReference ref = new RuntimeBeanReference(refName);
				ref.setSource(extractSource(entryEle));
				value = ref;
			}
			else if (valueEle != null) {
				value = parsePropertySubElement(valueEle, bd, defaultValueTypeClassName);
			}
			else {
				error("<entry> element must specify a value", entryEle);
			}

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

		return map;
	}

	/**
	 * Build a typed String value Object for the given raw value.
	 * @see org.springframework.beans.factory.config.TypedStringValue
	 */
	protected final Object buildTypedStringValueForMap(String value, String defaultTypeClassName, Element entryEle) {
		try {
			return buildTypedStringValue(value, defaultTypeClassName, entryEle);
		}
		catch (ClassNotFoundException ex) {
			error("Type class [" + defaultTypeClassName + "] not found for Map key/value type", entryEle, ex);
			return value;
		}
	}

	/**
	 * Parse a key sub-element of a map element.
	 */
	public Object parseKeyElement(Element keyEle, BeanDefinition bd, String defaultKeyTypeClassName) {
		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) {
					error("<key> element must not contain more than one value sub-element", keyEle);
				}
				else {
					subElement = candidateEle;
				}
			}
		}
		return parsePropertySubElement(subElement, bd, defaultKeyTypeClassName);
	}

	/**
	 * Parse a props element.
	 */
	public Properties parsePropsElement(Element propsEle) {
		ManagedProperties props = new ManagedProperties();
		props.setSource(extractSource(propsEle));
		props.setMergeEnabled(parseMergeAttribute(propsEle));

		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();

			TypedStringValue keyHolder = new TypedStringValue(key);
			keyHolder.setSource(extractSource(propEle));
			TypedStringValue valueHolder = new TypedStringValue(value);
			valueHolder.setSource(extractSource(propEle));
			props.put(keyHolder, valueHolder);
		}

		return props;
	}

	/**
	 * Parse the merge attribute of a collection element, if any.
	 */
	public boolean parseMergeAttribute(Element collectionElement) {
		String value = collectionElement.getAttribute(MERGE_ATTRIBUTE);
		if (DEFAULT_VALUE.equals(value)) {
			value = this.defaults.getMerge();
		}
		return TRUE_VALUE.equals(value);
	}

	public BeanDefinition parseCustomElement(Element ele) {
		return parseCustomElement(ele, null);
	}

	public BeanDefinition parseCustomElement(Element ele, BeanDefinition containingBd) {
		String namespaceUri = ele.getNamespaceURI();
		NamespaceHandler handler = this.readerContext.getNamespaceHandlerResolver().resolve(namespaceUri);
		if (handler == null) {
			error("Unable to locate Spring NamespaceHandler for XML schema namespace [" + namespaceUri + "]", ele);
			return null;
		}
		return handler.parse(ele, new ParserContext(this.readerContext, this, containingBd));
	}

	public BeanDefinitionHolder decorateBeanDefinitionIfRequired(Element ele, BeanDefinitionHolder definitionHolder) {
		BeanDefinitionHolder finalDefinition = definitionHolder;

		// Decorate based on custom attributes first.
		NamedNodeMap attributes = ele.getAttributes();
		for (int i = 0; i < attributes.getLength(); i++) {
			Node node = attributes.item(i);
			finalDefinition = decorateIfRequired(node, finalDefinition);
		}

		// Decorate based on custom nested elements.
		NodeList children = ele.getChildNodes();
		for (int i = 0; i < children.getLength(); i++) {
			Node node = children.item(i);
			if (node.getNodeType() == Node.ELEMENT_NODE) {
				finalDefinition = decorateIfRequired(node, finalDefinition);
			}
		}
		return finalDefinition;
	}

	private BeanDefinitionHolder decorateIfRequired(Node node, BeanDefinitionHolder originalDefinition) {
		String namespaceUri = node.getNamespaceURI();
		if (!isDefaultNamespace(namespaceUri)) {
			NamespaceHandler handler = this.readerContext.getNamespaceHandlerResolver().resolve(namespaceUri);
			if (handler != null) {
				return handler.decorate(node, originalDefinition, new ParserContext(this.readerContext, this));
			}
			else {
				// A custom namespace, not to be handled by Spring - maybe "xml:...".
				if (logger.isDebugEnabled()) {
					logger.debug("No Spring NamespaceHandler found for XML schema namespace [" + namespaceUri + "]");
				}
			}
		}
		return originalDefinition;
	}

	public boolean isDefaultNamespace(String namespaceUri) {
		return (!StringUtils.hasLength(namespaceUri) || BEANS_NAMESPACE_URI.equals(namespaceUri));
	}

	private BeanDefinitionHolder parseNestedCustomElement(Element ele, BeanDefinition containingBd) {
		BeanDefinition innerDefinition = parseCustomElement(ele, containingBd);
		if (innerDefinition == null) {
			error("Incorrect usage of element '" + ele.getNodeName() + "' in a nested manner. " +
					"This tag cannot be used nested inside <property>.", ele);
			return null;
		}
		String id = ele.getNodeName() + BeanDefinitionReaderUtils.GENERATED_BEAN_NAME_SEPARATOR +
				ObjectUtils.getIdentityHexString(innerDefinition);
		if (logger.isDebugEnabled()) {
			logger.debug("Using generated bean name [" + id +
					"] for nested custom element '" + ele.getNodeName() + "'");
		}
		return new BeanDefinitionHolder(innerDefinition, id);
	}

}