xmlbeandefinitionreader.java

spring api 源代码

	/**
	 * Set the XmlBeanDefinitionParser implementation to use,
	 * responsible for the actual parsing of XML bean definitions.
	 * @deprecated as of Spring 2.0: superseded by "documentReaderClass"
	 * @see #setDocumentReaderClass
	 * @see XmlBeanDefinitionParser
	 */
	public void setParserClass(Class parserClass) {
		if (this.parserClass == null || !XmlBeanDefinitionParser.class.isAssignableFrom(parserClass)) {
			throw new IllegalArgumentException("'parserClass' must be an XmlBeanDefinitionParser");
		}
		this.parserClass = parserClass;
	}

	/**
	 * Specify the BeanDefinitionDocumentReader implementation to use,
	 * responsible for the actual reading of the XML bean definition document.
	 * <p>Default is DefaultBeanDefinitionDocumentReader.
	 * @param documentReaderClass the desired BeanDefinitionDocumentReader implementation class
	 * @see BeanDefinitionDocumentReader
	 * @see DefaultBeanDefinitionDocumentReader
	 */
	public void setDocumentReaderClass(Class documentReaderClass) {
		if (documentReaderClass == null || !BeanDefinitionDocumentReader.class.isAssignableFrom(documentReaderClass)) {
			throw new IllegalArgumentException(
					"documentReaderClass must be an implementation of the BeanDefinitionDocumentReader interface");
		}
		this.documentReaderClass = documentReaderClass;
	}


	/**
	 * Load bean definitions from the specified XML file.
	 * @param resource the resource descriptor for the XML file
	 * @return the number of bean definitions found
	 * @throws BeanDefinitionStoreException in case of loading or parsing errors
	 */
	public int loadBeanDefinitions(Resource resource) throws BeanDefinitionStoreException {
		return loadBeanDefinitions(new EncodedResource(resource));
	}

	/**
	 * Load bean definitions from the specified XML file.
	 * @param encodedResource the resource descriptor for the XML file,
	 * allowing to specify an encoding to use for parsing the file
	 * @return the number of bean definitions found
	 * @throws BeanDefinitionStoreException in case of loading or parsing errors
	 */
	public int loadBeanDefinitions(EncodedResource encodedResource) throws BeanDefinitionStoreException {
		Assert.notNull(encodedResource, "EncodedResource must not be null");
		if (logger.isInfoEnabled()) {
			logger.info("Loading XML bean definitions from " + encodedResource.getResource());
		}

		try {
			InputStream inputStream = encodedResource.getResource().getInputStream();
			try {
				InputSource inputSource = new InputSource(inputStream);
				if (encodedResource.getEncoding() != null) {
					inputSource.setEncoding(encodedResource.getEncoding());
				}
				return doLoadBeanDefinitions(inputSource, encodedResource.getResource());
			}
			finally {
				inputStream.close();
			}
		}
		catch (IOException ex) {
			throw new BeanDefinitionStoreException(
					"IOException parsing XML document from " + encodedResource.getResource(), ex);
		}
	}

	/**
	 * Load bean definitions from the specified XML file.
	 * @param inputSource the SAX InputSource to read from
	 * @return the number of bean definitions found
	 * @throws BeanDefinitionStoreException in case of loading or parsing errors
	 */
	public int loadBeanDefinitions(InputSource inputSource) throws BeanDefinitionStoreException {
		return loadBeanDefinitions(inputSource, "resource loaded through SAX InputSource");
	}

	/**
	 * Load bean definitions from the specified XML file.
	 * @param inputSource the SAX InputSource to read from
	 * @param resourceDescription a description of the resource
	 * (can be <code>null</code> or empty)
	 * @return the number of bean definitions found
	 * @throws BeanDefinitionStoreException in case of loading or parsing errors
	 */
	public int loadBeanDefinitions(InputSource inputSource, String resourceDescription)
			throws BeanDefinitionStoreException {

		return doLoadBeanDefinitions(inputSource, new DescriptiveResource(resourceDescription));
	}


	/**
	 * Actually load bean definitions from the specified XML file.
	 * @param inputSource the SAX InputSource to read from
	 * @param resource the resource descriptor for the XML file
	 * @return the number of bean definitions found
	 * @throws BeanDefinitionStoreException in case of loading or parsing errors
	 */
	protected int doLoadBeanDefinitions(InputSource inputSource, Resource resource)
			throws BeanDefinitionStoreException {
		try {
			int validationMode = getValidationModeForResource(resource);
			Document doc = this.documentLoader.loadDocument(
					inputSource, getEntityResolver(), this.errorHandler, validationMode, this.namespaceAware);
			return registerBeanDefinitions(doc, resource);
		}
		catch (BeanDefinitionStoreException ex) {
			throw ex;
		}
		catch (SAXParseException ex) {
			throw new XmlBeanDefinitionStoreException(resource.getDescription(),
					"Line " + ex.getLineNumber() + " in XML document from " + resource + " is invalid", ex);
		}
		catch (SAXException ex) {
			throw new XmlBeanDefinitionStoreException(resource.getDescription(),
					"XML document from " + resource + " is invalid", ex);
		}
		catch (ParserConfigurationException ex) {
			throw new BeanDefinitionStoreException(resource.getDescription(),
					"Parser configuration exception parsing XML from " + resource, ex);
		}
		catch (IOException ex) {
			throw new BeanDefinitionStoreException(resource.getDescription(),
					"IOException parsing XML document from " + resource, ex);
		}
		catch (Throwable ex) {
			throw new BeanDefinitionStoreException(resource.getDescription(),
					"Unexpected exception parsing XML document from " + resource, ex);
		}
	}


	/**
	 * Gets the validation mode for the specified {@link Resource}. If no explicit
	 * validation mode has been configured then the validation mode is
	 * {@link #detectValidationMode detected}.
	 */
	private int getValidationModeForResource(Resource resource) {
		if (this.validationMode != VALIDATION_AUTO) {
			return this.validationMode;
		}
		int detectedMode = detectValidationMode(resource);
		if (detectedMode != VALIDATION_AUTO) {
			return detectedMode;
		}
		// Hmm, we didn't get a clear indication... Let's assume XSD,
		// since apparently no DTD declaration has been found up until
		// detection stopped (before finding the document's root tag).
		return VALIDATION_XSD;
	}

	/**
	 * Detects which kind of validation to perform on the XML file identified
	 * by the supplied {@link Resource}. If the
	 * file has a <code>DOCTYPE</code> definition then DTD validation is used
	 * otherwise XSD validation is assumed.
	 */
	protected int detectValidationMode(Resource resource) {
		if (resource.isOpen()) {
			throw new BeanDefinitionStoreException(
					"Passed-in Resource [" + resource + "] contains an open stream: " +
					"cannot determine validation mode automatically. Either pass in a Resource " +
					"that is able to create fresh streams, or explicitly specify the validationMode " +
					"on your XmlBeanDefinitionReader instance.");
		}

		InputStream inputStream;
		try {
			inputStream = resource.getInputStream();
		}
		catch (IOException ex) {
			throw new BeanDefinitionStoreException(
					"Unable to determine validation mode for [" + resource + "]: cannot open InputStream. " +
					"Did you attempt to load directly from a SAX InputSource without specifying the " +
					"validationMode on your XmlBeanDefinitionReader instance?", ex);
		}

		try {
			return this.validationModeDetector.detectValidationMode(inputStream);
		}
		catch (IOException ex) {
			throw new BeanDefinitionStoreException("Unable to determine validation mode for [" +
					resource + "]: an error occurred whilst reading from the InputStream.", ex);
		}
	}

	/**
	 * Register the bean definitions contained in the given DOM document.
	 * Called by <code>loadBeanDefinitions</code>.
	 * <p>Creates a new instance of the parser class and invokes
	 * <code>registerBeanDefinitions</code> on it.
	 * @param doc the DOM document
	 * @param resource the resource descriptor (for context information)
	 * @return the number of bean definitions found
	 * @throws BeanDefinitionStoreException in case of parsing errors
	 * @see #loadBeanDefinitions
	 * @see #setDocumentReaderClass
	 * @see BeanDefinitionDocumentReader#registerBeanDefinitions
	 */
	public int registerBeanDefinitions(Document doc, Resource resource) throws BeanDefinitionStoreException {
		// Support old XmlBeanDefinitionParser SPI for backwards-compatibility.
		if (this.parserClass != null) {
			XmlBeanDefinitionParser parser =
					(XmlBeanDefinitionParser) BeanUtils.instantiateClass(this.parserClass);
			return parser.registerBeanDefinitions(this, doc, resource);
		}
		// Read document based on new BeanDefinitionDocumentReader SPI.
		BeanDefinitionDocumentReader documentReader = createBeanDefinitionDocumentReader();
		int countBefore = getBeanFactory().getBeanDefinitionCount();
		documentReader.registerBeanDefinitions(doc, createReaderContext(resource));
		return getBeanFactory().getBeanDefinitionCount() - countBefore;
	}

	/**
	 * Create the {@link BeanDefinitionDocumentReader} to use for actually
	 * reading bean definitions from an XML document.
	 * <p>Default implementation instantiates the specified "documentReaderClass".
	 * @see #setDocumentReaderClass
	 */
	protected BeanDefinitionDocumentReader createBeanDefinitionDocumentReader() {
		return (BeanDefinitionDocumentReader) BeanUtils.instantiateClass(this.documentReaderClass);
	}

	/**
	 * Create the {@link XmlReaderContext} to pass over to the document reader.
	 */
	protected XmlReaderContext createReaderContext(Resource resource) {
		if (this.namespaceHandlerResolver == null) {
			this.namespaceHandlerResolver = createDefaultNamespaceHandlerResolver();
		}
		return new XmlReaderContext(resource, this.problemReporter, this.eventListener,
				this.sourceExtractor, this, this.namespaceHandlerResolver);
	}

	/**
	 * Create the default implementation of {@link NamespaceHandlerResolver} used if none is specified.
	 * Default implementation returns an instance of {@link DefaultNamespaceHandlerResolver}.
	 */
	protected NamespaceHandlerResolver createDefaultNamespaceHandlerResolver() {
		return new DefaultNamespaceHandlerResolver(getResourceLoader().getClassLoader());
	}

}