propertiesbeandefinitionreader.java

一个关于Spring框架的示例应用程序,简单使用,可以参考.

		// Simply create a map and call overloaded method
		Map map = new HashMap();
		Enumeration keys = rb.getKeys();
		while (keys.hasMoreElements()) {
			String key = (String) keys.nextElement();
			map.put(key, rb.getObject(key));
		}
		return registerBeanDefinitions(map, prefix);
	}

	/**
	 * Register bean definitions contained in a Map,
	 * using all property keys (i.e. not filtering by prefix).
	 * @param map Map name -> property (String or Object). Property values
	 * will be strings if coming from a Properties file etc. Property names
	 * (keys) <b>must</b> be Strings. Class keys must be Strings.
	 * @return the number of bean definitions found
	 * @throws BeansException in case of loading or parsing errors
	 * @see #registerBeanDefinitions(java.util.Map, String, String)
	 */
	public int registerBeanDefinitions(Map map) throws BeansException {
		return registerBeanDefinitions(map, null);
	}

	/**
	 * Register bean definitions contained in a Map.
	 * Ignore ineligible properties.
	 * @param map Map name -> property (String or Object). Property values
	 * will be strings if coming from a Properties file etc. Property names
	 * (keys) <b>must</b> be Strings. Class keys must be Strings.
	 * @param prefix The match or filter within the keys in the map: e.g. 'beans.'
	 * @return the number of bean definitions found
	 * @throws BeansException in case of loading or parsing errors
	 */
	public int registerBeanDefinitions(Map map, String prefix) throws BeansException {
		return registerBeanDefinitions(map, prefix, "Map " + map);
	}

	/**
	 * Register bean definitions contained in a Map.
	 * Ignore ineligible properties.
	 * @param map Map name -> property (String or Object). Property values
	 * will be strings if coming from a Properties file etc. Property names
	 * (keys) <b>must</b> be strings. Class keys must be Strings.
	 * @param prefix match or filter within the keys in the map: e.g. 'beans.'
	 * @param resourceDescription description of the resource that the Map came from
	 * (for logging purposes)
	 * @return the number of bean definitions found
	 * @throws BeansException in case of loading or parsing errors
	 * @see #registerBeanDefinitions(Map, String)
	 */
	public int registerBeanDefinitions(Map map, String prefix, String resourceDescription)
			throws BeansException {

		if (prefix == null) {
			prefix = "";
		}
		int beanCount = 0;

		for (Iterator it = map.keySet().iterator(); it.hasNext();) {
			Object key = it.next();
			if (!(key instanceof String)) {
				throw new IllegalArgumentException("Illegal key [" + key + "]: only Strings allowed");
			}
			String keyString = (String) key;
			if (keyString.startsWith(prefix)) {
				// Key is of form: prefix<name>.property
				String nameAndProperty = keyString.substring(prefix.length());
				// Find dot before property name, ignoring dots in property keys.
				int sepIdx = -1;
				int propKeyIdx = nameAndProperty.indexOf(PropertyAccessor.PROPERTY_KEY_PREFIX);
				if (propKeyIdx != -1) {
					sepIdx = nameAndProperty.lastIndexOf(SEPARATOR, propKeyIdx);
				}
				else {
					sepIdx = nameAndProperty.lastIndexOf(SEPARATOR);
				}
				if (sepIdx != -1) {
					String beanName = nameAndProperty.substring(0, sepIdx);
					if (logger.isDebugEnabled()) {
						logger.debug("Found bean name '" + beanName + "'");
					}
					if (!getBeanFactory().containsBeanDefinition(beanName)) {
						// If we haven't already registered it...
						registerBeanDefinition(beanName, map, prefix + beanName, resourceDescription);
						++beanCount;
					}
				}
				else {
					// Ignore it: It wasn't a valid bean name and property,
					// although it did start with the required prefix.
					if (logger.isDebugEnabled()) {
						logger.debug("Invalid bean name and property [" + nameAndProperty + "]");
					}
				}
			}
		}

		return beanCount;
	}

	/**
	 * Get all property values, given a prefix (which will be stripped)
	 * and add the bean they define to the factory with the given name
	 * @param beanName name of the bean to define
	 * @param map Map containing string pairs
	 * @param prefix prefix of each entry, which will be stripped
	 * @param resourceDescription description of the resource that the Map came from
	 * (for logging purposes)
	 * @throws BeansException if the bean definition could not be parsed or registered
	 */
	protected void registerBeanDefinition(String beanName, Map map, String prefix, String resourceDescription)
			throws BeansException {

		String className = null;
		String parent = null;
		boolean isAbstract = false;
		boolean singleton = true;
		boolean lazyInit = false;

		MutablePropertyValues pvs = new MutablePropertyValues();
		for (Iterator it = map.entrySet().iterator(); it.hasNext();) {
			Map.Entry entry = (Map.Entry) it.next();
			String key = (String) entry.getKey();
			if (key.startsWith(prefix + SEPARATOR)) {
				String property = key.substring(prefix.length() + SEPARATOR.length());
				if (property.equals(CLASS_KEY)) {
					className = (String) entry.getValue();
				}
				else if (property.equals(ABSTRACT_KEY)) {
					String val = (String) entry.getValue();
					isAbstract = val.equals(TRUE_VALUE);
				}
				else if (property.equals(SINGLETON_KEY)) {
					String val = (String) entry.getValue();
					singleton = (val == null) || val.equals(TRUE_VALUE);
				}
				else if (property.equals(LAZY_INIT_KEY)) {
					String val = (String) entry.getValue();
					lazyInit = val.equals(TRUE_VALUE);
				}
				else if (property.equals(PARENT_KEY)) {
					parent = (String) entry.getValue();
				}
				else if (property.endsWith(REF_SUFFIX)) {
					// This isn't a real property, but a reference to another prototype
					// Extract property name: property is of form dog(ref)
					property = property.substring(0, property.length() - REF_SUFFIX.length());
					String ref = (String) entry.getValue();

					// It doesn't matter if the referenced bean hasn't yet been registered:
					// this will ensure that the reference is resolved at rungime
					// Default is not to use singleton
					Object val = new RuntimeBeanReference(ref);
					pvs.addPropertyValue(new PropertyValue(property, val));
				}
				else{
					// normal bean property
					Object val = entry.getValue();
					if (val instanceof String) {
						String strVal = (String) val;
						// if it starts with a reference prefix...
						if (strVal.startsWith(REF_PREFIX)) {
							// expand reference
							String targetName = strVal.substring(1);
							if (targetName.startsWith(REF_PREFIX)) {
								// escaped prefix -> use plain value
								val = targetName;
							}
							else {
								val = new RuntimeBeanReference(targetName);
							}
						}
					}
					pvs.addPropertyValue(new PropertyValue(property, val));
				}
			}
		}

		if (logger.isDebugEnabled()) {
			logger.debug("Registering bean definition for bean name '" + beanName + "' with " + pvs);
		}

		// Just use default parent if we're not dealing with the parent itself,
		// and if there's no class name specified. The latter has to happen for
		// backwards compatibility reasons.
		if (parent == null && className == null && !beanName.equals(this.defaultParentBean)) {
			parent = this.defaultParentBean;
		}

		try {
			AbstractBeanDefinition bd = BeanDefinitionReaderUtils.createBeanDefinition(
					className, parent, null, pvs, getBeanClassLoader());
			bd.setAbstract(isAbstract);
			bd.setSingleton(singleton);
			bd.setLazyInit(lazyInit);
			getBeanFactory().registerBeanDefinition(beanName, bd);
		}
		catch (ClassNotFoundException ex) {
			throw new BeanDefinitionStoreException(resourceDescription, beanName,
					"Bean class [" + className + "] not found", ex);
		}
		catch (NoClassDefFoundError err) {
			throw new BeanDefinitionStoreException(resourceDescription, beanName,
					"Class that bean class [" + className + "] depends on not found", err);
		}
	}

}