001/*
002 * Copyright 2002-2011 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.beans.factory.xml;
018
019import org.w3c.dom.Element;
020
021import org.springframework.beans.factory.config.BeanDefinition;
022import org.springframework.lang.Nullable;
023
024/**
025 * Interface used by the {@link DefaultBeanDefinitionDocumentReader} to handle custom,
026 * top-level (directly under {@code <beans/>}) tags.
027 *
028 * <p>Implementations are free to turn the metadata in the custom tag into as many
029 * {@link BeanDefinition BeanDefinitions} as required.
030 *
031 * <p>The parser locates a {@link BeanDefinitionParser} from the associated
032 * {@link NamespaceHandler} for the namespace in which the custom tag resides.
033 *
034 * @author Rob Harrop
035 * @since 2.0
036 * @see NamespaceHandler
037 * @see AbstractBeanDefinitionParser
038 */
039public interface BeanDefinitionParser {
040
041        /**
042         * Parse the specified {@link Element} and register the resulting
043         * {@link BeanDefinition BeanDefinition(s)} with the
044         * {@link org.springframework.beans.factory.xml.ParserContext#getRegistry() BeanDefinitionRegistry}
045         * embedded in the supplied {@link ParserContext}.
046         * <p>Implementations must return the primary {@link BeanDefinition} that results
047         * from the parse if they will ever be used in a nested fashion (for example as
048         * an inner tag in a {@code <property/>} tag). Implementations may return
049         * {@code null} if they will <strong>not</strong> be used in a nested fashion.
050         * @param element the element that is to be parsed into one or more {@link BeanDefinition BeanDefinitions}
051         * @param parserContext the object encapsulating the current state of the parsing process;
052         * provides access to a {@link org.springframework.beans.factory.support.BeanDefinitionRegistry}
053         * @return the primary {@link BeanDefinition}
054         */
055        @Nullable
056        BeanDefinition parse(Element element, ParserContext parserContext);
057
058}