org.springframework.beans.factory.xml.AbstractSingleBeanDefinitionParser Maven / Gradle / Ivy
/*
* Copyright 2002-2017 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.beans.factory.xml;
import org.w3c.dom.Element;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.lang.Nullable;
/**
* Base class for those {@link BeanDefinitionParser} implementations that
* need to parse and define just a single {@code BeanDefinition}.
*
* Extend this parser class when you want to create a single bean definition
* from an arbitrarily complex XML element. You may wish to consider extending
* the {@link AbstractSimpleBeanDefinitionParser} when you want to create a
* single bean definition from a relatively simple custom XML element.
*
*
The resulting {@code BeanDefinition} will be automatically registered
* with the {@link org.springframework.beans.factory.support.BeanDefinitionRegistry}.
* Your job simply is to {@link #doParse parse} the custom XML {@link Element}
* into a single {@code BeanDefinition}.
*
* @author Rob Harrop
* @author Juergen Hoeller
* @author Rick Evans
* @since 2.0
* @see #getBeanClass
* @see #getBeanClassName
* @see #doParse
*/
public abstract class AbstractSingleBeanDefinitionParser extends AbstractBeanDefinitionParser {
/**
* Creates a {@link BeanDefinitionBuilder} instance for the
* {@link #getBeanClass bean Class} and passes it to the
* {@link #doParse} strategy method.
* @param element the element that is to be parsed into a single BeanDefinition
* @param parserContext the object encapsulating the current state of the parsing process
* @return the BeanDefinition resulting from the parsing of the supplied {@link Element}
* @throws IllegalStateException if the bean {@link Class} returned from
* {@link #getBeanClass(org.w3c.dom.Element)} is {@code null}
* @see #doParse
*/
@Override
protected final AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext) {
BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition();
String parentName = getParentName(element);
if (parentName != null) {
builder.getRawBeanDefinition().setParentName(parentName);
}
Class beanClass = getBeanClass(element);
if (beanClass != null) {
builder.getRawBeanDefinition().setBeanClass(beanClass);
}
else {
String beanClassName = getBeanClassName(element);
if (beanClassName != null) {
builder.getRawBeanDefinition().setBeanClassName(beanClassName);
}
}
builder.getRawBeanDefinition().setSource(parserContext.extractSource(element));
BeanDefinition containingBd = parserContext.getContainingBeanDefinition();
if (containingBd != null) {
// Inner bean definition must receive same scope as containing bean.
builder.setScope(containingBd.getScope());
}
if (parserContext.isDefaultLazyInit()) {
// Default-lazy-init applies to custom bean definitions as well.
builder.setLazyInit(true);
}
doParse(element, parserContext, builder);
return builder.getBeanDefinition();
}
/**
* Determine the name for the parent of the currently parsed bean,
* in case of the current bean being defined as a child bean.
*
The default implementation returns {@code null},
* indicating a root bean definition.
* @param element the {@code Element} that is being parsed
* @return the name of the parent bean for the currently parsed bean,
* or {@code null} if none
*/
@Nullable
protected String getParentName(Element element) {
return null;
}
/**
* Determine the bean class corresponding to the supplied {@link Element}.
*
Note that, for application classes, it is generally preferable to
* override {@link #getBeanClassName} instead, in order to avoid a direct
* dependence on the bean implementation class. The BeanDefinitionParser
* and its NamespaceHandler can be used within an IDE plugin then, even
* if the application classes are not available on the plugin's classpath.
* @param element the {@code Element} that is being parsed
* @return the {@link Class} of the bean that is being defined via parsing
* the supplied {@code Element}, or {@code null} if none
* @see #getBeanClassName
*/
@Nullable
protected Class getBeanClass(Element element) {
return null;
}
/**
* Determine the bean class name corresponding to the supplied {@link Element}.
* @param element the {@code Element} that is being parsed
* @return the class name of the bean that is being defined via parsing
* the supplied {@code Element}, or {@code null} if none
* @see #getBeanClass
*/
@Nullable
protected String getBeanClassName(Element element) {
return null;
}
/**
* Parse the supplied {@link Element} and populate the supplied
* {@link BeanDefinitionBuilder} as required.
*
The default implementation delegates to the {@code doParse}
* version without ParserContext argument.
* @param element the XML element being parsed
* @param parserContext the object encapsulating the current state of the parsing process
* @param builder used to define the {@code BeanDefinition}
* @see #doParse(Element, BeanDefinitionBuilder)
*/
protected void doParse(Element element, ParserContext parserContext, BeanDefinitionBuilder builder) {
doParse(element, builder);
}
/**
* Parse the supplied {@link Element} and populate the supplied
* {@link BeanDefinitionBuilder} as required.
*
The default implementation does nothing.
* @param element the XML element being parsed
* @param builder used to define the {@code BeanDefinition}
*/
protected void doParse(Element element, BeanDefinitionBuilder builder) {
}
}