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A BeanDefinitionParser will be used if the
NamespaceHandler encounters an XML element of the type
that has been mapped to the specific bean definition parser (which is 'dateformat'
in this case). In other words, the BeanDefinitionParser is
responsible for parsing one distinct top-level XML element defined in the
schema. In the parser, we'll have access to the XML element (and thus it's subelements too)
so that we can parse our custom XML content, as can be seen in the following example:
package org.springframework.samples.xml;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.xml.AbstractSingleBeanDefinitionParser;
import org.springframework.util.StringUtils;
import org.w3c.dom.Element;
import java.text.SimpleDateFormat;
public class SimpleDateFormatBeanDefinitionParser extends AbstractSingleBeanDefinitionParser { 
protected Class getBeanClass(Element element) {
return SimpleDateFormat.class; 
}
protected void doParse(Element element, BeanDefinitionBuilder bean) {
// this will never be null since the schema explicitly requires that a value be supplied
String pattern = element.getAttribute("pattern");
bean.addConstructorArg(pattern);
// this however is an optional property
String lenient = element.getAttribute("lenient");
if (StringUtils.hasText(lenient)) {
bean.addPropertyValue("lenient", Boolean.valueOf(lenient));
}
}
}
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We use the Spring-provided |
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We supply the |
In this simple case, this is all that we need to do. The creation of our single
BeanDefinition is handled by the AbstractSingleBeanDefinitionParser
superclass, as is the extraction and setting of the bean definition's unique identifier.