package org.frameworkset.web.filter;
import java.util.HashSet;
import java.util.Set;
import javax.servlet.Filter;
import javax.servlet.FilterConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import org.apache.log4j.Logger;
import org.frameworkset.spi.BeanNameAware;
import org.frameworkset.spi.DisposableBean;
import org.frameworkset.spi.InitializingBean;
import org.frameworkset.util.Assert;
import org.frameworkset.util.beans.BeanWrapper;
import org.frameworkset.util.beans.BeansException;
import org.frameworkset.web.servlet.context.ServletContextAware;
/**
* Simple base implementation of {@link javax.servlet.Filter} which treats
* its config parameters ({@code init-param} entries within the
* {@code filter} tag in {@code web.xml}) as bean properties.
*
* <p>A handy superclass for any type of filter. Type conversion of config
* parameters is automatic, with the corresponding setter method getting
* invoked with the converted value. It is also possible for subclasses to
* specify required properties. Parameters without matching bean property
* setter will simply be ignored.
*
* <p>This filter leaves actual filtering to subclasses, which have to
* implement the {@link javax.servlet.Filter#doFilter} method.
*
* <p>This generic filter base class has no dependency on the Spring
* {@link org.frameworkset.context.ApplicationContext} concept.
* Filters usually don't load their own context but rather access service
* beans from the Spring root application context, accessible via the
* filter's {@link #getServletContext() ServletContext} (see
* {@link org.frameworkset.web.context.support.WebApplicationContextUtils}).
*
* @author Juergen Hoeller
* @since 06.12.2003
* @see #addRequiredProperty
* @see #initFilterBean
* @see #doFilter
*/
public abstract class GenericFilterBean implements
Filter, BeanNameAware, ServletContextAware, InitializingBean, DisposableBean {
/** Logger available to subclasses */
protected static final Logger logger = Logger.getLogger(GenericFilterBean.class);
/**
* Set of required properties (Strings) that must be supplied as
* config parameters to this filter.
*/
private final Set<String> requiredProperties = new HashSet<String>();
private FilterConfig filterConfig;
private String beanName;
private ServletContext servletContext;
/**
* Stores the bean name as defined in the Spring bean factory.
* <p>Only relevant in case of initialization as bean, to have a name as
* fallback to the filter name usually provided by a FilterConfig instance.
* @see org.frameworkset.beans.factory.BeanNameAware
* @see #getFilterName()
*/
@Override
public final void setBeanName(String beanName) {
this.beanName = beanName;
}
/**
* Stores the ServletContext that the bean factory runs in.
* <p>Only relevant in case of initialization as bean, to have a ServletContext
* as fallback to the context usually provided by a FilterConfig instance.
* @see org.frameworkset.web.context.ServletContextAware
* @see #getServletContext()
*/
@Override
public final void setServletContext(ServletContext servletContext) {
this.servletContext = servletContext;
}
/**
* Calls the {@code initFilterBean()} method that might
* contain custom initialization of a subclass.
* <p>Only relevant in case of initialization as bean, where the
* standard {@code init(FilterConfig)} method won't be called.
* @see #initFilterBean()
* @see #init(javax.servlet.FilterConfig)
*/
@Override
public void afterPropertiesSet() throws ServletException {
initFilterBean();
}
/**
* Subclasses can invoke this method to specify that this property
* (which must match a JavaBean property they expose) is mandatory,
* and must be supplied as a config parameter. This should be called
* from the constructor of a subclass.
* <p>This method is only relevant in case of traditional initialization
* driven by a FilterConfig instance.
* @param property name of the required property
*/
protected final void addRequiredProperty(String property) {
this.requiredProperties.add(property);
}
/**
* Standard way of initializing this filter.
* Map config parameters onto bean properties of this filter, and
* invoke subclass initialization.
* @param filterConfig the configuration for this filter
* @throws ServletException if bean properties are invalid (or required
* properties are missing), or if subclass initialization fails.
* @see #initFilterBean
*/
@Override
public final void init(FilterConfig filterConfig) throws ServletException {
Assert.notNull(filterConfig, "FilterConfig must not be null");
if (logger.isDebugEnabled()) {
logger.debug("Initializing filter '" + filterConfig.getFilterName() + "'");
}
this.filterConfig = filterConfig;
// // Set bean properties from init parameters.
// try {
// PropertyValues pvs = new FilterConfigPropertyValues(filterConfig, this.requiredProperties);
// BeanWrapper bw = PropertyAccessorFactory.forBeanPropertyAccess(this);
// ResourceLoader resourceLoader = new ServletContextResourceLoader(filterConfig.getServletContext());
// bw.registerCustomEditor(Resource.class, new ResourceEditor(resourceLoader, this.environment));
// initBeanWrapper(bw);
// bw.setPropertyValues(pvs, true);
// }
// catch (BeansException ex) {
// String msg = "Failed to set bean properties on filter '" +
// filterConfig.getFilterName() + "': " + ex.getMessage();
// logger.error(msg, ex);
// throw new NestedServletException(msg, ex);
// }
// Let subclasses do whatever initialization they like.
initFilterBean();
if (logger.isDebugEnabled()) {
logger.debug("Filter '" + filterConfig.getFilterName() + "' configured successfully");
}
}
/**
* Initialize the BeanWrapper for this GenericFilterBean,
* possibly with custom editors.
* <p>This default implementation is empty.
* @param bw the BeanWrapper to initialize
* @throws BeansException if thrown by BeanWrapper methods
* @see org.frameworkset.beans.BeanWrapper#registerCustomEditor
*/
protected void initBeanWrapper(BeanWrapper bw) throws BeansException {
}
/**
* Make the FilterConfig of this filter available, if any.
* Analogous to GenericServlet's {@code getServletConfig()}.
* <p>Public to resemble the {@code getFilterConfig()} method
* of the Servlet Filter version that shipped with WebLogic 6.1.
* @return the FilterConfig instance, or {@code null} if none available
* @see javax.servlet.GenericServlet#getServletConfig()
*/
public final FilterConfig getFilterConfig() {
return this.filterConfig;
}
/**
* Make the name of this filter available to subclasses.
* Analogous to GenericServlet's {@code getServletName()}.
* <p>Takes the FilterConfig's filter name by default.
* If initialized as bean in a Spring application context,
* it falls back to the bean name as defined in the bean factory.
* @return the filter name, or {@code null} if none available
* @see javax.servlet.GenericServlet#getServletName()
* @see javax.servlet.FilterConfig#getFilterName()
* @see #setBeanName
*/
protected final String getFilterName() {
return (this.filterConfig != null ? this.filterConfig.getFilterName() : this.beanName);
}
/**
* Make the ServletContext of this filter available to subclasses.
* Analogous to GenericServlet's {@code getServletContext()}.
* <p>Takes the FilterConfig's ServletContext by default.
* If initialized as bean in a Spring application context,
* it falls back to the ServletContext that the bean factory runs in.
* @return the ServletContext instance, or {@code null} if none available
* @see javax.servlet.GenericServlet#getServletContext()
* @see javax.servlet.FilterConfig#getServletContext()
* @see #setServletContext
*/
protected final ServletContext getServletContext() {
return (this.filterConfig != null ? this.filterConfig.getServletContext() : this.servletContext);
}
/**
* Subclasses may override this to perform custom initialization.
* All bean properties of this filter will have been set before this
* method is invoked.
* <p>Note: This method will be called from standard filter initialization
* as well as filter bean initialization in a Spring application context.
* Filter name and ServletContext will be available in both cases.
* <p>This default implementation is empty.
* @throws ServletException if subclass initialization fails
* @see #getFilterName()
* @see #getServletContext()
*/
protected void initFilterBean() throws ServletException {
}
/**
* Subclasses may override this to perform custom filter shutdown.
* <p>Note: This method will be called from standard filter destruction
* as well as filter bean destruction in a Spring application context.
* <p>This default implementation is empty.
*/
@Override
public void destroy() {
}
// /**
// * PropertyValues implementation created from FilterConfig init parameters.
// */
// @SuppressWarnings("serial")
// private static class FilterConfigPropertyValues extends MutablePropertyValues {
//
// /**
// * Create new FilterConfigPropertyValues.
// * @param config FilterConfig we'll use to take PropertyValues from
// * @param requiredProperties set of property names we need, where
// * we can't accept default values
// * @throws ServletException if any required properties are missing
// */
// public FilterConfigPropertyValues(FilterConfig config, Set<String> requiredProperties)
// throws ServletException {
//
// Set<String> missingProps = (requiredProperties != null && !requiredProperties.isEmpty()) ?
// new HashSet<String>(requiredProperties) : null;
//
// Enumeration<?> en = config.getInitParameterNames();
// while (en.hasMoreElements()) {
// String property = (String) en.nextElement();
// Object value = config.getInitParameter(property);
// addPropertyValue(new PropertyValue(property, value));
// if (missingProps != null) {
// missingProps.remove(property);
// }
// }
//
// // Fail if we are still missing properties.
// if (missingProps != null && missingProps.size() > 0) {
// throw new ServletException(
// "Initialization from FilterConfig for filter '" + config.getFilterName() +
// "' failed; the following required properties were missing: " +
// StringUtil.collectionToDelimitedString(missingProps, ", "));
// }
// }
// }
}