org.eclipse.rdf4j.http.server.ServerInterceptor Maven / Gradle / Ivy

Go to download
/*******************************************************************************
 * Copyright (c) 2015 Eclipse RDF4J contributors, Aduna, and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Distribution License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *******************************************************************************/
package org.eclipse.rdf4j.http.server;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

/**
 * Base class for single-use request interceptors. This implementation sets the thread name to something
 * sensible at the start of the request handling and resets the name at the end. This is useful for logging
 * frameworks that make use of thread names, such as Log4J. Should not be a singleton bean! Configure as inner
 * bean in openrdf-servlet.xml
 * 
 * @author Herko ter Horst
 */
public abstract class ServerInterceptor extends HandlerInterceptorAdapter {

	private String origThreadName;

	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
		throws Exception
	{
		origThreadName = Thread.currentThread().getName();
		Thread.currentThread().setName(getThreadName());

		setRequestAttributes(request);

		return super.preHandle(request, response, handler);
	}

	@Override
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
			Exception exception)
		throws Exception
	{
		cleanUpResources();
		Thread.currentThread().setName(origThreadName);
	}

	/**
	 * Determine the thread name to use. Called before the request is forwarded to a handler.
	 * 
	 * @return a name that makes sense based on the request
	 * @throws ServerHTTPException
	 *         if it was impossible to determine a name due to an internal error
	 */
	protected abstract String getThreadName()
		throws ServerHTTPException;

	/**
	 * Set attributes for this request. Called before the request is forwarded to a handler. By default, this
	 * method does nothing.
	 * 
	 * @param request
	 *        the request
	 * @throws ClientHTTPException
	 *         if it was impossible to set one or more attributes due to a bad request on the part of the
	 *         client
	 * @throws ServerHTTPException
	 *         if it was impossible to set one or more attributes due to an internal error
	 */
	protected void setRequestAttributes(HttpServletRequest request)
		throws ClientHTTPException, ServerHTTPException
	{
	}

	/**
	 * Clean up resources used in handling this request. Called after the request is handled and a the view is
	 * rendered (or an exception has occurred). By default, this method does nothing.
	 * 
	 * @throws ServerHTTPException
	 *         if some resources could not be cleaned up because of an internal error
	 */
	protected void cleanUpResources()
		throws ServerHTTPException
	{
	}
}