/******************************************************************************
 * Copyright (c) 1999-2013 Holland America Line Inc. All rights reserved. Use,
 * disclosure, and reproduction controlled under license from Holland America
 * Line Inc.
 ****************************************************************************/
package com.hal.sf.interceptor;

import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.StrutsStatics;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.Interceptor;

/**
 * This Interceptor instructs web browsers to not cache any content.
 *
 * <P>
 * <b>Change Log</b><br>
 * <ul>
 * <li>mlr 06/11/2013
 * <ul>
 * <li>Created Object</li>
 * </ul>
 * </li>
 * </ul>
 */
public class CachingHeadersInterceptor implements Interceptor {
	private static final long serialVersionUID = 1L;

	/**
	 * Sole constructor
	 */
	public CachingHeadersInterceptor() {
		// empty constructor
	}

	/**
	 * Method required by Interceptor interface.
	 */
	public void destroy() {
		// empty method.
	}

	/**
	 * Method required by Interceptor interface.
	 */
	public void init() {
		// empty method.
	}

	/**
	 * @param actionInvocation
	 * @throws Exception
	 * @return String
	 */
	public String intercept(final ActionInvocation actionInvocation)
			throws Exception {
		final ActionContext actionContext = actionInvocation.getInvocationContext();
		final HttpServletResponse httpServletResponse = (HttpServletResponse) actionContext
				.get(StrutsStatics.HTTP_RESPONSE);
		if (httpServletResponse != null) {
			httpServletResponse.setHeader("Cache-control", "no-cache, no-store");
			httpServletResponse.setHeader("Pragma", "no-cache");
			httpServletResponse.setHeader("Expires", "-1");
		}
		return actionInvocation.invoke();
	}

}