WasCacheHitCheckServletFilter.java 文件源码

/**
 * Fetch the response wrapper of type CacheProxyResponse if one can be
 * found.
 * 
 * @param servletResponse
 *            the current servlet response.
 * @return the response wrapper of type CacheProxyResponse if one can be
 *         found.
 */
private static CacheProxyResponse fetchCacheProxyResponse(
        ServletResponse servletResponse) {
    CacheProxyResponse cachedResponse = null;
    ServletResponse findResponse = servletResponse;

    while (findResponse instanceof HttpServletResponseWrapper) {
        if (findResponse instanceof CacheProxyResponse) {
            cachedResponse = (CacheProxyResponse) findResponse;
            break;
        }
        HttpServletResponseWrapper wrapper = (HttpServletResponseWrapper) findResponse;
        findResponse = wrapper.getResponse();
    }
    return cachedResponse;
}