jodd.servlet.ServletAction Maven / Gradle / Ivy
// Copyright (c) 2003-2010, Jodd Team (jodd.org). All Rights Reserved.
package jodd.servlet;
import jodd.util.StringUtil;
import java.io.IOException;
import java.lang.reflect.Method;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Replacement and enhancement of HttpServlet, containing additional
* functionalities.
*
*
* Here both POST and GET requests calls doRequest method, which
* is the entering point of the servlet. For more easier work, this servlet
* may use one of the helper methods. Helper methods can be grouped in 3
* groups:
*
*
*
* - invokers - they execute an action. Action may be specified in request
* parameter 'action' or internal, during method invocation. Actions are
* (names of the) methods in the same
ServletAction
* implementation. Action methods can help in reducing the number of
* ServletAction classes, since one class may be used for
* handling more than one request.
*
* - forwarders - perform forwards to specific URL. They also can read
* forward destination from the request parameter 'forward'.
*
* redirectors - perform redirect to specific URL. They also can read
* redirect destination from the request parameter 'redirect'.
*
*
* Default forwarders and redirector names given as request parameter are
* either 'forward' or 'redirect' respectively. If more than one parameter
* is needed, they have to be named as 'forward-...' or 'redirect-...'.
*/
public abstract class ServletAction extends HttpServlet {
// ---------------------------------------------------------------- HTTP method
public static final int HTTP_METHOD_UNKNOWN = 0;
public static final int HTTP_METHOD_GET = 1;
public static final int HTTP_METHOD_POST = 2;
private int method = HTTP_METHOD_UNKNOWN;
/**
* Returns HTTP method (POST/GET) which invoked the action.
*/
public int getHttpMethod() {
return method;
}
/**
* Default doGet method, calls {@link #doRequest(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)}.
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
method = HTTP_METHOD_GET;
doRequest(request, response);
}
/**
* Default doPost method, calls {@link #doRequest(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)}.
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
method = HTTP_METHOD_POST;
doRequest(request, response);
}
/**
* Main get/post request handler.
*/
protected void doRequest(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
}
// ---------------------------------------------------------------- UTILTIES: forward
/**
* Performs forward with use of the RequestDispatcher.
*/
public boolean forward(HttpServletRequest request, HttpServletResponse response, String url) throws IOException, ServletException {
return DispatcherUtil.forward(request, response, url);
}
/**
* Performs forward with use of the RequestDispatcher.
* URL is read from the request. If URL doesn't exist, nothing happens.
*
* @return true if parameter found, false otherwise
*/
public boolean forwardParam(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
String url = request.getParameter("forward");
if (url != null) {
return forward(request, response, url);
}
return false;
}
/**
* Performs forward where URL is read from the request. If URL doesn't exist,
* nothing happens.
*
* @return true if parameter found and forward was successful,
* false otherwise
*/
public boolean forwardParam(HttpServletRequest request, HttpServletResponse response, String s) throws IOException, ServletException {
String url = request.getParameter("forward-" + s);
if (url != null) {
return forward(request, response, url);
}
return false;
}
// ---------------------------------------------------------------- UTILTIES: redirect
/**
* Performs redirection.
*/
protected static void redirect(HttpServletRequest request, HttpServletResponse response, String url) throws IOException {
DispatcherUtil.redirect(request, response, url);
}
/**
* Performs redirection. URL is read from the request. If URL doesn't exist,
* nothing happens.
*
* @return true if parameter found, false otherwise
*/
protected static boolean redirectParam(HttpServletRequest request, HttpServletResponse response) throws IOException {
String url = request.getParameter("redirect");
if (url != null) {
redirect(request, response, url);
return true;
}
return false;
}
/**
* Performs redirection where URL is read from the request. If URL doesn't
* exist, nothing happens.
*
* @return true if parameter found, false otherwise
*/
protected static boolean redirectParam(HttpServletRequest request, HttpServletResponse response, String s) throws IOException {
String url = request.getParameter("redirect-" + s);
if (url != null) {
redirect(request, response, url);
return true;
}
return false;
}
// ---------------------------------------------------------------- UTILTIES: invokers
/**
* Calls a method defined in the request parameter. Method name is read from
* the request. If method name is null (doesn't exist in the request) nothing
* happens.
*
* @return true if action was invoked, otherwise false
*/
public String invokeActionParam(HttpServletRequest request, HttpServletResponse response) throws ServletException {
String actionName = request.getParameter("action");
return invokeActionParam(this, request, response, actionName);
}
/**
* Invoke a method from this ServletAction class. Methods name is given as
* parameter. If method name is null nothing happens.
*
* @return null if error, otherwise string mapping
*/
public String invokeActionParam(Object servlet, HttpServletRequest request, HttpServletResponse response, String actionName) throws ServletException {
if (actionName == null) {
return null;
}
try {
Method m = servlet.getClass().getMethod(actionName, HttpServletRequest.class, HttpServletResponse.class);
Object result = m.invoke(servlet, request, response);
return StringUtil.toString(result);
} catch (Exception ex) {
throw new ServletException("Invocation error of action '" + actionName + "': " + ex.getMessage(), ex);
}
}
// ---------------------------------------------------------------- UTILITIES: include
/**
* Performs include page.
*/
public static boolean include(HttpServletRequest request, HttpServletResponse response, String page) throws IOException, ServletException {
return DispatcherUtil.include(request, response, page);
}
public static boolean includeParam(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
String url = request.getParameter("include");
if (url != null) {
return include(request, response, url);
}
return false;
}
public static boolean includeParam(HttpServletRequest request, HttpServletResponse response, String includeName) throws IOException, ServletException {
String url = request.getParameter("include-" + includeName);
if (url != null) {
return include(request, response, url);
}
return false;
}
}