Struts example source code file (TagUtils.java)

This example Struts source code file (TagUtils.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Struts tags/keywords

actioninvocation, actionmapping, attributemap, http, httpservletrequest, httpservletrequest, httpservletresponse, map, object, object, request, response, servlet, string, struts, struts, util, valuestack, valuestack

The Struts TagUtils.java source code

/*
 * $Id: TagUtils.java 670170 2008-06-21 09:40:34Z hermanns $
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.struts2.views.jsp;

import java.util.Map;

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

import org.apache.struts2.RequestUtils;
import org.apache.struts2.ServletActionContext;
import org.apache.struts2.dispatcher.ApplicationMap;
import org.apache.struts2.dispatcher.Dispatcher;
import org.apache.struts2.dispatcher.RequestMap;
import org.apache.struts2.dispatcher.SessionMap;
import org.apache.struts2.dispatcher.mapper.ActionMapper;
import org.apache.struts2.dispatcher.mapper.ActionMapping;
import org.apache.struts2.util.AttributeMap;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.config.ConfigurationException;
import com.opensymphony.xwork2.util.ValueStack;
import com.opensymphony.xwork2.util.ValueStackFactory;


/**
 */
public class TagUtils {

    public static ValueStack getStack(PageContext pageContext) {
        HttpServletRequest req = (HttpServletRequest) pageContext.getRequest();
        ValueStack stack = (ValueStack) req.getAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY);

        if (stack == null) {

            HttpServletResponse res = (HttpServletResponse) pageContext.getResponse();
            Dispatcher du = Dispatcher.getInstance();
            if (du == null) {
                throw new ConfigurationException("The Struts dispatcher cannot be found.  This is usually caused by "+
                        "using Struts tags without the associated filter. Struts tags are only usable when the request "+
                        "has passed through its servlet filter, which initializes the Struts dispatcher needed for this tag.");
            }
            stack = du.getContainer().getInstance(ValueStackFactory.class).createValueStack();
            Map<String, Object> extraContext = du.createContextMap(new RequestMap(req),
                    req.getParameterMap(),
                    new SessionMap(req),
                    new ApplicationMap(pageContext.getServletContext()),
                    req,
                    res,
                    pageContext.getServletContext());
            extraContext.put(ServletActionContext.PAGE_CONTEXT, pageContext);
            stack.getContext().putAll(extraContext);
            req.setAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY, stack);

            // also tie this stack/context to the ThreadLocal
            ActionContext.setContext(new ActionContext(stack.getContext()));
        } else {
            // let's make sure that the current page context is in the action context
            Map<String, Object> context = stack.getContext();
            context.put(ServletActionContext.PAGE_CONTEXT, pageContext);

            AttributeMap attrMap = new AttributeMap(context);
            context.put("attr", attrMap);
        }

        return stack;
    }

    public static String buildNamespace(ActionMapper mapper, ValueStack stack, HttpServletRequest request) {
        ActionContext context = new ActionContext(stack.getContext());
        ActionInvocation invocation = context.getActionInvocation();

        if (invocation == null) {
            ActionMapping mapping = mapper.getMapping(request,
                    Dispatcher.getInstance().getConfigurationManager());

            if (mapping != null) {
                return mapping.getNamespace();
            } else {
                // well, if the ActionMapper can't tell us, and there is no existing action invocation,
                // let's just go with a default guess that the namespace is the last the path minus the
                // last part (/foo/bar/baz.xyz -> /foo/bar)

                String path = RequestUtils.getServletPath(request);
                return path.substring(0, path.lastIndexOf("/"));
            }
        } else {
            return invocation.getProxy().getNamespace();
        }
    }
}