org.ploin.web.faces.core.BackNavigationHandler.java Source code

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Here is the source code for org.ploin.web.faces.core.BackNavigationHandler.java

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/**
 * Copyright [2008] [PLOIN GmbH -> http://www.ploin.de]
 * 
 * Licensed 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.ploin.web.faces.core;

import com.sun.faces.application.NavigationHandlerImpl;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import javax.faces.application.ViewHandler;
import javax.faces.component.UIViewRoot;
import javax.faces.context.FacesContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.io.Serializable;
import java.util.Stack;

/**
 * This Class handle the navigation
 * <p/>
 * $LastChangedBy: r.reiz $<br>
 * $Revision: 126 $<br>
 * $Date: 2010-05-22 18:46:29 +0200 (Sat, 22 May 2010) $<br>
 */
public class BackNavigationHandler extends NavigationHandlerImpl implements Serializable {

    private static final long serialVersionUID = 4582130084496276001L;
    private static Log log = LogFactory.getLog(BackNavigationHandler.class);

    public BackNavigationHandler() {
        log.debug("construct BackNavigationHandler");
    }

    @Override
    public void handleNavigation(FacesContext facesContext, String fromAction, String outcome) {
        String viewId = facesContext.getViewRoot().getViewId();
        log.debug("outcome " + outcome);

        HttpServletRequest request = (HttpServletRequest) facesContext.getExternalContext().getRequest();
        HttpSession session = request.getSession();
        Stack<String> lastViewIds = (Stack<String>) session.getAttribute("lastViewIds");
        if (lastViewIds == null)
            lastViewIds = new Stack<String>();

        session.setAttribute("ploinFacesFromViewId", viewId);

        if (outcome != null) {
            if ("back".equals(outcome)) {
                String lastViewId = lastViewIds.pop();
                navigateToViewId(facesContext, lastViewId);
                return;
            } else if ("backback".equals(outcome)) {
                lastViewIds.pop();
                String lastViewId = lastViewIds.pop();
                navigateToViewId(facesContext, lastViewId);
                return;
            } else if ("backbackback".equals(outcome)) {
                lastViewIds.pop();
                lastViewIds.pop();
                String lastViewId = lastViewIds.pop();
                navigateToViewId(facesContext, lastViewId);
                return;
            } else if ("back4".equals(outcome)) {
                lastViewIds.pop();
                lastViewIds.pop();
                lastViewIds.pop();
                String lastViewId = lastViewIds.pop();
                navigateToViewId(facesContext, lastViewId);
                return;
            } else if ("back5".equals(outcome)) {
                lastViewIds.pop();
                lastViewIds.pop();
                lastViewIds.pop();
                lastViewIds.pop();
                String lastViewId = lastViewIds.pop();
                navigateToViewId(facesContext, lastViewId);
                return;
            } else {

                String out = outcome;
                if (out == null)
                    out = "";
                out = out.replaceFirst("->", "");

                if (lastViewIds.isEmpty())
                    lastViewIds.push(viewId);
                else if (!lastViewIds.peek().equals(viewId) && !out.equals(viewId))
                    lastViewIds.push(viewId);

                if (lastViewIds.size() > 10)
                    lastViewIds.remove(0);

                if (outcome.startsWith("->")) {
                    outcome = outcome.replaceFirst("->", "");
                    navigateToViewId(facesContext, outcome);
                    return;
                }
            }
        }
        session.setAttribute("lastViewIds", lastViewIds);
        super.handleNavigation(facesContext, fromAction, outcome);
        log.debug("after navigation");
    }

    private void navigateToViewId(FacesContext facesContext, final String lastViewId) {
        log.debug("navigateToViewId to " + lastViewId);
        ViewHandler viewHandler = facesContext.getApplication().getViewHandler();
        UIViewRoot viewRoot = viewHandler.createView(facesContext, lastViewId);
        facesContext.setViewRoot(viewRoot);
        facesContext.renderResponse();
    }

}