Quadcap Embeddable Server

com/quadcap/http/servlets/jsp/PageContext.java

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package com.quadcap.http.servlets.jsp;

/* Copyright 1999 - 2003 Quadcap Software.  All rights reserved.
 *
 * This software is distributed under the Quadcap Free Software License.
 * This software may be used or modified for any purpose, personal or
 * commercial.  Open Source redistributions are permitted.  Commercial
 * redistribution of larger works derived from, or works which bundle
 * this software requires a "Commercial Redistribution License"; see
 * http://www.quadcap.com/purchase.
 *
 * Redistributions qualify as "Open Source" under  one of the following terms:
 *   
 *    Redistributions are made at no charge beyond the reasonable cost of
 *    materials and delivery.
 *
 *    Redistributions are accompanied by a copy of the Source Code or by an
 *    irrevocable offer to provide a copy of the Source Code for up to three
 *    years at the cost of materials and delivery.  Such redistributions
 *    must allow further use, modification, and redistribution of the Source
 *    Code under substantially the same terms as this license.
 *
 * Redistributions of source code must retain the copyright notices as they
 * appear in each source code file, these license terms, and the
 * disclaimer/limitation of liability set forth as paragraph 6 below.
 *
 * Redistributions in binary form must reproduce this Copyright Notice,
 * these license terms, and the disclaimer/limitation of liability set
 * forth as paragraph 6 below, in the documentation and/or other materials
 * provided with the distribution.
 *
 * The Software is provided on an "AS IS" basis.  No warranty is
 * provided that the Software is free of defects, or fit for a
 * particular purpose.  
 *
 * Limitation of Liability. Quadcap Software shall not be liable
 * for any damages suffered by the Licensee or any third party resulting
 * from use of the Software.
 */

import java.io.IOException;
import java.io.PrintWriter;

import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;

import javax.servlet.RequestDispatcher;
import javax.servlet.Servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.quadcap.http.server22.HttpResponse;

import com.quadcap.util.Debug;

/**
 * The PageContext implementation.
 *
 * @author Stan Bailes
 */
public class PageContext extends javax.servlet.jsp.PageContext {
    Hashtable                   pageAttributes = null;
    Servlet                     servlet;
    HttpServletRequest          request;
    HttpServletResponse         response;
    HttpSession                 session;
    String                      errorPageURL;
    boolean                     needsSession;
    int                         bufferSize;
    boolean                     autoFlush;
    javax.servlet.jsp.JspWriter out;

    public void initialize(Servlet servlet, ServletRequest request, 
                           ServletResponse response,
                           String errorPageURL, boolean needsSession, 
                           int bufferSize, 
                           boolean autoFlush)
        throws IOException, IllegalStateException, IllegalArgumentException
    {
        this.servlet = servlet;
        this.request = (HttpServletRequest)request;
        this.response = (HttpServletResponse)response;
        this.errorPageURL = errorPageURL;
        this.needsSession = needsSession;
        this.bufferSize = bufferSize;
        this.autoFlush = autoFlush;
        this.session = null;

        if (response instanceof HttpResponse) {
            HttpResponse qresp = (HttpResponse)response;
            this.out = qresp.getJspWriter(bufferSize, autoFlush);
        } else {
            this.out = new JspWriter(response.getWriter(), bufferSize, autoFlush);
        }
    }

    public void release() {
        this.servlet = null;
        this.request = null;
        this.response = null;
        this.errorPageURL = null;
        this.session = null;
    }

    public void setAttribute(String name, Object val) {
        setAttribute(name, val, PAGE_SCOPE);
    }

    public void setAttribute(String name, Object val, int scope) {
        switch (scope) {
        case PAGE_SCOPE:
            if (pageAttributes == null) pageAttributes = new Hashtable();
            pageAttributes.put(name, val);
            break;
        case REQUEST_SCOPE:
            request.setAttribute(name, val);
            break;
        case SESSION_SCOPE:
            if (session != null) session.putValue(name, val);
            break;
        case APPLICATION_SCOPE:
            getServletContext().setAttribute(name, val);
        }           
    }

    public Object getAttribute(String name) {
        return getAttribute(name, PAGE_SCOPE);
    }

    public Object getAttribute(String name, int scope) {
        switch (scope) {
        case PAGE_SCOPE:
            if (pageAttributes != null) return pageAttributes.get(name);
            break;
        case REQUEST_SCOPE:
            return request.getAttribute(name);
        case SESSION_SCOPE:
            if (session != null) return session.getValue(name);
            break;
        case APPLICATION_SCOPE:
            return getServletContext().getAttribute(name);
        }           
        return null;
    }

    public Object findAttribute(String name) {
        Object obj = null;
        for (int i = 0; obj == null && i < 4; i++) {
            obj = getAttribute(name, i);
        }
        return obj;
    }

    public void removeAttribute(String name) {
        removeAttribute(name, PAGE_SCOPE);
    }

    public void removeAttribute(String name, int scope) {
        switch (scope) {
        case PAGE_SCOPE:
            if (pageAttributes != null) pageAttributes.remove(name);
            break;
        case REQUEST_SCOPE:
            request.setAttribute(name, "");     // XXX no remove!
            break;
        case SESSION_SCOPE:
            if (session != null) session.removeValue(name);
            break;
        case APPLICATION_SCOPE:
            getServletContext().removeAttribute(name);
        }           
    }

    public int getAttributesScope(String name) {
        int scope = 0;
        for (int i = 0; scope == 0 && i < 4; i++) {
            if (getAttribute(name, i) != null) {
                scope = i+1;
            }
        }
        return scope;
    }

    public Enumeration getAttributeNamesInScope(int scope) {
        switch (scope) {
        case PAGE_SCOPE:
            if (pageAttributes != null) return pageAttributes.keys();
            break;
        case REQUEST_SCOPE:
            return request.getAttributeNames();
        case SESSION_SCOPE:
            Vector v = new Vector();
            if (session != null) {
                String[] s = session.getValueNames();
                for (int i = 0; i < s.length; i++) v.addElement(s[i]);
            }
            return v.elements();
        case APPLICATION_SCOPE:
            return getServletContext().getAttributeNames();
        }
        return new Vector().elements();
    }

    public javax.servlet.jsp.JspWriter getOut() {
        return out;
    }

    public HttpSession getSession() {
        if (session == null) session = new JspSession(request);
        return session;
    }

    public Object getPage() {
        return servlet;
    }

    public ServletRequest getRequest() {
        return request;
    }

    public ServletResponse getResponse() {
        return response;
    }

    public Exception getException() {
        return (Exception)request.getAttribute("exception");
    }

    public ServletConfig getServletConfig() {
        return servlet.getServletConfig();
    }

    public ServletContext getServletContext() {
        return getServletConfig().getServletContext();
    }

    final String relativize(String url) throws ServletException {
        if (url.charAt(0) != '/') {
            String p = request.getServletPath();
            int idx = p.lastIndexOf('/');
            if (idx >= 0) {
                url = p.substring(0, idx) + "/" + url;
            }
        }
        return url;
    }

    public void forward(String url) throws ServletException, IOException {
        url = relativize(url);
        RequestDispatcher rd = getServletContext().getRequestDispatcher(url);
        out.clearBuffer();
        rd.forward(request, response);
    }

    public void include(String url) throws ServletException, IOException {
        url = relativize(url);
        RequestDispatcher rd = getServletContext().getRequestDispatcher(url);
        rd.include(request, response);
    }

    public void handleFinally() throws IOException {
        if (autoFlush) {
            out.flush();
        }
    }

    public void handlePageException(Exception e) 
        throws ServletException, IOException 
    {
        if (errorPageURL == null) {
            if (Trace.level() > 1) {
                Debug.print(e);
            }
            response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            PrintWriter w = response.getWriter();
            w.println("<html><head><title>");
            w.println(e.toString());
            w.println("</title></head><body>");
            w.println("<pre>");
            e.printStackTrace(w);
            w.println("</pre></body></html>");
            w.flush();
        } else {
            request.setAttribute("exception", e);
            forward(errorPageURL);
        }
    }
}