pagecontextimpl.java

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                    throw (IOException)ex;
                } else {
                    throw (ServletException)ex;
                }
            }
        } else {
            doInclude(relativeUrlPath, flush);
        }
    }

    private void doInclude(String relativeUrlPath, boolean flush)
	        throws ServletException, IOException {
        JspRuntimeLibrary.include(request, response, relativeUrlPath, out,
				  flush);
    }

    public VariableResolver getVariableResolver() {
	return this;
    }

    public void forward(final String relativeUrlPath)
        throws ServletException, IOException {
        if (SecurityUtil.isPackageProtectionEnabled()){
            try{
                AccessController.doPrivileged(new PrivilegedExceptionAction(){
                    public Object run() throws Exception{
                        doForward(relativeUrlPath);
                        return null;
                    }
                });
            } catch (PrivilegedActionException e){
                Exception ex =  e.getException();
                if (ex instanceof IOException){
                    throw (IOException)ex;
                } else {
                    throw (ServletException)ex;
                }
            }
        } else {
            doForward(relativeUrlPath);
        }
    }

    private void doForward(String relativeUrlPath)
        throws ServletException, IOException{

        // JSP.4.5 If the buffer was flushed, throw IllegalStateException
        try {
            out.clear();
        } catch (IOException ex) {
            IllegalStateException ise =
                new IllegalStateException(Localizer.getMessage(
                            "jsp.error.attempt_to_clear_flushed_buffer"));
            ise.initCause(ex);
            throw ise;
        }

        // Make sure that the response object is not the wrapper for include
        while (response instanceof ServletResponseWrapperInclude) {
            response = ((ServletResponseWrapperInclude)response).getResponse();
        }

        final String path = getAbsolutePathRelativeToContext(relativeUrlPath);
        String includeUri
            = (String) request.getAttribute(Constants.INC_SERVLET_PATH);
            
        final ServletResponse fresponse = response;
        final ServletRequest frequest = request;
            
        if (includeUri != null)
            request.removeAttribute(Constants.INC_SERVLET_PATH);
        try {
            context.getRequestDispatcher(path).forward(request, response);
        } finally {
            if (includeUri != null)
                request.setAttribute(Constants.INC_SERVLET_PATH, includeUri);
            request.setAttribute(Constants.FORWARD_SEEN, "true");
        }
    }

    public BodyContent pushBody() {
	return (BodyContent) pushBody(null);
    }

    public JspWriter pushBody(Writer writer) {
        depth++;
        if (depth >= outs.length) {
            BodyContentImpl[] newOuts = new BodyContentImpl[depth + 1];
            for (int i=0; i<outs.length; i++) {
                newOuts[i] = outs[i];
            }
            newOuts[depth] = new BodyContentImpl(out);
            outs = newOuts;
        }

	outs[depth].setWriter(writer);
        out = outs[depth];

	// Update the value of the "out" attribute in the page scope
	// attribute namespace of this PageContext
	setAttribute(OUT, out);

        return outs[depth];
    }

    public JspWriter popBody() {
        depth--;
        if (depth >= 0) {
            out = outs[depth];
        } else {
            out = baseOut;
        }

	// Update the value of the "out" attribute in the page scope
	// attribute namespace of this PageContext
	setAttribute(OUT, out);

        return out;
    }

    /**
     * Provides programmatic access to the ExpressionEvaluator.
     * The JSP Container must return a valid instance of an
     * ExpressionEvaluator that can parse EL expressions.
     */
    public ExpressionEvaluator getExpressionEvaluator() {
        return elExprEval;
    }

    public void handlePageException(Exception ex)
        throws IOException, ServletException
    {
        // Should never be called since handleException() called with a
        // Throwable in the generated servlet.
        handlePageException((Throwable) ex);
    }

    public void handlePageException(final Throwable t)
        throws IOException, ServletException
    {
        if (t == null)
            throw new NullPointerException("null Throwable");

        if (SecurityUtil.isPackageProtectionEnabled()){
            try{
                AccessController.doPrivileged(new PrivilegedExceptionAction(){
                    public Object run() throws Exception{
                        doHandlePageException(t);
                        return null;
                    }
                });
            } catch (PrivilegedActionException e){
                Exception ex =  e.getException();
                if (ex instanceof IOException){
                    throw (IOException)ex;
                } else {
                    throw (ServletException)ex;
                }
            }
        } else {
            doHandlePageException(t);
        }

    }

    private void doHandlePageException(Throwable t)
        throws IOException, ServletException {

        if (errorPageURL != null && !errorPageURL.equals("")) {

            /*
             * Set request attributes.
             * Do not set the javax.servlet.error.exception attribute here
             * (instead, set in the generated servlet code for the error page)
             * in order to prevent the ErrorReportValve, which is invoked as
             * part of forwarding the request to the error page, from
             * throwing it if the response has not been committed (the response
             * will have been committed if the error page is a JSP page).
             */
            request.setAttribute("javax.servlet.jsp.jspException", t);
            request.setAttribute("javax.servlet.error.status_code",
                new Integer(HttpServletResponse.SC_INTERNAL_SERVER_ERROR));
            request.setAttribute("javax.servlet.error.request_uri",
            ((HttpServletRequest) request).getRequestURI());
            request.setAttribute("javax.servlet.error.servlet_name",
                     config.getServletName());
            try {
                forward(errorPageURL);
            } catch (IllegalStateException ise) {
                include(errorPageURL);
            }

            // The error page could be inside an include.

            Object newException = request.getAttribute("javax.servlet.error.exception");

            // t==null means the attribute was not set.
            if( (newException!= null) && (newException==t) ) {
                request.removeAttribute("javax.servlet.error.exception");
            }

            // now clear the error code - to prevent double handling.
            request.removeAttribute("javax.servlet.error.status_code");
            request.removeAttribute("javax.servlet.error.request_uri");
            request.removeAttribute("javax.servlet.error.status_code");
            request.removeAttribute("javax.servlet.jsp.jspException");

        } else {
            // Otherwise throw the exception wrapped inside a ServletException.
            // Set the exception as the root cause in the ServletException
            // to get a stack trace for the real problem
            if (t instanceof IOException) throw (IOException)t;
            if (t instanceof ServletException) throw (ServletException)t;
            if (t instanceof RuntimeException) throw (RuntimeException)t;

            Throwable rootCause = null;
            if (t instanceof JspException) {
                rootCause = ((JspException) t).getRootCause();
            } else if (t instanceof ELException) {
                rootCause = ((ELException) t).getRootCause();
            }

            if (rootCause != null) {
                throw new ServletException(t.getClass().getName() + ": " + 
                                           t.getMessage(), rootCause);
            }
                 
            throw new ServletException(t);
        }
    }

    /**
     * VariableResolver interface
     */
    public Object resolveVariable(String pName) throws ELException {
	return variableResolver.resolveVariable(pName);
    }

    private static String XmlEscape(String s) {
        if (s == null) return null;
        StringBuffer sb = new StringBuffer();
        for(int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (c == '<') {
                sb.append("&lt;");
            } else if (c == '>') {
                sb.append("&gt;");
            } else if (c == '\'') {
                sb.append("&#039;");	// &apos;
            } else if (c == '&') {
                sb.append("&amp;");
            } else if (c == '"') {
                sb.append("&#034;");	// &quot;
            } else {
                sb.append(c);
            }
        }
        return sb.toString();
    }

    /**
     * Proprietary method to evaluate EL expressions.
     * XXX - This method should go away once the EL interpreter moves
     * out of JSTL and into its own project.  For now, this is necessary
     * because the standard machinery is too slow.
     *
     * @param expression The expression to be evaluated
     * @param expectedType The expected resulting type
     * @param pageContext The page context
     * @param functionMap Maps prefix and name to Method
     * @return The result of the evaluation
     */
    public static Object proprietaryEvaluate(final String expression, 
					     final Class expectedType,
					     final PageContext pageContext,
					     final ProtectedFunctionMapper functionMap,
					     final boolean escape)
	throws ELException
    {
	Object retValue;
        if (SecurityUtil.isPackageProtectionEnabled()){
            try {
                retValue = AccessController.doPrivileged(
			new PrivilegedExceptionAction(){

                    public Object run() throws Exception{
                        return elExprEval.evaluate(expression,
						   expectedType,
						   pageContext.getVariableResolver(),
						   functionMap);
                    }
                });
            } catch (PrivilegedActionException ex) {
                Exception realEx = ex.getException();
		if (realEx instanceof ELException) {
		    throw (ELException) realEx;
		} else {
		    throw new ELException(realEx);
		}
            }
        } else {
	    retValue = elExprEval.evaluate(expression,
					   expectedType,
					   pageContext.getVariableResolver(),
					   functionMap);
        }
	if (escape) {
	    retValue = XmlEscape(retValue.toString());
	}

	return retValue;
    }

}