001// Copyright 2005 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007//     http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry.services.impl;
016
017import java.io.IOException;
018import java.io.UnsupportedEncodingException;
019
020import javax.servlet.ServletException;
021import javax.servlet.http.HttpServletRequest;
022import javax.servlet.http.HttpServletResponse;
023
024import org.apache.hivemind.ApplicationRuntimeException;
025import org.apache.tapestry.services.ServletRequestServicer;
026import org.apache.tapestry.services.ServletRequestServicerFilter;
027
028/**
029 * Analyzes the incoming request to set the correct output encoding.
030 * 
031 * @author Howard M. Lewis Ship
032 * @since 4.0
033 */
034public class SetupRequestEncoding implements ServletRequestServicerFilter
035{
036    private boolean _skipSet;
037
038    private String _outputEncoding;
039
040    public void service(HttpServletRequest request, HttpServletResponse response,
041            ServletRequestServicer servicer) throws IOException, ServletException
042    {
043        if (!_skipSet)
044        {
045            String encoding = request.getCharacterEncoding();
046
047            if (encoding == null)
048                setRequestEncodingToOutputEncoding(request);
049        }
050
051        // Next in chain
052
053        servicer.service(request, response);
054    }
055
056    private void setRequestEncodingToOutputEncoding(HttpServletRequest request)
057    {
058        try
059        {
060            // We compile against the 2.3 API but allow
061            // the code to execute against the 2.2 In the
062            // later case, we can get some interesting errors.
063
064            request.setCharacterEncoding(_outputEncoding);
065        }
066        catch (UnsupportedEncodingException ex)
067        {
068            throw new ApplicationRuntimeException(
069                    ImplMessages.invalidEncoding(_outputEncoding, ex), ex);
070        }
071        catch (NoSuchMethodError ex)
072        {
073            _skipSet = true;
074        }
075        catch (AbstractMethodError ex)
076        {
077            _skipSet = true;
078        }
079    }
080
081    public void setOutputEncoding(String outputEncoding)
082    {
083        _outputEncoding = outputEncoding;
084    }
085}