resourceenginefilter.java

来自「ajax patterns 这是关于ajax设计模式方面的原代码」· Java 代码 · 共 66 行

/*
    Copyright 2006 Christian Gross http://www.devspace.com
    From the book Ajax Patterns and Best Practices

   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 devspace.ajax.statenavigation;
import javax.servlet.http.*;
import javax.servlet.*;
import java.io.*;

public class ResourceEngineFilter extends TriggerFilter {
    private FilterConfig _filterConfig;
   
    private Router _router;
    private String _clsRewriter;
    
    public void init(FilterConfig filterConfig) throws ServletException {
        _filterConfig = filterConfig;
        try {
            _router = (Router)ResourceEngineFilter.class.getClassLoader().loadClass(
                filterConfig.getInitParameter("router")).newInstance();
            _router.setConfiguration( filterConfig);
            _clsRewriter = filterConfig.getInitParameter("rewriter");
        }
        catch (Exception e) {
            throw new ServletException( "Could not instantiate _router", e);
        }
        
    }
    public Object initializeRequest() {
        return null;
    }
    public void destroyRequest( Object objData) {
        
    }
    
    public boolean isTrigger( Object objData, HttpServletRequest request, HttpServletResponse response) {
        if (_router.IsResource( request)) {
            return true;
        }
        return false;
    }
    public void runFilter( Object objData, HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException {
        Rewriter rewriter;
        try {
            rewriter = (Rewriter)ResourceEngineFilter.class.getClassLoader().loadClass(_clsRewriter).newInstance();
        }
        catch( Exception ex) {
            return;
        }
        _router.WriteRedirection( rewriter, request);
    }
}