/** http://www-6.ibm.com/jp/developerworks/java/011116/j_j-tomcat.html */
package ushi.svt;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

class ReplaceTextStream extends ServletOutputStream {
  private OutputStream intStream;
  private ByteArrayOutputStream baStream;
  private boolean closed = false;

  private String origText;
  private String newText;

  public ReplaceTextStream(OutputStream outStream, String searchText, String replaceText) {
    intStream = outStream;
    baStream = new ByteArrayOutputStream();
    origText = searchText;
    newText = replaceText;
  }

  public void write(int i) throws java.io.IOException {
    baStream.write(i);
  }

  public void close() throws java.io.IOException {
    if (!closed) {
      processStream();
      intStream.close();
      closed = true;
    }
  }

  public void flush() throws java.io.IOException {
    if (baStream.size() != 0) {
      if (! closed) {
        processStream();              // need to synchronize the flush!
        baStream = new ByteArrayOutputStream();
      }
    }
  }

  public void processStream() throws java.io.IOException {
    intStream.write(replaceContent(baStream.toByteArray()));
    intStream.flush();
  }

  public byte [] replaceContent(byte [] inBytes) {
    String retVal ="";
    String firstPart="";

    String tpString = new String(inBytes);
    //String srchString = (new String(inBytes)).toLowerCase();
    String srchString = new String(inBytes);

    int endBody = srchString.indexOf(origText);

    if (endBody != -1) {
      firstPart = tpString.substring(0, endBody);
      retVal = firstPart + newText + 
               tpString.substring(endBody + origText.length()); 
    }
    else {
      retVal=tpString;
    }
    return retVal.getBytes();
  }
}

class ReplaceTextWrapper extends HttpServletResponseWrapper {
  private PrintWriter tpWriter; 
  private ReplaceTextStream tpStream;

  public ReplaceTextWrapper(ServletResponse inResp, String searchText,
                            String replaceText) throws java.io.IOException { 
    super((HttpServletResponse) inResp);
    tpStream = new ReplaceTextStream(inResp.getOutputStream(), searchText, replaceText);
    tpWriter = new PrintWriter(tpStream);
  }

  public ServletOutputStream getOutputStream() throws java.io.IOException {
    return tpStream;
  }

  public PrintWriter getWriter() throws java.io.IOException {
    return tpWriter;
  }
}

public final class ReplaceTextFilter implements Filter {
  private ServletContext sc = null;
  private FilterConfig filterConfig = null;
  private String searchText = ".";
  private String replaceText = ".";

  public void doFilter(ServletRequest request, ServletResponse response,
                       FilterChain chain) throws IOException, ServletException {
    ReplaceTextWrapper myWrappedResp = new ReplaceTextWrapper( response, searchText, replaceText);
    sc.log("ReplaceTextFilterが変換を行います。");
    chain.doFilter(request, myWrappedResp);
    myWrappedResp.getOutputStream().close();
  }

  public void destroy() {
    sc.log("ReplaceTextFilterが停止しようとしています。");
  }

  public void init(FilterConfig fc) {
    String tpString;
    if (( tpString = fc.getInitParameter("search") ) != null)
      searchText = tpString;
    if (( tpString = fc.getInitParameter("replace") ) != null)
      replaceText = tpString;
    this.filterConfig = fc;
    this.sc = fc.getServletContext();
    sc.log("ReplaceTextFilterが初期化されました。");
  }
}
/* end. */