packagecoreservlets;

importjava.io.*;

importjavax.servlet.*;

importjavax.servlet.http.*;

importjava.net.*;

publicclassSearchEnginesextendsHttpServlet{

publicvoiddoGet(HttpServletRequestrequest,

HttpServletResponseresponse)

throwsServletException,IOException{

StringsearchString=request.getParameter("searchString");

if((searchString==null)

(searchString.length()==0)){

reportProblem(response,"Missingsearchstring.");

return;

}

//TheURLEncoderchangesspacesto"+"signsandother

//non-alphanumericcharactersto"%XY",whereXYisthe

//hexvalueoftheASCII(orISOLatin-1)character.

//BrowsersalwaysURL-encodeformvalues,sothe

//getParametermethoddecodesautomatically.Butsince

//we"rejustpassingthisontoanotherserver,weneedto

//re-encodeit.

searchString=URLEncoder.encode(searchString);

StringnumResults=request.getParameter("numResults");

if((numResults==null)

(numResults.equals("0"))

(numResults.length()==0)){

numResults="10";

}

StringsearchEngine=

request.getParameter("searchEngine");

if(searchEngine==null){

reportProblem(response,"Missingsearchenginename.");

return;

}

SearchSpec[]commonSpecs=SearchSpec.getCommonSpecs();

for(inti=0;i<commonSpecs.length;i++){

SearchSpecsearchSpec=commonSpecs[i];

if(searchSpec.getName().equals(searchEngine)){

Stringurl=

searchSpec.makeURL(searchString,numResults);

response.sendRedirect(url);

return;

}

}

reportProblem(response,"Unrecognizedsearchengine.");

}

privatevoidreportProblem(HttpServletResponseresponse,

Stringmessage)

throwsIOException{

response.sendError(response.SC_NOT_FOUND,

"<H2>"+message+"</H2>");

}

publicvoiddoPost(HttpServletRequestrequest,

HttpServletResponseresponse)

throwsServletException,IOException{

doGet(request,response);

}

}