source: ether_ndacc/trunk/common/implementation/com/ether/WebHelper.java @ 204

package com.ether;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.security.InvalidParameterException;

public final class WebHelper
{
    private WebHelper()
    {
    }

    @NotNull
    public static String getRequestParameter(@NotNull final HttpServletRequest httpServletRequest, @Nullable final String parameterName, @Nullable final String defaultParameterValue, final boolean canBeNull )
        throws InvalidParameterException
    {
        String parameterValue;
        if(null == parameterName)
                parameterValue = defaultParameterValue;
        
        parameterValue = httpServletRequest.getParameter( parameterName );

        if( parameterValue == null )
            parameterValue = defaultParameterValue;

        if( !canBeNull && parameterValue == null )
            throw new InvalidParameterException( parameterName );

        return parameterValue;
    }

    public static void writeJsonToResponse( @NotNull final HttpServletResponse httpServletResponse, @NotNull final String data )
            throws IOException
    {
        httpServletResponse.setCharacterEncoding( UTF8Charset.getEncoding() );
        httpServletResponse.setContentType( CONTENT_TYPE_TEXT_JSON );

        final PrintWriter writer = httpServletResponse.getWriter();

        writer.write( JSON_TAG_BEGIN );
        writer.write( data );
        writer.write( JSON_TAG_END );
    }

    public static void displayError( @NotNull final HttpServletResponse response, @Nullable final String methodName )
        throws EtherException
    {           
        try {
                response.setStatus(HttpServletResponse.SC_NOT_IMPLEMENTED);
                response.setCharacterEncoding(UTF8Charset.getEncoding());
                response.setContentType("text/plain;charset="+ UTF8Charset.getEncoding());
                final ServletOutputStream outputStream = response.getOutputStream();
                outputStream.print("error.method_not_implemented : " + methodName+ " is not implemented.");
                outputStream.flush();
                outputStream.close();
        } catch (IOException e) {
                throw new EtherException( EtherException.EtherCode.IO_EXCEPTION_ERROR_TO_GET_OUTPUTSTREAM, e);
        }
    }

    /**
     * This method returns the part of URL after the servlet without the part "language"
     *
     * @param request
     * @return
     */
    @NotNull
    public static String getUrlToRecall( @Nullable final HttpServletRequest request )
    {
        if( null == request )
            return "";
        else
        {
            // TODO : récupérer cette chaine directement à partir du bean localeChangeInterceptor du servlet-context.xml
            final String localeChangeInterceptorParam = "language";

            final String queryString = request.getQueryString();
            if( !queryString.contains( localeChangeInterceptorParam ) )
                return queryString;
            else
            {
                final String[] strings = queryString.split( '&' + localeChangeInterceptorParam );
                final int indexNextParam = strings[1].indexOf( "&" );
                if( -1 != indexNextParam )
                    return strings[0] + strings[1].substring( indexNextParam );
                else
                    return strings[0];
            }
        }
    }

    private static final Log LOGGER = LogFactory.getLog( WebHelper.class );
    
    private static final String CONTENT_TYPE_TEXT_JSON = "text/javascript;charset=" + UTF8Charset.getEncoding();
    private static final char JSON_TAG_BEGIN = ' ' ;  // '(';
    private static final char JSON_TAG_END = ' ';     // ')';
}