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package org.atmosphere.handler;

import org.atmosphere.cpr.AtmosphereHandler;
import org.atmosphere.cpr.AtmosphereResourceEvent;
import org.atmosphere.cpr.AtmosphereServlet;
import org.atmosphere.cpr.Broadcaster;
import org.atmosphere.util.LoggerUtils;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;
import java.util.logging.Level;

/**
 * Simple {@link AtmosphereHandler} that reflect every call to
 * {@link Broadcaster#broadcast}, e.g sent the broadcasted event back to the remote client. All broadcast will be by default returned
 * as it is to the suspended {@link HttpServletResponse#getOutputStream}
 * or {@link HttpServletResponse#getWriter()}
 *
 * @author Jean-francois Arcand
 */
public abstract class AbstractReflectorAtmosphereHandler
        implements AtmosphereHandler {

    /**
     * Write the {@link AtmosphereResourceEvent#getMessage()} back to the client using
     * the {@link HttpServletResponse#getOutputStream()} or {@link HttpServletResponse#getWriter()}.
     * If a {@link org.atmosphere.cpr.Serializer} is defined, it will be invoked and the writ operation
     * will be delegated to to it.
     * 
     * By default, this method will try to use {@link HttpServletResponse#getWriter()}.
     *
     * @param event the {@link AtmosphereResourceEvent#getMessage()}
     * @throws java.io.IOException
     */
    public void onStateChange(AtmosphereResourceEvent event)
            throws IOException {

        Object o = event.getMessage();
        if (o == null || event.isCancelled()) return;

        if (event.getResource().getSerializer() != null) {
            try{
                event.getResource().getSerializer().write(event.getResource().getResponse().getOutputStream(), o);
            } catch (Throwable ex){
                LoggerUtils.getLogger().log(Level.WARNING,"Serializer exception",ex);
                throw new IOException(ex);
            }
        } else {
            boolean isUsingStream = false;
            try {
                event.getResource().getResponse().getWriter();
            } catch (IllegalStateException e) {
                isUsingStream = true;
            }

            if (o instanceof List) {
                for (String s : (List) o) {
                    if (isUsingStream) {
                        event.getResource().getResponse().getOutputStream().write(s.getBytes());
                        event.getResource().getResponse().getOutputStream().flush();
                    } else {
                        event.getResource().getResponse().getWriter().write(s);
                        event.getResource().getResponse().getWriter().flush();
                    }
                }
            } else {
                if (isUsingStream) {
                    event.getResource().getResponse().getOutputStream().write(o.toString().getBytes());
                    event.getResource().getResponse().getOutputStream().flush();
                } else {
                    event.getResource().getResponse().getWriter().write(o.toString());
                    event.getResource().getResponse().getWriter().flush();
                }
            }

            Boolean resumeOnBroadcast = (Boolean) event.getResource().getRequest().getAttribute(AtmosphereServlet.RESUME_ON_BROADCAST);
            if (resumeOnBroadcast != null && resumeOnBroadcast) {
                event.getResource().resume();
            }
        }
    }

}