EventResponseRenderer

EventResponseRenderer.java

public interface EventResponseRenderer
{
    String render(RenderEvent renderEvent);
}

EventResponseRendererImpl.java

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.PrintWriter;

import org.apache.tapestry5.SymbolConstants;
import org.apache.tapestry5.internal.EmptyEventContext;
import org.apache.tapestry5.internal.services.RequestImpl;
import org.apache.tapestry5.internal.services.ResponseImpl;
import org.apache.tapestry5.internal.services.TapestrySessionFactory;
import org.apache.tapestry5.ioc.annotations.Inject;
import org.apache.tapestry5.ioc.annotations.Symbol;
import org.apache.tapestry5.services.Ajax;
import org.apache.tapestry5.services.ComponentEventRequestHandler;
import org.apache.tapestry5.services.ComponentEventRequestParameters;
import org.apache.tapestry5.services.RequestGlobals;

public class EventResponseRendererImpl implements EventResponseRenderer
{
    @Ajax
    @Inject private ComponentEventRequestHandler ajaxHandler;
    
    @Inject private RequestGlobals requestGlobals;
    @Symbol(SymbolConstants.CHARSET)
    @Inject private String applicationCharset;
    @Inject private TapestrySessionFactory sessionFactory;
    
    @Override
    public String render(RenderEvent renderEvent)
    {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        
        final PrintWriter printWriter = new PrintWriter(out);
        
        requestGlobals.storeRequestResponse(
                new RequestImpl(requestGlobals.getHTTPServletRequest(), applicationCharset, sessionFactory),
                new ResponseImpl(requestGlobals.getHTTPServletRequest(),
                                 requestGlobals.getHTTPServletResponse())
        {
            @Override
            public PrintWriter getPrintWriter(String contentType)
                    throws IOException
            {
                return printWriter;
            }
        });
        
        try
        {
            ComponentEventRequestParameters parameters = new ComponentEventRequestParameters(
                    renderEvent.getPageName(),
                    renderEvent.getPageName(),
                    renderEvent.getNestedComponentId(),
                    RenderEvent.RENDER_EVENT_TYPE,
                    new EmptyEventContext(),
                    new RenderEventContext(renderEvent.getEventArgs()));
            
            ajaxHandler.handle(parameters);
            
            return new String(out.toByteArray(), applicationCharset);
        }
        catch (IOException e)
        {
            throw new RuntimeException(e);
        }
        
    }
}

RenderEvent.java

public class RenderEvent
{
    public static final String RENDER_EVENT_TYPE = "Render";
    
    private String pageName;
    private String nestedComponentId;
    private Object[] eventArgs;
    
    public RenderEvent(String pageName, String nestedComponentId, Object... eventArgs)
    {
        this.pageName = pageName;
        this.nestedComponentId = nestedComponentId;
        this.eventArgs = eventArgs;
    }
    
    public String getPageName()
    {
        return pageName;
    }
    
    public String getNestedComponentId()
    {
        return nestedComponentId;
    }
    
    public Object[] getEventArgs()
    {
        return eventArgs;
    }
}

RenderEventContext.java

import org.apache.tapestry5.EventContext;

public class RenderEventContext implements EventContext
{
    private Object[] args;

    public RenderEventContext(Object... args)
    {
        this.args = args != null ? args : new Object[0];
    }

    @Override
    public int getCount()
    {
        return args.length;
    }

    @SuppressWarnings("unchecked")
    @Override
    public <T> T get(Class<T> desiredType, int index)
    {
        if (!desiredType.isAssignableFrom(args[index].getClass()))
        {
            throw new IllegalArgumentException("Argument at index "
                            + index + " expected to be of class "
                            + desiredType.getName() + ", but was "
                            + args[index].getClass());
        }
        return (T) args[index];
    }

    @Override
    public String[] toStrings()
    {
        //  Not used
        return null;
    }
    
}