package ecologylab.oodss.messages;

import java.util.Collection;

import ecologylab.collections.Scope;
import ecologylab.net.ParsedURL;
import ecologylab.serialization.annotations.simpl_inherit;

/**
 * Abstract base class for ecologylab.oodss DCF request messages.
 * 
 * @author blake
 * @author andruid
 */
@simpl_inherit public abstract class MultiRequestMessage<S extends Scope> extends ServiceMessage<S>
{
	public MultiRequestMessage()
	{
		super();
	}
	
	/**
	 * Perform the service associated with the request, using the supplied context as needed.
	 * 
	 * @param localScope
	 *           Context to perform it in/with.
	 * @return Response to pass back to the (remote) caller.
	 */
	public abstract Collection<ResponseMessage> performService(S clientSessionScope);

	/**
	 * Indicates whether or not this type of message may be ignored by the server, if the server becomes backed-up. For
	 * example, a RequestMessage subclass that simply requests the server's current state may be ignored if a more recent
	 * copy of one has arrived later.
	 * 
	 * By default, RequestMessages are not disposable; this method should be overriden if they are to be.
	 * 
	 * @return false.
	 */
	public boolean isDisposable()
	{
		return false;
	}
	
	/**
	 * A URL can be provided, indicating the response should be accomplished with HTTP redirect.
	 * Used when browser security is an issue.
	 * <p/>
	 * This is the redirect URL for response when processing is successful.
	 * 
	 * @param clientSessionScope	Can be used to generate HTTP GET style arguments in the redirect URL.
	 * 
	 * @return		null in this the base class case.
	 */
	public ParsedURL okRedirectUrl(S clientSessionScope)
	{
		return null;
	}
	
	/**
	 * A URL can be provided, indicating the response should be accomplished with HTTP redirect.
	 * Used when browser security is an issue.
	 * <p/>
	 * This is the redirect URL for response when processing results in an error.
	 * 
	 * @param clientSessionScope	Can be used to generate HTTP GET style arguments in the redirect URL.
	 * 
	 * @return		null in this the base class case.
	 */
	public ParsedURL errorRedirectUrl(S clientSessionScope)
	{
		return null;
	}

}