/**
* The Logic Lab
* @author jpk
* @since Jun 27, 2009
*/
package com.tll.server.rpc.listing;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import com.tll.common.data.ListingOp;
import com.tll.common.data.ListingPayload;
import com.tll.common.data.ListingRequest;
import com.tll.common.data.RemoteListingDefinition;
import com.tll.common.data.Status;
import com.tll.common.data.ListingPayload.ListingStatus;
import com.tll.common.model.Model;
import com.tll.common.msg.Msg.MsgAttr;
import com.tll.common.msg.Msg.MsgLevel;
import com.tll.common.search.IListingSearch;
import com.tll.criteria.Criteria;
import com.tll.criteria.InvalidCriteriaException;
import com.tll.dao.SearchResult;
import com.tll.dao.Sorting;
import com.tll.listhandler.EmptyListException;
import com.tll.listhandler.IListHandler;
import com.tll.listhandler.IListingDataProvider;
import com.tll.listhandler.ListHandlerException;
import com.tll.listhandler.ListHandlerFactory;
import com.tll.listhandler.ListHandlerType;
import com.tll.model.IEntity;
import com.tll.server.marshal.MarshalOptions;
import com.tll.server.rpc.RpcServlet;
/**
* ListingProcessor - Handles listing requests
* @author jpk
*/
final class ListingProcessor {
private final Log log = LogFactory.getLog(this.getClass());
/**
* Processes all listing requests.
* @param sessionId the unique user session id
* @param context the listing context
* @param request the listing request
* @return the resultant listing payload
*/
ListingPayload<Model> process(final String sessionId, final ListingContext context,
final ListingRequest request) {
if(context == null) throw new IllegalStateException("Null listing context");
final Status status = new Status();
if(request == null) {
status.addMsg("No listing request specified.", MsgLevel.ERROR, MsgAttr.STATUS.flag);
}
final String listingId = request == null ? null : request.getListingId();
if(listingId == null) {
status.addMsg("No listing name specified.", MsgLevel.ERROR, MsgAttr.STATUS.flag);
}
final ListingOp listingOp = request == null ? null : request.getListingOp();
if(listingOp == null) {
status.addMsg("No listing op specified.", MsgLevel.ERROR, MsgAttr.STATUS.flag);
}
ListingHandler<Model> handler = null;
ListingStatus listingStatus = null;
if(!status.hasErrors() && request != null) {
if(sessionId == null) {
status.addMsg("No session id specified.", MsgLevel.ERROR, MsgAttr.STATUS.flag);
}
else {
Integer offset = request.getOffset();
Sorting sorting = request.getSorting();
// get listing state (if cached)
final ListingState state = ListingCache.getState(sessionId, listingId);
if(state != null) {
if(log.isDebugEnabled())
log.debug("Found cached state for listing '" + listingId + "': " + state.toString());
if(offset == null) {
offset = state.getOffset();
assert offset != null;
if(log.isDebugEnabled())
log.debug("Setting offset (" + offset + ") from cache for listing:" + listingId);
}
if(sorting == null) {
sorting = state.getSorting();
assert sorting != null;
if(log.isDebugEnabled())
log.debug("Setting sorting (" + sorting.toString() + ") from cache for listing:" + listingId);
}
}
handler = ListingCache.getHandler(sessionId, listingId);
listingStatus = (handler == null ? ListingStatus.NOT_CACHED : ListingStatus.CACHED);
if(log.isDebugEnabled()) log.debug("Listing status: " + listingStatus);
try {
// acquire the listing handler
if(handler == null || listingOp == ListingOp.REFRESH) {
if(log.isDebugEnabled()) log.debug("Generating listing handler for listing: '" + listingId + "'...");
final RemoteListingDefinition<? extends IListingSearch> listingDef = request.getListingDef();
if(listingDef != null) {
final IListingSearch search = listingDef.getSearchCriteria();
if(search == null) {
throw new ListingException(listingId, "No search criteria specified.");
}
// translate client side criteria to server side criteria
final Criteria<? extends IEntity> criteria;
try {
// delegate
criteria = context.getSearchTranslator().translateListingSearchCriteria(context, search);
}
catch(final IllegalArgumentException iae) {
throw new ListingException(listingId, "Unable to translate listing search criteria: "
+ request.descriptor(), iae);
}
// resolve the listing handler data provider
final IListingDataProvider dataProvider = context.getListingDataProviderResolver().resolve(request);
// resolve the list handler type
final ListHandlerType lht = listingDef.getListHandlerType();
if(lht == null) {
throw new ListingException(listingId, "No list handler type specified.");
}
// resolve the sorting to use
sorting = (sorting == null ? listingDef.getInitialSorting() : sorting);
if(sorting == null) {
throw new ListingException(listingId, "No sorting directive specified.");
}
IListHandler<SearchResult<?>> listHandler = null;
try {
listHandler = ListHandlerFactory.create(criteria, sorting, lht, dataProvider);
}
catch(final InvalidCriteriaException e) {
throw new ListingException(listingId, "Invalid criteria: " + e.getMessage(), e);
}
catch(final EmptyListException e) {
// we proceed to allow client to still show the listing
status.addMsg(e.getMessage(), MsgLevel.WARN, MsgAttr.STATUS.flag);
}
catch(final ListHandlerException e) {
// shouldn't happen
throw new IllegalStateException("Unable to instantiate the list handler: " + e.getMessage(), e);
}
// transform to marshaling list handler
MarshalOptions mo;
try {
mo = context.getMarshalOptionsResolver().resolve(search.getEntityType());
}
catch(final IllegalArgumentException e) {
mo = MarshalOptions.NO_REFERENCES;
}
final MarshalingListHandler marshalingListHandler =
new MarshalingListHandler(listHandler, context.getMarshaler(), mo, listingDef.getPropKeys());
// instantiate the handler
handler = new ListingHandler<Model>(marshalingListHandler, listingId, listingDef.getPageSize());
}
}
// do the query related listing op
if(handler != null && listingOp != null && listingOp.isQuery()) {
if(log.isDebugEnabled())
log.debug("Performing : '" + listingOp.getName() + "' for '" + listingId + "'...");
try {
handler.query(offset.intValue(), sorting, (listingOp == ListingOp.REFRESH));
status.addMsg(listingOp.getName() + " for '" + listingId + "' successful.", MsgLevel.INFO,
MsgAttr.STATUS.flag);
}
catch(final EmptyListException e) {
// we proceed to allow client to still show the listing
status.addMsg(e.getMessage(), MsgLevel.WARN, MsgAttr.STATUS.flag);
}
catch(final ListingException e) {
throw new ListingException(listingId, "An unexpected error occurred performing listing operation: "
+ e.getMessage(), e);
}
}
}
catch(final ListingException e) {
RpcServlet.exceptionToStatus(e, status);
context.getExceptionHandler().handleException(e);
}
catch(final RuntimeException re) {
context.getExceptionHandler().handleException(re);
throw re;
}
// do caching
if(listingOp == ListingOp.CLEAR) {
// clear
if(log.isDebugEnabled()) log.debug("Clearing listing '" + listingId + "'...");
ListingCache.clearHandler(sessionId, listingId);
if(!request.getRetainStateOnClear()) {
ListingCache.clearState(sessionId, listingId);
}
listingStatus = ListingStatus.NOT_CACHED;
status.addMsg("Cleared listing data for " + listingId, MsgLevel.INFO, MsgAttr.STATUS.flag);
}
else if(listingOp == ListingOp.CLEAR_ALL) {
// clear all
if(log.isDebugEnabled()) log.debug("Clearing ALL listings...");
ListingCache.clearHandler(sessionId, listingId);
if(!request.getRetainStateOnClear()) {
ListingCache.clearAll(request.getRetainStateOnClear());
}
listingStatus = ListingStatus.NOT_CACHED;
status.addMsg("Cleared ALL listing data", MsgLevel.INFO, MsgAttr.STATUS.flag);
}
else if(handler != null && !status.hasErrors()) {
// cache listing handler
if(log.isDebugEnabled()) log.debug("[Re-]Caching listing '" + listingId + "'...");
ListingCache.storeHandler(sessionId, listingId, handler);
// cache listing state
if(log.isDebugEnabled()) log.debug("[Re-]Caching listing state '" + listingId + "'...");
ListingCache.storeState(sessionId, listingId, new ListingState(handler.getOffset(), handler.getSorting()));
listingStatus = ListingStatus.CACHED;
}
}
} // !status.hasErrors()
final ListingPayload<Model> p = new ListingPayload<Model>(status, listingId, listingStatus);
// only provide page data when it is needed at the client and there are no
// errors
if(handler != null && !status.hasErrors() && (listingOp != null && !listingOp.isClear())) {
if(log.isDebugEnabled()) log.debug("Sending page data for '" + listingId + "'...");
final List<Model> list = handler.getElements();
final Model[] arr = list == null ? new Model[0] : list.toArray(new Model[list.size()]);
p.setPageData(handler.size(), arr, handler.getOffset(), handler.getSorting());
}
return p;
}
}