Java tutorial
/* Copyright 2013 Red Hat, Inc. and/or its affiliates. This file is part of lightblue. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ package com.redhat.lightblue.crud.mongo; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.mongodb.DBCollection; import com.mongodb.DBObject; import com.mongodb.DBCursor; import com.mongodb.BasicDBObject; import com.mongodb.WriteResult; import com.mongodb.WriteConcern; import com.redhat.lightblue.crud.CRUDDeleteResponse; import com.redhat.lightblue.crud.CRUDOperationContext; import com.redhat.lightblue.crud.DocCtx; import com.redhat.lightblue.crud.Operation; import com.redhat.lightblue.mongo.hystrix.FindCommand; import com.redhat.lightblue.mongo.hystrix.RemoveCommand; /** * Iterates the result set and deleted documents one by one */ public class IterateDeleter implements DocDeleter { private static final Logger LOGGER = LoggerFactory.getLogger(IterateDeleter.class); private final Translator translator; public IterateDeleter(Translator translator) { this.translator = translator; } @Override public void delete(CRUDOperationContext ctx, DBCollection collection, DBObject mongoQuery, CRUDDeleteResponse response) { LOGGER.debug("Computing the result set for {}", mongoQuery); DBCursor cursor = null; int docIndex = 0; int numDeleted = 0; try { // Find docs cursor = new FindCommand(null, collection, mongoQuery, null).execute(); LOGGER.debug("Found {} documents", cursor.count()); // read-delet while (cursor.hasNext()) { DBObject document = cursor.next(); LOGGER.debug("Retrieved doc {}", docIndex); Object id = document.get(MongoCRUDController.ID_STR); DocCtx doc = ctx.addDocument(translator.toJson(document)); doc.setOriginalDocument(doc); WriteResult result = new RemoveCommand(null, collection, new BasicDBObject("_id", id), WriteConcern.SAFE).execute(); if (result.getN() == 1) { numDeleted++; doc.setOperationPerformed(Operation.DELETE); } docIndex++; } } finally { if (cursor != null) { cursor.close(); } } response.setNumDeleted(numDeleted); } }