IntegerGenerator.java

/*
 * Copyright 2014 Thiago da Silva Gonzaga <thiagosg@sjrp.unesp.br>.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.arquivolivre.mongocom.utils;

import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBObject;

/**
 *
 * @author Thiago da Silva Gonzaga <thiagosg@sjrp.unesp.br>
 */
public class IntegerGenerator implements Generator {

    @Override
    public Integer generateValue(Class parent, DB db) {
        DBCollection collection = db.getCollection("values_" + parent.getSimpleName());
        DBObject o = collection.findOne();
        int value = 0;
        if (o != null) {
            value = (int) o.get("generatedValue");
        } else {
            o = new BasicDBObject("generatedValue", value);
        }
        o.put("generatedValue", ++value);
        collection.save(o);
        return value;
    }

}