com.redhat.lightblue.mongo.crud.MongoSequenceSupport Maven / Gradle / Ivy

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/*
 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 .
 */
package com.redhat.lightblue.mongo.crud;

import java.util.Properties;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.mongodb.DB;
import com.mongodb.DBCollection;

import com.redhat.lightblue.metadata.ValueGenerator;
import com.redhat.lightblue.mongo.common.MongoDataStore;
import com.redhat.lightblue.metadata.EntityMetadata;

import com.redhat.lightblue.util.Error;
import com.redhat.lightblue.extensions.valuegenerator.ValueGeneratorSupport;

/**
 * This class performs the interface adaptation between MongoSequence and
 * ValueGeneratorSupport. When a value generator is called from the mediator,
 * this translates that call to MongoSequence APIs.
 *
 * The mongo sequence support recognizes these properties in the value
 * generator:
 *
 * 
 *
 * name: Name of the sequence. Required parameter. Each unique name
 * corresponds to a document in the sequences collection.
 *
 * collection: Optional parameter, if ommitted, "sequences" is assumed.
 * Gives the collection name to store the document for this sequence.
 *
 * initialValue: Optional parameter, if ommitted, 1 is assumed. Gives the
 * initial value of the sequence.
 *
 * increment: Optional parameter, if ommitted, 1 is assumed. Gives the
 * increment value of the sequence.

 *
 * 
 */
public class MongoSequenceSupport implements ValueGeneratorSupport {

    private static final Logger LOGGER = LoggerFactory.getLogger(MongoSequenceSupport.class);

    private final MongoCRUDController controller;

    public static final String DEFAULT_COLLECTION_NAME = "sequences";

    public static final String PROP_NAME = "name";
    public static final String PROP_COLLECTION = "collection";
    public static final String PROP_INITIAL_VALUE = "initialValue";
    public static final String PROP_INCREMENT = "increment";

    private static final ValueGenerator.ValueGeneratorType[] TYPES = {ValueGenerator.ValueGeneratorType.IntSequence};

    public MongoSequenceSupport(MongoCRUDController controller) {
        this.controller = controller;
    }

    @Override
    public ValueGenerator.ValueGeneratorType[] getSupportedGeneratorTypes() {
        return TYPES;
    }

    @Override
    public Object generateValue(EntityMetadata md, ValueGenerator generator) {
        Properties p = generator.getProperties();
        // We expect to see at least a name for the generator
        String name = p.getProperty(PROP_NAME);
        if (name == null) {
            throw Error.get(MongoCrudConstants.ERR_NO_SEQUENCE_NAME);
        }
        String collection = p.getProperty(PROP_COLLECTION);
        if (collection == null) {
            collection = DEFAULT_COLLECTION_NAME;
        }
        String initialValueStr = p.getProperty(PROP_INITIAL_VALUE);
        long initialValue;
        if (initialValueStr == null) {
            initialValue = 1;
        } else {
            initialValue = Long.valueOf(initialValueStr).longValue();
        }
        String incrementStr = p.getProperty(PROP_INCREMENT);
        long increment;
        if (incrementStr == null) {
            increment = 1;
        } else {
            increment = Long.valueOf(incrementStr).longValue();
        }
        DB db = controller.getDbResolver().get((MongoDataStore) md.getDataStore());
        DBCollection coll = db.getCollection(collection);
        MongoSequenceGenerator gen = new MongoSequenceGenerator(coll);
        return gen.getNextSequenceValue(name, initialValue, increment);
    }
}