ch.qos.logback.contrib.mongodb.MongoDBAppenderBase.java Source code

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Here is the source code for ch.qos.logback.contrib.mongodb.MongoDBAppenderBase.java

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/**
 * Copyright (C) 2016, The logback-contrib developers. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.contrib.mongodb;

import ch.qos.logback.core.UnsynchronizedAppenderBase;

import com.mongodb.*;

/**
 * An abstract appender handling connection to MongoDB. Subclasses should
 * implement {@link #toMongoDocument(Object)}.
 * 
 * @author Tomasz Nurkiewicz
 * @author Christian Trutz
 * @since 0.1
 */
public abstract class MongoDBAppenderBase<E> extends UnsynchronizedAppenderBase<E> {

    // MongoDB instance
    private MongoClient mongoClient = null;

    // MongoDB collection containing logging events
    private DBCollection eventsCollection = null;

    // see also http://www.mongodb.org/display/DOCS/Connections
    private String uri = null;

    private MongoClientFactory mongoClientFactory;

    public MongoDBAppenderBase() {
        super();
        this.mongoClientFactory = new DefaultMongoClientFactory();
    }

    public MongoDBAppenderBase(MongoClientFactory factory) {
        super();
        this.mongoClientFactory = factory;
    }

    /**
     * If appender starts, create a new MongoDB connection and authenticate
     * user. A MongoDB database and collection in {@link #setUri(String)} is
     * mandatory, username and password are optional.
     */
    @Override
    public void start() {
        try {
            if (uri == null) {
                addError("Please set a non-null MongoDB URI.");
                return;
            }
            MongoClientURI mongoURI = new MongoClientURI(uri);
            String database = mongoURI.getDatabase();
            String collection = mongoURI.getCollection();
            if (database == null || collection == null) {
                addError("Error connecting to MongoDB URI: " + uri + " must contain a database and a collection."
                        + " E.g. mongodb://localhost/database.collection");
                return;
            }
            mongoClient = mongoClientFactory.createMongoClient(mongoURI);

            DB db = this.mongoClient.getDB(database);
            eventsCollection = db.getCollection(collection);
            super.start();
        } catch (Exception exception) {
            addError("Error connecting to MongoDB URI: " + uri, exception);
        }
    }

    /**
     * Inserts a new MongoDB document representing {@code eventObject} into
     * MongoDB database.
     * 
     * @param event
     *            a logging event, containing all log data
     */
    @Override
    protected void append(E event) {
        eventsCollection.insert(toMongoDocument(event));
    }

    /**
     * Creates a new MongoDB document {@link BasicDBObject} from a logging
     * event, containing all log data.
     * 
     * @param event
     *            a logging event, containing all log data
     * @return a {@link BasicDBObject} to be inserted into MongoDB
     */
    protected abstract BasicDBObject toMongoDocument(E event);

    /**
     * If appender stops, close also the MongoDB connection.
     */
    @Override
    public void stop() {
        if (mongoClient != null)
            mongoClient.close();
        super.stop();
    }

    /**
     * A {@code uri} contains all MongoDB connection data.
     * 
     * @param uri
     *            <a href="http://www.mongodb.org/display/DOCS/Connections">a
     *            MongoDB URI</a>
     */
    public void setUri(String uri) {
        this.uri = uri;
    }

}