cfel.service.DatabaseServive.java Source code

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Here is the source code for cfel.service.DatabaseServive.java

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/*******************************************************************************
 * Copyright (c) 2014 IBM Corporation and Others
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   IBM Corporation - initial API and implementation
 *******************************************************************************/

package cfel.service;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.UnknownHostException;
import java.util.Set;

import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.MongoClient;
import com.mongodb.gridfs.GridFS;
import com.mongodb.gridfs.GridFSDBFile;
import com.mongodb.gridfs.GridFSInputFile;

public class DatabaseServive {
    private static DatabaseServive sDS;

    private DB mDB = null;
    private GridFS mFS = null;

    public static synchronized DatabaseServive getInstance() {
        if (sDS == null) {
            sDS = new DatabaseServive(Config.MONGO_HOST, Config.ALBUM_DB);
        }
        return sDS;
    }

    public DatabaseServive(String host, String dbName) {
        try {
            mFS = new GridFS(mDB = new MongoClient(host).getDB(dbName));
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
    }

    public Set<String> getCollectionNames() {
        return mDB != null ? mDB.getCollectionNames() : null;
    }

    public DBCollection getCollection(String collectionName) {
        return mDB != null && collectionName != null ? mDB.getCollection(collectionName) : null;
    }

    /*
     * GridFS services
     */
    public DBCursor getFileList() {
        return mFS != null ? mFS.getFileList() : null;
    }

    public GridFSDBFile getFile(String id) {
        return mFS != null ? mFS.findOne(id) : null;
    }

    public boolean saveFile(String id, InputStream is, String contentType) throws IOException {
        OutputStream os = getFileOutputStream(id, contentType);
        if (os != null) {
            try {
                byte data[] = new byte[4096];
                int len = 0;
                while ((len = is.read(data, 0, data.length)) > 0) {
                    os.write(data, 0, len);
                }
                return true;
            } finally {
                os.close();
            }
        }
        return false;
    }

    public OutputStream getFileOutputStream(String id, String contentType) {
        if (mFS != null) {
            try {
                deleteFile(id);
                GridFSInputFile dbFile = mFS.createFile(id);
                if (contentType != null) {
                    dbFile.setContentType(contentType);
                }
                return dbFile.getOutputStream();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    public boolean deleteFile(String id) {
        if (getFile(id) == null) {
            return false;
        }
        mFS.remove(id);
        return true;
    }

    public boolean readFile(String id, OutputStream os) throws IOException {
        GridFSDBFile dbFile = getFile(id);
        if (dbFile == null) {
            return false;
        }
        InputStream is = null;
        try {
            is = dbFile.getInputStream();
            byte data[] = new byte[4096];
            int len = 0;
            while ((len = is.read(data, 0, data.length)) > 0) {
                os.write(data, 0, len);
            }
            return true;
        } finally {
            if (is != null) {
                is.close();
            }
        }
    }
}