FileSystemStorage.java

package com.smash.revolance.ui.database;

/*
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * ui-monitoring-database
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * Copyright (C) 2012 - 2014 RevoLance
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * 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/gpl-3.0.html>.
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */


import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.springframework.stereotype.Service;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.*;

/**
 * User: wsmash
 * Date: 14/09/13
 * Time: 17:36
 */
@Service
public class FileSystemStorage implements IStorage
{
    private File databaseFolder;


    public FileSystemStorage(String root)
    {
        if(root != null)
        {
            databaseFolder = new File(System.getProperty("storage.location", ""), root);
            createStorageDirectory();
        }
    }

    private void createStorageDirectory()
    {
        if ( !databaseFolder.exists() )
        {
            databaseFolder.getParentFile().mkdirs();
            databaseFolder.mkdir();
        }
    }

    @Override
    public void store(String k, String o) throws StorageException
    {
        store(k, o, false);
    }

    @Override
    public void store(String k, String o, boolean override) throws StorageException
    {
        if ( isKeyValid( k ) && (override||!isKeyUsed( k )) )
        {
            FileWriter writer = null;
            File f = new File( databaseFolder, k );
            try
            {
                f.createNewFile();
                writer = new FileWriter( f );
                writer.write( o );

                writer.close();
            }
            catch (IOException e)
            {
                throw new StorageException( "Unable to create file: " + f + " or to write data into it." );
            }
            finally
            {
                IOUtils.closeQuietly( writer );
            }
        } else
        {
            throw new StorageException( "Invalid or already used key: '" + k + "'." );
        }
    }

    @Override
    public String retrieve(String key) throws StorageException
    {
        if ( isKeyValid( key ) && isKeyUsed( key ) )
        {
            try
            {
                return FileUtils.readFileToString( new File( databaseFolder, key ), "UTF-8" );
            }
            catch (IOException e)
            {
                throw new StorageException( "Unable to retrieve stored content for key: " + key );
            }
        } else
        {
            throw new StorageException( "Invalid or unused key: " + key );
        }
    }

    @Override
    public Map<String, String> retrieveAll()
    {
        Map<String, String> filesContent = new HashMap<String, String>();
        File[] files = databaseFolder.listFiles();

        if(files != null)
        {
            for ( File file : files )
            {
                try
                {
                    filesContent.put( file.getName(), FileUtils.readFileToString( file ) );
                }
                catch (IOException e)
                {
                    //TODO: log the exception but do not prevent moving on the loop
                }
            }
        }
        return filesContent;
    }

    @Override
    public Collection<String> getKeys()
    {
        List<String> keys = new ArrayList();

        File[] files = databaseFolder.listFiles();

        if( files != null )
        {
            for ( File file : files )
            {
                keys.add( file.getName() );
            }
        }

        return keys;

    }

    @Override
    public boolean isKeyUsed(String key)
    {
        return new File( databaseFolder, key ).exists();
    }

    @Override
    public boolean isKeyValid(String key)
    {
        return !key.contains( "#" ) || !key.contains( "/" ) || !key.contains( "." ) || !key.contains( "-" ) || !key.contains( "_" );
    }

    @Override
    public void clear() throws StorageException
    {
        try
        {
            FileUtils.forceDelete( databaseFolder );
            databaseFolder.mkdirs();
        }
        catch (IOException e)
        {
            throw new StorageException( "Unable to clear storage system.", e );
        }
    }

    @Override
    public File getLocation()
    {
        return databaseFolder;
    }

    @Override
    public String delete(String key) throws StorageException
    {
        if ( isKeyValid( key ) && isKeyUsed( key ) )
        {
            try
            {
                String content = retrieve( key );
                FileUtils.forceDelete( new File( databaseFolder, key ) );
                return content;
            }
            catch (IOException e)
            {
                throw new StorageException( e.getMessage() );
            }
        } else
        {
            throw new StorageException( "Invalid or unknown key: '" + key + "'." );
        }
    }
}