RealFileSystem.java

package rabbitescape.engine.util;

import static rabbitescape.engine.util.Util.*;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class RealFileSystem implements FileSystem
{
    @Override
    public boolean exists( String fileName )
    {
        return new File( fileName ).exists();
    }

    @Override
    public String[] readLines( String fileName )
        throws FileNotFoundException, IOException
    {
        List<String> ret = new ArrayList<>();

        try (
            BufferedReader reader = new BufferedReader(
                new FileReader( new File( fileName ) )
            )
        )
        {
            String line = reader.readLine();

            while ( line != null )
            {
                ret.add( line );
                line = reader.readLine();
            }

            return stringArray( ret );
        }
    }

    @Override
    public String read( String fileName )
        throws FileNotFoundException, IOException
    {
        return join( "\n", readLines( fileName ) );
    }

    @Override
    public void write( String fileName, String contents ) throws IOException
    {
        try ( FileWriter writer = new FileWriter( new File( fileName ) ) )
        {
            writer.append( contents );
        }
    }

    @Override
    public String parent( String filePath )
    {
        return new File( filePath ).getParent();
    }

    @Override
    public void mkdirs( String dirPath )
    {
        new File( dirPath ).mkdirs();
    }

    public List<String> ls( String dir, boolean recursive )
    {
        String[] content = new File( dir ).list();
        if ( null == content || 0 == content.length )
        {
            return new ArrayList<String>();
        }
        List<String> ret = Arrays.asList( content );
        if ( recursive )
        {
            List<String> retRecursive = new ArrayList<String>( ret );
            for ( String s : ret )
            {
                String subdir = dir + File.separator + s;
                List<String> more = ls( subdir, recursive );
                for ( String t : more )
                {
                    retRecursive.add( s + File.separator + t );
                }
            }
            return retRecursive;
        }
        else
        {
            return ret;
        }
    }
}