DxDirectoryStream.java

/*
 * Copyright (c) 2013, the authors.
 *
 *   This file is part of 'DXFS'.
 *
 *   DXFS 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.
 *
 *   DXFS 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 DXFS.  If not, see <http://www.gnu.org/licenses/>.
 */

package nextflow.fs.dx;

import java.io.IOException;
import java.nio.file.DirectoryIteratorException;
import java.nio.file.DirectoryStream;
import java.nio.file.Path;
import java.util.Iterator;

/**
 * Stream the content of teh specified path
 *
 * @see DirectoryStream
 * @author Paolo Di Tommaso <paolo.ditommaso@gmail.com>
 *
 */
public class DxDirectoryStream implements DirectoryStream<Path> {

    private final Filter<? super Path> filter;
    private DxPath path;
    private Iterator<DxPath> target;


    public DxDirectoryStream( DxPath path, Filter<? super Path> filter ) throws IOException {
        this.path = path;
        this.filter = filter;
        this.target = path.getFileSystem().folderIterator(path);
    }


    @Override
    public Iterator<Path> iterator()  {


        return new Iterator<Path>() {

            Path nextValue = findNext(target);

            @Override
            public boolean hasNext() {
                return nextValue != null;
            }

            @Override
            public Path next() {
                Path result = nextValue;
                nextValue = findNext(target);
                return result;
            }

            @Override
            public void remove() {
                throw new UnsupportedOperationException();
            }
        };

    }

    private Path findNext(Iterator<DxPath> it)  {
        while( it.hasNext() ) {
            Path item = it.next();
            try {
                if( filter == null || filter.accept(item) ) {
                    return item;
                }
            }
            catch( IOException e ) {
                throw new DirectoryIteratorException(e);
            }
        }

        return null;
    }

    @Override
    public void close() throws IOException {
        // nothing to do
    }




}