org.emonocot.harvest.common.DirectoryReader.java Source code

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Here is the source code for org.emonocot.harvest.common.DirectoryReader.java

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/*
 * This is eMonocot, a global online biodiversity information resource.
 *
 * Copyright  20112015 The Board of Trustees of the Royal Botanic Gardens, Kew and The University of Oxford
 *
 * eMonocot is free software: you can redistribute it and/or modify it under the terms of the
 * GNU Affero General Public License as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 *
 * eMonocot 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 Affero General Public License for more details.
 *
 * The complete text of the GNU Affero General Public License is in the source repository as the file
 * COPYING.  It is also available from <http://www.gnu.org/licenses/>.
 */
package org.emonocot.harvest.common;

import java.io.File;
import java.io.FileFilter;
import java.util.Arrays;

import org.apache.commons.io.comparator.NameFileComparator;
import org.apache.commons.io.filefilter.FileFilterUtils;
import org.springframework.batch.item.ExecutionContext;
import org.springframework.batch.item.ItemReader;
import org.springframework.batch.item.ItemStream;
import org.springframework.batch.item.ItemStreamException;

public class DirectoryReader implements ItemReader<File>, ItemStream {

    private File[] files;

    private int currentCount;

    private String key = "file.in.directory.count";

    private String directoryName;

    @Override
    public void open(ExecutionContext executionContext) throws ItemStreamException {
        File directory = new File(directoryName);
        if (directory.isDirectory()) {
            this.files = directory.listFiles((FileFilter) FileFilterUtils.fileFileFilter());
            if (files.length > 1) {
                Arrays.sort(files, new NameFileComparator());
            }
        } else {
            throw new IllegalArgumentException(directoryName + " is not a directory");
        }
        currentCount = executionContext.getInt(key, 0);
    }

    @Override
    public void update(ExecutionContext executionContext) throws ItemStreamException {
        executionContext.putInt(key, currentCount);
    }

    @Override
    public void close() throws ItemStreamException {
    }

    @Override
    public File read() throws Exception {
        int index = ++currentCount - 1;
        if (index == files.length) {
            return null;
        }
        return files[index];
    }

    public void setDirectoryName(String directoryName) {
        this.directoryName = directoryName;
    }
}