opennlp.tools.formats.DirectorySampleStream.java Source code

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Here is the source code for opennlp.tools.formats.DirectorySampleStream.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package opennlp.tools.formats;

import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Stack;

import opennlp.tools.util.ObjectStream;

/**
 * The directory sample stream allows for creating a stream
 * from a directory listing of files.
 */
public class DirectorySampleStream implements ObjectStream<File> {

    private final List<File> inputDirectories;

    private final boolean recursive;

    private final FileFilter fileFilter;

    private Stack<File> directories = new Stack<>();

    private Stack<File> textFiles = new Stack<>();

    /**
     * Creates a new directory sample stream.
     * @param dirs The directories to read.
     * @param fileFilter The {@link FileFilter filter} to apply while enumerating files.
     * @param recursive Enables or disables recursive file listing.
     */
    public DirectorySampleStream(File[] dirs, FileFilter fileFilter, boolean recursive) {
        this.fileFilter = fileFilter;
        this.recursive = recursive;

        List<File> inputDirectoryList = new ArrayList<>(dirs.length);

        for (File dir : dirs) {
            if (!dir.isDirectory()) {
                throw new IllegalArgumentException(
                        "All passed in directories must be directories, but \"" + dir.toString() + "\" is not!");
            }

            inputDirectoryList.add(dir);
        }

        inputDirectories = Collections.unmodifiableList(inputDirectoryList);

        directories.addAll(inputDirectories);
    }

    /**
     * Creates a new directory sample stream.
     * @param dir The {@link File directory}.
     * @param fileFilter The {@link FileFilter filter} to apply while enumerating files.
     * @param recursive Enables or disables recursive file listing.
     */
    public DirectorySampleStream(File dir, FileFilter fileFilter, boolean recursive) {
        this(new File[] { dir }, fileFilter, recursive);
    }

    @Override
    public File read() throws IOException {

        while (textFiles.isEmpty() && !directories.isEmpty()) {
            File dir = directories.pop();

            File[] files;

            if (fileFilter != null) {
                files = dir.listFiles(fileFilter);
            } else {
                files = dir.listFiles();
            }

            Arrays.sort(files);

            for (File file : files) {
                if (file.isFile()) {
                    textFiles.push(file);
                } else if (recursive && file.isDirectory()) {
                    directories.push(file);
                }
            }
        }

        if (!textFiles.isEmpty()) {
            return textFiles.pop();
        } else {
            return null;
        }
    }

    @Override
    public void reset() {
        directories.clear();
        textFiles.clear();

        directories.addAll(inputDirectories);
    }

    /**
     * {@inheritDoc}
     * Calling this function has no effect on
     * the stream.
     */
    @Override
    public void close() throws IOException {
    }
}