com.streamsets.pipeline.lib.el.FileEL.java Source code

Introduction

Here is the source code for com.streamsets.pipeline.lib.el.FileEL.java

Source

/*
 * Copyright 2017 StreamSets Inc.
 *
 * Licensed 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 com.streamsets.pipeline.lib.el;

import com.google.common.collect.Iterables;
import com.streamsets.pipeline.api.ElFunction;
import com.streamsets.pipeline.api.ElParam;
import org.apache.commons.io.FilenameUtils;

import java.nio.file.Path;
import java.nio.file.Paths;

public class FileEL {

    private FileEL() {
        // Instantiation is prohibited
    }

    @ElFunction(prefix = "file", name = "fileName", description = "Returns just file name from given path.")
    public static String fileName(@ElParam("filePath") String filePath) {
        if (isEmpty(filePath)) {
            return null;
        }
        return FilenameUtils.getName(filePath);
    }

    @ElFunction(prefix = "file", name = "parentPath", description = "Returns parent path to given file or directory. Returns path without separator (e.g. result will not end with slash).")
    public static String parentPath(@ElParam("filePath") String filePath) {
        if (isEmpty(filePath)) {
            return null;
        }
        return FilenameUtils.getFullPathNoEndSeparator(filePath);
    }

    @ElFunction(prefix = "file", name = "fileExtension", description = "Returns file extension from given path (e.g. 'txt' from /path/file.txt).")
    public static String fileExtension(@ElParam("filePath") String filePath) {
        if (isEmpty(filePath)) {
            return null;
        }

        return FilenameUtils.getExtension(filePath);
    }

    @ElFunction(prefix = "file", name = "removeExtension", description = "Returns path without the extension (e.g. '/path/file' from /path/file.txt).")
    public static String removeExtension(@ElParam("filePath") String filePath) {
        if (isEmpty(filePath)) {
            return null;
        }

        return FilenameUtils.removeExtension(filePath);
    }

    @ElFunction(prefix = "file", name = "pathElement", description = "Returns element (directory or file name) from given index. On path /path/to/file.txt, 'path' have index 0, 'to' have index 1 and file.txt have index 2.")
    public static String pathElement(@ElParam("filePath") String filePath, @ElParam("index") int index) {
        if (isEmpty(filePath)) {
            return null;
        }

        // Array of elements of the path
        Path[] elements = Iterables.toArray(Paths.get(filePath), Path.class);

        // Accept negative index to count from the end of array
        if (index < 0) {
            // Using + as the number is negative, so the resulting operation is actually subtraction
            index = elements.length + index;
        }

        // Index have to be in range, otherwise return null (which will be very likely converted to empty string by EL engine)
        if (index < 0 || index >= elements.length) {
            return null;
        }

        return elements[index].toString();
    }

    private static boolean isEmpty(String str) {
        return str == null || str.isEmpty();
    }

}