nl.vpro.nep.service.NEPDownloadService Maven / Gradle / Ivy

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Support for the several APIs of NEP that POMS is integrating with

There is a newer version: 8.3.1

package nl.vpro.nep.service;

import java.io.IOException;
import java.io.OutputStream;
import java.time.Duration;
import java.util.function.Function;
import java.util.function.Supplier;

import org.apache.commons.lang3.StringUtils;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;

import nl.vpro.util.FileMetadata;

public interface NEPDownloadService {
    /**
     * Wait until the given file is available on the NEP download ftp server, then copy it to the given outputStream.
     * 
     * Before that, the descriptorConsumer will be called. If it returns false, the copying will not happen
     *
     * @throws IllegalStateException If the file didn't appear in time
     * @param descriptorConsumer If the file is found, and this is not null it's descriptor will be fed to this function
     *                           You can use it for logging only and return {@link Proceed#TRUE} always. You can also return something else.
     */
    void download(
        @NonNull String directory,
        @NonNull String nepFile,
        @NonNull Supplier outputStream,
        @NonNull Duration timeout,
        @Nullable Function descriptorConsumer) throws IOException;

    /**
     * Download the given file from the NEP ftp server to the given outputStream.
     */
    default void download(
        @NonNull String directory,
        @NonNull String nepFile,
        @NonNull  Supplier outputStream,
        @NonNull Function descriptorConsumer) throws IOException {
        download(directory, nepFile, outputStream, Duration.ZERO, descriptorConsumer);
    }

    String getDownloadString();

    enum Proceed {
        /**
         * The file is ok, simply proceed downloading it.
         */
        TRUE,
        /**
         * The file is not ok, it may be too old or different than expected. Wait a bit and retry this.
         */
        RETRY,
        /**
         * The file is not ok, it may be too old or different than expected. There is no point in waiting.
         */
        FALSE
    }


    static String join(String directory, String file) {
        if (StringUtils.isBlank(directory)) {
            return file;
        } else {
            return directory + "/" + file;
        }
    }

}