flink-connectors/flink-file-sink-common/src/main/java/org/apache/flink/streaming/api/functions/sink/filesystem/InProgressFileWriter.java

/*
 * 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 org.apache.flink.streaming.api.functions.sink.filesystem;

import org.apache.flink.annotation.Internal;
import org.apache.flink.core.fs.Path;

import javax.annotation.Nullable;

import java.io.IOException;

/** The {@link Bucket} uses the {@link InProgressFileWriter} to write element to a part file. */
@Internal
public interface InProgressFileWriter<IN, BucketID>
        extends PartFileInfo<BucketID>, RecordWiseCompactingFileWriter<IN> {

    /**
     * Write an element to the part file.
     *
     * @param element the element to be written.
     * @param currentTime the writing time.
     * @throws IOException Thrown if writing the element fails.
     */
    void write(final IN element, final long currentTime) throws IOException;

    /**
     * @return The state of the current part file.
     * @throws IOException Thrown if persisting the part file fails.
     */
    InProgressFileRecoverable persist() throws IOException;

    /**
     * @return The state of the pending part file. {@link Bucket} uses this to commit the pending
     *     file.
     * @throws IOException Thrown if an I/O error occurs.
     */
    PendingFileRecoverable closeForCommit() throws IOException;

    /** Dispose the part file. */
    void dispose();

    @Override
    default void write(IN element) throws IOException {
        write(element, System.currentTimeMillis());
    }

    // ------------------------------------------------------------------------

    /** A handle can be used to recover in-progress file.. */
    interface InProgressFileRecoverable extends PendingFileRecoverable {}

    /** The handle can be used to recover pending file. */
    interface PendingFileRecoverable {

        /** @return The target path of the pending file, null if unavailable. */
        @Nullable
        Path getPath();

        /** @return The size of the pending file, -1 if unavailable. */
        long getSize();
    }
}