/*
 * 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.core.fs.local;

import org.apache.flink.annotation.Internal;
import org.apache.flink.core.fs.RecoverableWriter.CommitRecoverable;
import org.apache.flink.core.fs.RecoverableWriter.ResumeRecoverable;

import java.io.File;

import static org.apache.flink.util.Preconditions.checkArgument;
import static org.apache.flink.util.Preconditions.checkNotNull;

/**
 * An implementation of the resume and commit descriptor objects for local recoverable streams.
 */
@Internal
class LocalRecoverable implements CommitRecoverable, ResumeRecoverable {

	/** The file path for the final result file. */
	private final File targetFile;

	/** The file path of the staging file. */
	private final File tempFile;

	/** The position to resume from. */
	private final long offset;

	/**
	 * Creates a resumable for the given file at the given position.
	 *
	 * @param targetFile The file to resume.
	 * @param offset The position to resume from.
	 */
	LocalRecoverable(File targetFile, File tempFile, long offset) {
		checkArgument(offset >= 0, "offset must be >= 0");
		this.targetFile = checkNotNull(targetFile, "targetFile");
		this.tempFile = checkNotNull(tempFile, "tempFile");
		this.offset = offset;
	}

	public File targetFile() {
		return targetFile;
	}

	public File tempFile() {
		return tempFile;
	}

	public long offset() {
		return offset;
	}

	@Override
	public String toString() {
		return "LocalRecoverable " + tempFile + " @ " + offset + " -> " + targetFile;
	}
}