LocalFileMover.java

package org.araqne.logdb;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;

import org.araqne.logdb.query.command.IoHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class LocalFileMover implements FileMover {
	private final Logger logger = LoggerFactory.getLogger(LocalFileMover.class);
	private boolean overwrite;
	
	public LocalFileMover() {
		this(false);
	}

	public LocalFileMover(boolean overwrite) {
		this.overwrite = overwrite;
	}

	@Override
	public void move(String from, String to) throws IOException {
		File fromFile = new File(from);
		File toFile = new File(to);

		if (!fromFile.exists())
			throw new IOException("file not found: " + from);

		if (toFile.exists()) {
			if (overwrite) {
				if (!toFile.delete())
					throw new IOException("cannot overwrite file: " + toFile.getAbsolutePath());
			} else {
				throw new IOException("file already exist: " + to);
			}
		}

		boolean moved = fromFile.renameTo(toFile);
		boolean copied = false;
		if (moved) {
			logger.debug("araqne logdb: moved file from [{}] to [{}]", fromFile.getAbsolutePath(), toFile.getAbsolutePath());
		} else {
			FileInputStream fis = null;
			FileOutputStream fos = null;
			FileChannel fromChannel = null;
			FileChannel toChannel = null;
			try {
				toFile.getParentFile().mkdirs();

				fis = new FileInputStream(fromFile);
				fos = new FileOutputStream(toFile);

				fromChannel = fis.getChannel();
				toChannel = fos.getChannel();

				ensureTransferTo(fromChannel, toChannel, fromChannel.size());
				copied = true;
			} finally {
				IoHelper.close(fromChannel);
				IoHelper.close(toChannel);
				IoHelper.close(fis);
				IoHelper.close(fos);

				if (copied) {
					boolean deleted = fromFile.delete();
					if (!deleted) {
						logger.debug("araqne logdb: delete [{}] failed after copy", fromFile.getAbsolutePath());
					}
				}
			}
		}
	}

	private void ensureTransferTo(FileChannel srcChannel, FileChannel dstChannel, long length) throws IOException {
		long copied = 0;
		while (copied < length) {
			copied += srcChannel.transferTo(copied, length - copied, dstChannel);
		}
	}

}