info.track_mate.util.DefaultFTPClient.java Source code

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Here is the source code for info.track_mate.util.DefaultFTPClient.java

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/**
 * Copyright 2000-2012 TrackMate
 *
 * 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 info.track_mate.util;

import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Collection;

/**
 * @author Gareth Smith <gareth@track-mate.info>
 */
public class DefaultFTPClient implements FTPClient {

    /** The timeout in milliseconds for the socket connection (value = 2 minutes). */
    private static final int SOCKET_TIMEOUT_MILLIS = 120000;

    /** The FTP connection that this FTPClient wraps. */
    private org.apache.commons.net.ftp.FTPClient ftpClient;

    /** {@inheritDoc} */
    public void connect(String hostname, String username, String password) throws Exception {
        try {
            ftpClient = new org.apache.commons.net.ftp.FTPClient();
            ftpClient.connect(hostname);
            ftpClient.setSoTimeout(SOCKET_TIMEOUT_MILLIS);
            ftpClient.login(username, password);
        } catch (Exception e) {
            throw new Exception("Failed to connect to FTP server", e);
        }
    }

    /** {@inheritDoc} */
    public void disconnect() throws Exception {
        try {
            if (ftpClient != null && ftpClient.isConnected()) {
                ftpClient.disconnect();
            }
        } catch (Exception e) {
            throw new Exception("Failed to disconnect from FTP server", e);
        } finally {
            ftpClient = null;
        }
    }

    /** {@inheritDoc} */
    public FileData download(FTPFile remoteFile) throws Exception {
        return download(remoteFile.getName());
    }

    /** {@inheritDoc} */
    public FileData download(String remoteFileName) throws Exception {
        byte[] dataBytes;
        ByteArrayOutputStream bytesOut = new ByteArrayOutputStream();
        try {
            downloadFile(remoteFileName, bytesOut);
            dataBytes = bytesOut.toByteArray();
        } catch (Exception e) {
            throw new Exception("Failed to download file", e);
        } finally {
            bytesOut.flush();
            bytesOut.close();
        }

        DefaultFileData fileData = new DefaultFileData();
        fileData.setName(remoteFileName);
        fileData.setData(dataBytes);

        return fileData;
    }

    /** {@inheritDoc} */
    public File downloadToDisk(FTPFile remoteFile, String localFilePath) throws Exception {
        return downloadToDisk(remoteFile.getName(), localFilePath);
    }

    /** {@inheritDoc} */
    public File downloadToDisk(String remoteFileName, String localFilePath) throws Exception {

        OutputStream fileOut = null;
        try {
            fileOut = new BufferedOutputStream(new FileOutputStream(localFilePath));
            downloadFile(remoteFileName, fileOut);

        } catch (Exception e) {
            throw new Exception("Failed to download file to disk", e);
        } finally {
            if (fileOut != null) {
                fileOut.flush();
                fileOut.close();
            }
        }

        return new File(localFilePath);
    }

    /** {@inheritDoc} */
    public Collection<FTPFile> listFiles() throws Exception {
        org.apache.commons.net.ftp.FTPFile[] ftpFiles = ftpClient.listFiles();
        Collection<FTPFile> toReturn = new ArrayList<FTPFile>();
        for (org.apache.commons.net.ftp.FTPFile ftpFile : ftpFiles) {
            toReturn.add(new DefaultFTPFile(ftpFile.getName(), ftpFile.getSize()));
        }
        return toReturn;
    }

    /** {@inheritDoc} */
    public void changeDirectory(String directoryName) throws Exception {
        try {
            ftpClient.changeWorkingDirectory(directoryName);
        } catch (Exception e) {
            throw new Exception("Failed to change working directory", e);
        }
    }

    // ------ Private Helpers ------

    /**
     * Download the specified remote file to the provided output stream.
     * @param remoteFileName The name of the remote file to download.
     * @param outputStream The stream to write the remote file's contents to.
     * @throws Exception If the operation fails.
     */
    private void downloadFile(String remoteFileName, OutputStream outputStream) throws Exception {
        ftpClient.retrieveFile(remoteFileName, outputStream);
    }
}