src/java/org/apache/commons/vfs/provider/ftp/FTPClientWrapper.java

/*
 * Copyright 2002-2005 The Apache Software Foundation.
 *
 * 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 org.apache.commons.vfs.provider.ftp;

import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPConnectionClosedException;
import org.apache.commons.net.ftp.FTPFile;
import org.apache.commons.vfs.FileSystemException;
import org.apache.commons.vfs.FileSystemOptions;
import org.apache.commons.vfs.provider.GenericFileName;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * A wrapper to the FTPClient to allow automatic reconnect on connection loss.<br />
 * I decided to not to use eg. noop() to determine the state of the connection to avoid unnecesary server round-trips.
 */
class FTPClientWrapper implements FtpClient
{
    private final GenericFileName root;
    private final FileSystemOptions fileSystemOptions;

    private FTPClient ftpClient = null;

    FTPClientWrapper(final GenericFileName root, final FileSystemOptions fileSystemOptions) throws FileSystemException
    {
        this.root = root;
        this.fileSystemOptions = fileSystemOptions;
        getFtpClient(); // fail-fast
    }

    public GenericFileName getRoot()
    {
        return root;
    }

    public FileSystemOptions getFileSystemOptions()
    {
        return fileSystemOptions;
    }

    private FTPClient createClient() throws FileSystemException
    {
        final GenericFileName rootName = getRoot();

        return FtpClientFactory.createConnection(rootName.getHostName(),
            rootName.getPort(),
            rootName.getUserName(),
            rootName.getPassword(),
            rootName.getPath(),
            getFileSystemOptions());
    }

    private FTPClient getFtpClient() throws FileSystemException
    {
        if (ftpClient == null)
        {
            ftpClient = createClient();
        }

        return ftpClient;
    }

    public boolean isConnected() throws FileSystemException
    {
        return getFtpClient().isConnected();
    }

    public void disconnect() throws IOException
    {
        try
        {
            getFtpClient().disconnect();
        }
        finally
        {
            ftpClient = null;
        }
    }

    public FTPFile[] listFiles(String key, String relPath) throws IOException
    {
        try
        {
            return getFtpClient().listFiles(key, relPath);
        }
        catch (FTPConnectionClosedException e)
        {
            disconnect();
            return getFtpClient().listFiles(key, relPath);
        }
    }

    public boolean removeDirectory(String relPath) throws IOException
    {
        try
        {
            return getFtpClient().removeDirectory(relPath);
        }
        catch (FTPConnectionClosedException e)
        {
            disconnect();
            return getFtpClient().removeDirectory(relPath);
        }
    }

    public boolean deleteFile(String relPath) throws IOException
    {
        try
        {
            return getFtpClient().deleteFile(relPath);
        }
        catch (FTPConnectionClosedException e)
        {
            disconnect();
            return getFtpClient().deleteFile(relPath);
        }
    }

    public boolean rename(String oldName, String newName) throws IOException
    {
        try
        {
            return getFtpClient().rename(oldName, newName);
        }
        catch (FTPConnectionClosedException e)
        {
            disconnect();
            return getFtpClient().rename(oldName, newName);
        }
    }

    public boolean makeDirectory(String relPath) throws IOException
    {
        try
        {
            return getFtpClient().makeDirectory(relPath);
        }
        catch (FTPConnectionClosedException e)
        {
            disconnect();
            return getFtpClient().makeDirectory(relPath);
        }
    }

    public boolean completePendingCommand() throws IOException
    {
        if (ftpClient != null)
        {
            return getFtpClient().completePendingCommand();
        }

        return true;
    }

    public InputStream retrieveFileStream(String relPath) throws IOException
    {
        try
        {
            return getFtpClient().retrieveFileStream(relPath);
        }
        catch (FTPConnectionClosedException e)
        {
            disconnect();
            return getFtpClient().retrieveFileStream(relPath);
        }
    }

    public InputStream retrieveFileStream(String relPath, long restartOffset) throws IOException
    {
        try
        {
            FTPClient client = getFtpClient();
            client.setRestartOffset(restartOffset);
            return client.retrieveFileStream(relPath);
        }
        catch (FTPConnectionClosedException e)
        {
            disconnect();

            FTPClient client = getFtpClient();
            client.setRestartOffset(restartOffset);
            return client.retrieveFileStream(relPath);
        }
    }

    public OutputStream appendFileStream(String relPath) throws IOException
    {
        try
        {
            return getFtpClient().appendFileStream(relPath);
        }
        catch (FTPConnectionClosedException e)
        {
            disconnect();
            return getFtpClient().appendFileStream(relPath);
        }
    }

    public OutputStream storeFileStream(String relPath) throws IOException
    {
        try
        {
            return getFtpClient().storeFileStream(relPath);
        }
        catch (FTPConnectionClosedException e)
        {
            disconnect();
            return getFtpClient().storeFileStream(relPath);
        }
    }

    public boolean abort() throws IOException
    {
        try
        {
            // imario@apache.org: 2005-02-14
            // it should be better to really "abort" the transfer, but
            // currently I didnt manage to make it work - so lets "abort" the hard way.
            // return getFtpClient().abort();
            
            disconnect();
            return true;
        }
        catch (FTPConnectionClosedException e)
        {
            disconnect();
        }
        return true;
    }
}