RemoteFileSystemFactory.java

package com.cloudhopper.commons.rfs;

/*
 * #%L
 * ch-commons-rfs
 * %%
 * Copyright (C) 2012 - 2013 Cloudhopper by Twitter
 * %%
 * 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.
 * #L%
 */

import com.cloudhopper.commons.rfs.provider.BaseRemoteFileSystem;
import com.cloudhopper.commons.util.URL;
import com.cloudhopper.commons.util.URLParser;
import java.net.MalformedURLException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Factory for creating remote filesystems from a URL.
 * 
 * @author joelauer
 */
public class RemoteFileSystemFactory {
    private static final Logger logger = LoggerFactory.getLogger(RemoteFileSystemFactory.class);

    private RemoteFileSystemFactory() {
        // only static methods
    }

    /**
     * Creates a new RemoteFileSystem by parsing the URL and creating the
     * correct underlying provider to support the protocol.
     */
    public static RemoteFileSystem create(String url) throws MalformedURLException, FileSystemException {
        // parse url into a URL object
        URL r = URLParser.parse(url);
        // delegate responsibility to other method
        return create(r);
    }

    public static RemoteFileSystem create(URL url) throws MalformedURLException, FileSystemException {
        // try to match the url to a provider
        Protocol protocol = Protocol.findByName(url.getProtocol());
        if (protocol == null) {
            throw new MalformedURLException("Unsupported virtual filesystem protocol '" + url.getProtocol() + "'");
        }

        // create a new instance of the provider and return it
        BaseRemoteFileSystem vfs = null;
        try {
            Class vfsClass = protocol.getProvider();
            // create a new instance, cast it
            vfs = (BaseRemoteFileSystem)vfsClass.newInstance();
        } catch (Exception e) {
            throw new FileSystemException("Could not create instance of " + protocol.getProvider(), e);
        }

        // setup any common properties
        vfs.setURL(url);
        vfs.setProtocol(protocol);

        // validate the properties
        vfs.validateURL();

        return vfs;
    }

}