MimeFileSystem.java

/*!
* Copyright 2010 - 2013 Pentaho Corporation.  All rights reserved.
*
* 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.mime;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.vfs.Capability;
import org.apache.commons.vfs.FileName;
import org.apache.commons.vfs.FileObject;
import org.apache.commons.vfs.FileSystem;
import org.apache.commons.vfs.FileSystemException;
import org.apache.commons.vfs.FileSystemOptions;
import org.apache.commons.vfs.provider.AbstractFileSystem;
import org.apache.commons.vfs.util.SharedRandomContentInputStream;

import javax.mail.MessagingException;
import javax.mail.Part;
import javax.mail.internet.MimeMessage;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collection;

/**
 * An MIME file system.
 *
 * @author <a href="mailto:imario@apache.org">imario@apache.org</a>
 * @version $Revision: 496713 $ $Date: 2007-01-16 09:48:22 -0500 (Tue, 16 Jan 2007) $
 */
public class MimeFileSystem
	extends AbstractFileSystem
	implements FileSystem
{
	private Log log = LogFactory.getLog(MimeFileSystem.class);

	public final static String NULL_BP_NAME = "_body_part_";
	public final static String CONTENT_NAME = "_content";
	public final static String PREAMBLE_CHARSET = "UTF-8";

	private InputStream mimeStream = null;

	protected MimeFileSystem(final FileName rootName, final FileObject parentLayer, final FileSystemOptions fileSystemOptions)
    {
        super(rootName, parentLayer, fileSystemOptions);
	}

	/**
     * Creates a file object.
     */
    protected FileObject createFile(final FileName name) throws FileSystemException
	{
		return new MimeFileObject(name, null, this);
    }

    /**
     * Returns the capabilities of this file system.
     */
    protected void addCapabilities(final Collection caps)
    {
        caps.addAll(MimeFileProvider.capabilities);
    }


	protected void doCloseCommunicationLink()
	{
		try
		{
			if (mimeStream == null)
			{
				return;
			}

			closeMimeStream();
			mimeStream = null;
		}
		catch (IOException e)
		{
			log.warn(e.getLocalizedMessage(), e);
		}
	}

	private void closeMimeStream() throws IOException
	{
		if (mimeStream instanceof SharedRandomContentInputStream)
		{
			((SharedRandomContentInputStream) mimeStream).closeAll();
		}
		else
		{
			mimeStream.close();
		}
	}

	public Part createCommunicationLink() throws IOException, MessagingException
	{
		if (mimeStream != null)
		{
			closeMimeStream();
		}

		FileObject parentLayer = getParentLayer();
		if (!parentLayer.exists())
		{
			return null;
		}

		if (parentLayer.getFileSystem().hasCapability(Capability.RANDOM_ACCESS_READ))
		{
			mimeStream = new SharedRandomContentInputStream(parentLayer);
		}
		else
		{
			mimeStream = getParentLayer().getContent().getInputStream();
		}
		return new MimeMessage(null, mimeStream);
	}
}