mail/internet/MimePartDataSource.java

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package javax.mail.internet;

import javax.mail.*;
import javax.activation.*;
import java.io.*;
import java.net.UnknownServiceException;
import com.sun.mail.util.PropUtil;
import com.sun.mail.util.FolderClosedIOException;

/**
 * A utility class that implements a DataSource out of
 * a MimePart. This class is primarily meant for service providers.
 *
 * @see     javax.mail.internet.MimePart
 * @see     javax.activation.DataSource
 * @author  John Mani
 */

public class MimePartDataSource implements DataSource, MessageAware {
    /**
     * The MimePart that provides the data for this DataSource.
     *
     * @since   JavaMail 1.4
     */
    protected MimePart part;

    private MessageContext context;

    /**
     * Constructor, that constructs a DataSource from a MimePart.
     *
     * @param   part    the MimePart
     */
    public MimePartDataSource(MimePart part) {
    this.part = part;
    }

    /**
     * Returns an input stream from this  MimePart. <p>
     *
     * This method applies the appropriate transfer-decoding, based
     * on the Content-Transfer-Encoding attribute of this MimePart.
     * Thus the returned input stream is a decoded stream of bytes.<p>
     *
     * This implementation obtains the raw content from the Part
     * using the <code>getContentStream()</code> method and decodes
     * it using the <code>MimeUtility.decode()</code> method.
     *
     * @see javax.mail.internet.MimeMessage#getContentStream
     * @see javax.mail.internet.MimeBodyPart#getContentStream
     * @see javax.mail.internet.MimeUtility#decode
     * @return  decoded input stream
     */
    public InputStream getInputStream() throws IOException {
    InputStream is;

    try {
        if (part instanceof MimeBodyPart)
        is = ((MimeBodyPart)part).getContentStream();
        else if (part instanceof MimeMessage)
        is = ((MimeMessage)part).getContentStream();
        else
        throw new MessagingException("Unknown part");

        String encoding =
        MimeBodyPart.restrictEncoding(part, part.getEncoding());
        if (encoding != null)
        return MimeUtility.decode(is, encoding);
        else
        return is;
    } catch (FolderClosedException fex) {
        throw new FolderClosedIOException(fex.getFolder(),
                        fex.getMessage());
    } catch (MessagingException mex) {
        IOException ioex = new IOException(mex.getMessage());
        ioex.initCause(mex);
        throw ioex;
    }
    }

    /**
     * DataSource method to return an output stream. <p>
     *
     * This implementation throws the UnknownServiceException.
     */
    public OutputStream getOutputStream() throws IOException {
    throw new UnknownServiceException("Writing not supported");
    }

    /**
     * Returns the content-type of this DataSource. <p>
     *
     * This implementation just invokes the <code>getContentType</code>
     * method on the MimePart.
     */
    public String getContentType() {
    try {
        return part.getContentType();
    } catch (MessagingException mex) {
        // would like to be able to reflect the exception to the
        // application, but since we can't do that we return a
        // generic "unknown" value here and hope for another
        // exception later.
        return "application/octet-stream";
    }
    }

    /**
     * DataSource method to return a name.  <p>
     *
     * This implementation just returns an empty string.
     */
    public String getName() {
    try {
        if (part instanceof MimeBodyPart)
        return ((MimeBodyPart)part).getFileName();
    } catch (MessagingException mex) {
        // ignore it
    }
    return "";
    }

    /**
     * Return the <code>MessageContext</code> for the current part.
     * @since JavaMail 1.1
     */
    public synchronized MessageContext getMessageContext() {
    if (context == null)
        context = new MessageContext(part);
    return context;
    }
}