source: 3thparty/jupload/src/main/java/wjhk/jupload2/filedata/FileData.java @ 3951

//
// $Id: FileData.java 95 2007-05-02 03:27:05Z
// /C=DE/ST=Baden-Wuerttemberg/O=ISDN4Linux/OU=Fritz
// Elfert/CN=svn-felfert@isdn4linux.de/emailAddress=fritz@fritz-elfert.de $
//
// jupload - A file upload applet.
// Copyright 2007 The JUpload Team
//
// Created: 2006-11-20
// Creator: etienne_sf
// Last modified: $Date: 2010-06-28 08:35:55 -0300 (Seg, 28 Jun 2010) $
//
// This program is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free Software
// Foundation; either version 2 of the License, or (at your option) any later
// version. This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
// details. You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation, Inc.,
// 675 Mass Ave, Cambridge, MA 02139, USA.

package wjhk.jupload2.filedata;

import java.io.File;
import java.io.InputStream;
import java.util.Date;

import wjhk.jupload2.exception.JUploadException;
import wjhk.jupload2.exception.JUploadIOException;
import wjhk.jupload2.policies.UploadPolicy;
import wjhk.jupload2.upload.FileUploadThread;
import wjhk.jupload2.upload.helper.ByteArrayEncoder;

/**
 * This class contains all data and methods for a file to upload. The current
 * {@link wjhk.jupload2.policies.UploadPolicy} contains the necessary parameters
 * to personalize the way files must be handled. <BR>
 * The JUpload package provides a default implementation of this class in
 * {@link DefaultFileData}. This default implementation contains all necessary
 * methods to allow upload. You can override it to add new file behaviour. For
 * instance, you could add a XMLFileData, that would check that XML is valid
 * before upload. See the <a href="package-summary.html">package summary</a> for
 * more details about that. <BR>
 * This class is the interface that all FileData must implement. The
 * {@link DefaultFileData} class contains the default implementation for this
 * interface. The {@link PictureFileData} contains another implementation of
 * this interface, adapted to manage pictures (rotation, resizing...). <BR>
 * The instance of FileData is created by the
 * {@link UploadPolicy#createFileData(File, File)} method. This method can be
 * overrided in a new upoad policy, to create an instance of another FileData.
 * See {@link PictureFileData} for an example about FileData customization.
 * 
 * @author etienne_sf
 */

public interface FileData {

        /**
         * Called during the upload, by the {@link FileUploadThread}. The FileData
         * instance should then call the
         * {@link ByteArrayEncoder#appendTextProperty(String, String, int)} method
         * to add each file property to the current upload.
         * 
         * @param bae
         *            The byte encoder, where the properties must be added
         * @param index
         *            Index of the file concerned by this value. -1 if this is a
         *            global parameter.
         * @throws JUploadIOException
         *             Encapsulation of the IOException, if any would occurs.
         * @see ByteArrayEncoder#appendTextProperty(String, String, int)
         */
        public void appendFileProperties(ByteArrayEncoder bae, int index)
                        throws JUploadIOException;

        /**
         * Prepare the fileData to upload. For instance, picture data can be resized
         * before upload (see {@link PictureFileData}. This method is called before
         * the upload of this file. If no exception is thrown, then the file is
         * correctly prepared.
         * 
         * @see FileUploadThread
         * @throws JUploadException
         *             Encapsulation of the Exception, if any error would occurs.
         */
        public void beforeUpload() throws JUploadException;

        /**
         * Get size of upload, which may be different from the actual file length.
         * This call is valid only after a call to {@link #beforeUpload()} and
         * before the call to {@link #afterUpload()}.
         * 
         * @return The length of upload. In this class, this is the size of the
         *         file, as it isn't transformed for upload. This size may change if
         *         encoding is necessary (needs a new FileData class), or if picture
         *         is to be resized or rotated.
         * @see PictureFileData
         */
        public long getUploadLength();

        /**
         * This function is called after upload, whether it is successful or not. It
         * allows fileData to free any resource created for the upload. For
         * instance, {@link PictureFileData#afterUpload()} removes the temporary
         * file, if any was created.
         */
        public void afterUpload();

        /**
         * This function creates an InputStream from this file. The
         * {@link FileUploadThread} class then reads bytes from it and transfers
         * them to the webserver. The caller is responsible for closing this stream.<BR>
         * This method may only be called when {@link #isPreparedForUpload()}
         * returns true.
         * 
         * @throws JUploadException
         *             Encapsulation of the Exception, if any would occurs.
         * @throws IllegalStateException
         *             When the upload is not prepared (before a call to
         *             {@link #beforeUpload()} or after a call to
         *             {@link #afterUpload()}
         * @return An InputStream, representing this instance.
         */
        public InputStream getInputStream() throws JUploadException;

        /**
         * Get the original filename. This is the name of the file, into the local
         * hardrive
         * 
         * @return The original filename
         */
        public String getFileName();

        /**
         * @return The extension for the original file.
         */
        public String getFileExtension();

        /**
         * @return The length of the original file.
         */
        public long getFileLength();

        /**
         * @return The original file date.
         */
        public Date getLastModified();

        /**
         * Get the directory of the file.
         * 
         * @return The directory where this file is stored.
         */
        public String getDirectory();

        /**
         * Retrieves the MD5 sum of the file.<BR>
         * Since 5.0.0, this method is is in DefaultFileData, and is calculated
         * depending on the sendMD5Sum applet parameter, during the file preparation
         * file.
         * 
         * @return The corresponding MD5 sum.
         * @throws JUploadException 
         * @see #beforeUpload()
         */
        public String getMD5() throws JUploadException;

        /**
         * This function return the FileData content type.
         * 
         * @return The mimeType for the file.
         */
        public String getMimeType();

        /**
         * Indicate if this file can be read. Take care of the File.canRead()
         * methods, that seems to be wrong from time to time.
         * 
         * @return indicates whether the file can be read or not.
         */
        public boolean canRead();

        /**
         * Standard getter, for the file described by the FileData instance.
         * 
         * @return the File instance associated with this row.
         */
        public File getFile();

        /**
         * Retrieves the path of this file relative to it's root dir
         * 
         * @return This instance's relative path or an empty string if it was not
         *         created using a root parameter.
         */
        public String getRelativeDir();

        /**
         * Indicates whether the file can be uploaded or not. This boolean should be
         * set to true in the call to {@link #beforeUpload()}, and the to false in
         * the call to {@link #afterUpload()}.
         * 
         * @return True if the file is ready for upload.
         * @throws IllegalStateException
         *             When the upload is not prepared (before a call to
         *             {@link #beforeUpload()} or after a call to
         *             {@link #afterUpload()}
         */
        public boolean isPreparedForUpload();
}