hssfeventfactory.java

Office格式转换代码

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache POI" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache POI", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.poi.hssf.eventusermodel;

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

import org.apache.poi.util.LittleEndian;
import org.apache.poi.hssf.eventusermodel.HSSFUserException;
import org.apache.poi.hssf.record.RecordFormatException;
import org.apache.poi.hssf.record.Record;
import org.apache.poi.hssf.record.RecordFactory;
import org.apache.poi.hssf.record.ContinueRecord;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;

/**
 * Low level event based HSSF reader.  Pass either a DocumentInputStream to
 * process events along with a request object or pass a POIFS POIFSFileSystem to
 * processWorkbookEvents along with a request.
 *
 * This will cause your file to be processed a record at a time.  Each record with
 * a static id matching one that you have registed in your HSSFRequest will be passed
 * to your associated HSSFListener.
 *
 * @see org.apache.poi.hssf.dev.EFHSSF
 *
 * @author Andrew C. Oliver (acoliver at apache dot org)
 * @author Carey Sublette  ([e-mail])
 */

public class HSSFEventFactory
{
    /** Creates a new instance of HSSFEventFactory */

    public HSSFEventFactory()
    {
    }

    /**
     * Processes a file into essentially record events.
     *
     * @param req       an Instance of HSSFRequest which has your registered listeners
     * @param fs        a POIFS filesystem containing your workbook
     */

    public void processWorkbookEvents(HSSFRequest req, POIFSFileSystem fs)
        throws IOException
    {
        InputStream in = fs.createDocumentInputStream("Workbook");

        processEvents(req, in);
    }

    /**
	 * Processes a file into essentially record events.
	 *
	 * @param req       an Instance of HSSFRequest which has your registered listeners
	 * @param fs        a POIFS filesystem containing your workbook
	 * @return 			numeric user-specified result code.
	 */

	public short abortableProcessWorkbookEvents(HSSFRequest req, POIFSFileSystem fs)
		throws IOException, HSSFUserException
	{
		InputStream in = fs.createDocumentInputStream("Workbook");
		return abortableProcessEvents(req, in);
    }

    /**
     * Processes a DocumentInputStream into essentially Record events.
     *
     * If an <code>AbortableHSSFListener</code> causes a halt to processing during this call
     * the method will return just as with <code>abortableProcessEvents</code>, but no
     * user code or <code>HSSFUserException</code> will be passed back.
     *
     * @see org.apache.poi.poifs.filesystem.POIFSFileSystem#createDocumentInputStream(String)
     * @param req       an Instance of HSSFRequest which has your registered listeners
     * @param in        a DocumentInputStream obtained from POIFS's POIFSFileSystem object
     */

    public void processEvents(HSSFRequest req, InputStream in)
        throws IOException
	{
		try
		{
			genericProcessEvents(req, in);
		}
		catch (HSSFUserException hue)
		{/*If an HSSFUserException user exception is thrown, ignore it.*/ }
	}


    /**
     * Processes a DocumentInputStream into essentially Record events.
     *
     * @see org.apache.poi.poifs.filesystem.POIFSFileSystem#createDocumentInputStream(String)
     * @param req       an Instance of HSSFRequest which has your registered listeners
     * @param in        a DocumentInputStream obtained from POIFS's POIFSFileSystem object
	 * @return 			numeric user-specified result code.
     */

    public short abortableProcessEvents(HSSFRequest req, InputStream in)
        throws IOException, HSSFUserException
    {
		return genericProcessEvents(req, in);
    }

     /**
	 * Processes a DocumentInputStream into essentially Record events.
	 *
	 * @see org.apache.poi.poifs.filesystem.POIFSFileSystem#createDocumentInputStream(String)
	 * @param req       an Instance of HSSFRequest which has your registered listeners
	 * @param in        a DocumentInputStream obtained from POIFS's POIFSFileSystem object
	 * @param in        a DocumentInputStream obtained from POIFS's POIFSFileSystem object
	 * @return 			numeric user-specified result code.
	 */

	protected short genericProcessEvents(HSSFRequest req, InputStream in)
		throws IOException, HSSFUserException
	{
		short userCode = 0;

		short sid = 0;
		process:
		try
		{
			byte[] sidbytes  = new byte[ 2 ];
			int    bytesread = in.read(sidbytes);
			Record rec       = null;

			while (bytesread > 0)
			{

				sid = LittleEndian.getShort(sidbytes);
                
                //
                // for some reasons we have to make the workbook to be at least 4096 bytes
                // but if we have such workbook we fill the end of it with zeros (many zeros)
                //
                // it is not good:
                // if the length( all zero records ) % 4 = 1
                // e.g.: any zero record would be readed as  4 bytes at once ( 2 - id and 2 - size ).
                // And the last 1 byte will be readed WRONG ( the id must be 2 bytes )
                //
                // So we should better to check if the sid is zero and not to read more data
                // The zero sid shows us that rest of the stream data is a fake to make workbook 
                // certain size
                //
                if ( sid == 0 )
                    break;


				if ((rec != null) && (sid != ContinueRecord.sid))
				{
					userCode = req.processRecord(rec);
					if (userCode != 0) break process;
				}
				if (sid != ContinueRecord.sid)
				{
					short  size = LittleEndian.readShort(in);
					byte[] data = new byte[ size ];

					if (data.length > 0)
					{
						in.read(data);
					}
                                        //System.out.println("creating "+sid);
					Record[] recs = RecordFactory.createRecord(sid, size,
															   data);

					if (recs.length > 1)
					{                                // we know that the multiple
						for (int k = 0; k < (recs.length - 1); k++)
						{                            // record situations do not
							userCode = req.processRecord(
								recs[ k ]);          // contain continue records
							if (userCode != 0) break process;
						}
					}
					rec = recs[ recs.length - 1 ];   // regardless we'll process

					// the last record as though
					// it might be continued
					// if there is only one
					// records, it will go here too.
				}
				else
				{                                    // we do have a continue record
					short  size = LittleEndian.readShort(in);
					byte[] data = new byte[ size ];

					if (data.length > 0)
					{
						in.read(data);
					}
					rec.processContinueRecord(data);
				}
				bytesread = in.read(sidbytes);       // read next record sid
			}
			if (rec != null)
			{
				userCode = req.processRecord(rec);
				if (userCode != 0) break process;
			}
		}
		catch (IOException e)
		{
			throw new RecordFormatException("Error reading bytes" +
                        "while processing record sid="+sid);
		}
		return userCode;

		// Record[] retval = new Record[ records.size() ];
		// retval = ( Record [] ) records.toArray(retval);
		// return null;
    }
}