xfafile.java

处理PDF

/*
 * $Id: XfaFile.java 3117 2008-01-31 05:53:22Z xlv $
 *
 * Copyright 2007 Bruno Lowagie.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

package com.lowagie.rups.model;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

import com.lowagie.rups.io.OutputStreamResource;

/** Class that deals with the XFA file that can be inside a PDF file. */
public class XfaFile implements OutputStreamResource {

	/** The X4J Document object (XML). */
	protected Document xfaDocument;
	
	/**
	 * Constructs an XFA file from an OutputStreamResource.
	 * This resource can be an XML file or a node in a RUPS application.
	 * @param	resource	the XFA resource
	 * @throws IOException 
	 * @throws DocumentException 
	 */
	public XfaFile(OutputStreamResource resource) throws IOException, DocumentException {
		// Is there a way to avoid loading everything in memory?
		// Can we somehow get the XML from the PDF as an InputSource, Reader or InputStream?
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		resource.writeTo(baos);
		ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
		SAXReader reader = new SAXReader();
		xfaDocument = reader.read(bais);
	}

	/**
	 * Getter for the XFA Document object.
	 * @return	a Document object (X4J)
	 */
	public Document getXfaDocument() {
		return xfaDocument;
	}

	/**
	 * Writes a formatted XML file to the OutputStream.
	 * @see com.lowagie.rups.io.OutputStreamResource#writeTo(java.io.OutputStream)
	 */
	public void writeTo(OutputStream os) throws IOException {
		if (xfaDocument == null)
			return;
		OutputFormat format = new OutputFormat("   ", true);
        XMLWriter writer = new XMLWriter(os, format);
        writer.write(xfaDocument);
	}
}