cosdocument.java

非常有用的操作pdf文件的java源码

/**
 * Copyright (c) 2003-2006, www.pdfbox.org
 * 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. Neither the name of pdfbox; nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS 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 REGENTS OR 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.
 *
 * http://www.pdfbox.org
 *
 */
package org.pdfbox.cos;

import java.io.File;
import java.io.IOException;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;


import org.pdfbox.exceptions.COSVisitorException;
import org.pdfbox.io.RandomAccess;
import org.pdfbox.io.RandomAccessFile;

import org.pdfbox.pdfparser.PDFObjectStreamParser;
import org.pdfbox.persistence.util.COSObjectKey;

/**
 * This is the in-memory representation of the PDF document.  You need to call
 * close() on this object when you are done using it!!
 *
 * @author <a href="[e-mail]">Ben Litchfield</a>
 * @version $Revision: 1.28 $
 */
public class COSDocument extends COSBase
{
    private float version;
    
    /**
     * added objects (actually preserving original sequence).
     */
    private List objects = new ArrayList();
    
    /**
     * a pool of objects read/referenced so far
     * used to resolve indirect object references.
     */
    private Map objectPool = new HashMap();

    /**
     * Document trailer dictionary.
     */
    private COSDictionary trailer;

    /**
     * This file will store the streams in order to conserve memory.
     */
    private RandomAccess scratchFile = null;
    
    private File tmpFile = null;
    
    private String headerString = "%PDF-1.4";

    /**
     * Constructor.  Uses the java.io.tmpdir value to create a file
     * to store the streams.
     *
     *  @throws IOException If there is an error creating the tmp file.
     */
    public COSDocument() throws IOException
    {
        this( new File( System.getProperty( "java.io.tmpdir" ) ) );
    }

    /**
     * Constructor that will create a create a scratch file in the
     * following directory.
     *
     * @param scratchDir The directory to store a scratch file.
     *
     *  @throws IOException If there is an error creating the tmp file.
     */
    public COSDocument( File scratchDir ) throws IOException
    {
        tmpFile = File.createTempFile( "pdfbox", "tmp", scratchDir );
        scratchFile = new RandomAccessFile( tmpFile, "rw" );
    }

    /**
     * Constructor that will use the following random access file for storage
     * of the PDF streams.  The client of this method is responsible for deleting
     * the storage if necessary that this file will write to.  The close method
     * will close the file though.
     *
     * @param file The random access file to use for storage.
     */
    public COSDocument( RandomAccess file )
    {
        scratchFile = file;
    }

    /**
     * This will get the scratch file for this document.
     *
     * @return The scratch file.
     */
    public RandomAccess getScratchFile()
    {
        return scratchFile;
    }

    /**
     * This will get the first dictionary object by type.
     *
     * @param type The type of the object.
     *
     * @return This will return an object with the specified type.
     */
    public COSObject getObjectByType( String type )
    {
        return getObjectByType( COSName.getPDFName( type ) );
    }
    
    /**
     * This will get the first dictionary object by type.
     *
     * @param type The type of the object.
     *
     * @return This will return an object with the specified type.
     */
    public COSObject getObjectByType( COSName type )
    {
        COSObject retval = null;
        Iterator iter = objects.iterator();
        while( iter.hasNext() && retval == null)
        {
            COSObject object = (COSObject)iter.next();

            COSBase realObject = object.getObject();
            if( realObject instanceof COSDictionary )
            {
                COSDictionary dic = (COSDictionary)realObject;
                COSName objectType = (COSName)dic.getItem( COSName.TYPE );
                if( objectType != null && objectType.equals( type ) )
                {
                    retval = object;
                }
            }
        }
        return retval;
    }
    
    /**
     * This will get all dictionary objects by type.
     *
     * @param type The type of the object.
     *
     * @return This will return an object with the specified type.
     */
    public List getObjectsByType( String type )
    {
        return getObjectsByType( COSName.getPDFName( type ) );
    }
    
    /**
     * This will get a dictionary object by type.
     *
     * @param type The type of the object.
     *
     * @return This will return an object with the specified type.
     */
    public List getObjectsByType( COSName type )
    {
        List retval = new ArrayList();
        Iterator iter = objects.iterator();
        while( iter.hasNext() )
        {
            COSObject object = (COSObject)iter.next();

            COSBase realObject = object.getObject();
            if( realObject instanceof COSDictionary )
            {
                COSDictionary dic = (COSDictionary)realObject;
                COSName objectType = (COSName)dic.getItem( COSName.TYPE );
                if( objectType != null && objectType.equals( type ) )
                {
                    retval.add( object );
                }
            }
        }
        return retval;
    }

    /**
     * This will print contents to stdout.
     */
    public void print()
    {
        Iterator iter = objects.iterator();
        while( iter.hasNext() )
        {
            COSObject object = (COSObject)iter.next();
            System.out.println( object);
        }
    }

    /**
     * This will set the version of this PDF document.
     *
     * @param versionValue The version of the PDF document.
     */
    public void setVersion( float versionValue )
    {
        version = versionValue;
    }

    /**
     * This will get the version of this PDF document.
     *
     * @return This documents version.
     */
    public float getVersion()
    {
        return version;
    }

    /**
     * This will tell if this is an encrypted document.
     *
     * @return true If this document is encrypted.
     */
    public boolean isEncrypted()
    {
        boolean encrypted = false;
        if( trailer != null )
        {