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iText, a free Java-PDF library
/*
* $Id: PRIndirectReference.java 3721 2009-02-24 20:32:32Z mstorer $
*
* Copyright 2001, 2002 by Paulo Soares.
*
* The contents of this file are subject to the Mozilla Public License Version 1.1
* (the "License"); you may not use this file except in compliance with the License.
* You may obtain a copy of the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the License.
*
* The Original Code is 'iText, a free JAVA-PDF library'.
*
* The Initial Developer of the Original Code is Bruno Lowagie. Portions created by
* the Initial Developer are Copyright (C) 1999, 2000, 2001, 2002 by Bruno Lowagie.
* All Rights Reserved.
* Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer
* are Copyright (C) 2000, 2001, 2002 by Paulo Soares. All Rights Reserved.
*
* Contributor(s): all the names of the contributors are added in the source code
* where applicable.
*
* Alternatively, the contents of this file may be used under the terms of the
* LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the
* provisions of LGPL are applicable instead of those above. If you wish to
* allow use of your version of this file only under the terms of the LGPL
* License and not to allow others to use your version of this file under
* the MPL, indicate your decision by deleting the provisions above and
* replace them with the notice and other provisions required by the LGPL.
* If you do not delete the provisions above, a recipient may use your version
* of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE.
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the MPL as stated above or under the terms of the GNU
* Library General Public License as published by the Free Software Foundation;
* either version 2 of the License, or 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 Library general Public License for more
* details.
*
* If you didn't download this code from the following link, you should check if
* you aren't using an obsolete version:
* http://www.lowagie.com/iText/
*/
package com.lowagie.text.pdf;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.ref.WeakReference;
public class PRIndirectReference extends PdfIndirectReference {
protected PdfReader reader;
// membervariables
/**
* Used when 'reader' is "non-partial", holding the entire PDF in memory.
* Otherwise, we stick to PdfIndirectReference's "reffedObj".
* @since 2.1.5
*/
protected PdfObject hardReference;
// constructors
/**
* Constructs a PdfIndirectReference.
*
* @param reader a PdfReader
* @param number the object number.
* @param generation the generation number.
*/
PRIndirectReference(PdfReader reader, int number, int generation) {
type = INDIRECT;
this.number = number;
this.generation = generation;
this.reader = reader;
}
/**
* Constructs a PdfIndirectReference.
*
* @param reader a PdfReader
* @param number the object number.
*/
PRIndirectReference(PdfReader reader, int number) {
this(reader, number, 0);
}
// methods
public void toPdf(PdfWriter writer, OutputStream os) throws IOException {
int n = writer.getNewObjectNumber(reader, number, generation);
os.write(PdfEncodings.convertToBytes(new StringBuffer().append(n).append(" 0 R").toString(), null));
}
public PdfReader getReader() {
return reader;
}
public void setNumber(int number, int generation) {
this.number = number;
this.generation = generation;
// blow out any previous internal object storage.
hardReference = null;
reffedObj = null;
}
/**
* Find the direct object for this reference. It'll look up
* the correct one from its PdfReader if need be, but prefers to use
* the internally stored PdfObject.
* @return the direct object for this reference.
* @since 2.1.5
*/
public PdfObject getDirectObject() {
PdfObject dirObj = getInternalObject();
if (dirObj == null) {
dirObj = reader.getPdfObject(number);
if (reader.isPartial()) {
// weak references are ignored for purposes of GC
reffedObj = new WeakReference(dirObj);
reader.releaseLastXrefPartial();
hardReference = null;
}
else {
reffedObj = null;
hardReference = dirObj;
}
}
return dirObj;
}
/**
* Sorts out the current reference from either of the two
* places it could be stored.
* @return a valid object reference if there's one to get
* @since 2.1.5
*/
private PdfObject getInternalObject() {
if (hardReference == null && (reffedObj == null || reffedObj.get() == null)) {
return null;
}
return (hardReference != null) ? hardReference : (PdfObject) reffedObj.get();
}
/**
* Block alteration of a PRIndRef's direct object.
* @param obj ignored
* @since 2.1.5
*/
public void setDirectObject( PdfObject obj) {
}
}