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PDF renderer implementation supporting the subset of PDF 1.4 specification.
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/*
* $Id: Cache.java,v 1.4 2009/02/12 13:53:56 tomoke Exp $
*
* Copyright 2004 Sun Microsystems, Inc., 4150 Network Circle,
* Santa Clara, California 95054, U.S.A. All rights reserved.
*
* 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.sun.pdfview;
import java.awt.image.BufferedImage;
import java.lang.ref.SoftReference;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
/**
* A cache of PDF pages and images.
*/
public class Cache {
/** the pages in the cache, mapped by page number */
private Map pages;
/** Creates a new instance of a Cache */
public Cache() {
pages = Collections.synchronizedMap(new HashMap());
}
/**
* Add a page to the cache. This method should be used for
* pages which have already been completely rendered.
*
* @param pageNumber the page number of this page
* @param page the page to add
*/
public void addPage(Integer pageNumber, PDFPage page) {
addPageRecord(pageNumber, page, null);
}
/**
* Add a page to the cache. This method should be used for
* pages which are still in the process of being rendered.
*
* @param pageNumber the page number of this page
* @param page the page to add
* @param parser the parser which is parsing this page
*/
public void addPage(Integer pageNumber, PDFPage page, PDFParser parser) {
addPageRecord(pageNumber, page, parser);
}
/**
* Add an image to the cache. This method should be used for images
* which have already been completely rendered
*
* @param page page this image is associated with
* @param info the image info associated with this image
* @param image the image to add
*/
public void addImage(PDFPage page, ImageInfo info, BufferedImage image) {
addImageRecord(page, info, image, null);
}
/**
* Add an image to the cache. This method should be used for images
* which are still in the process of being rendered.
*
* @param page the page this image is associated with
* @param info the image info associated with this image
* @param image the image to add
* @param renderer the renderer which is rendering this page
*/
public void addImage(PDFPage page, ImageInfo info, BufferedImage image,
PDFRenderer renderer) {
addImageRecord(page, info, image, renderer);
}
/**
* Get a page from the cache
*
* @param pageNumber the number of the page to get
* @return the page, if it is in the cache, or null if not
*/
public PDFPage getPage(Integer pageNumber) {
PageRecord rec = getPageRecord(pageNumber);
if (rec != null) {
return (PDFPage) rec.value;
}
// not found
return null;
}
/**
* Get a page's parser from the cache
*
* @param pageNumber the number of the page to get the parser for
* @return the parser, or null if it is not in the cache
*/
public PDFParser getPageParser(Integer pageNumber) {
PageRecord rec = getPageRecord(pageNumber);
if (rec != null) {
return (PDFParser) rec.generator;
}
// not found
return null;
}
/**
* Get an image from the cache
*
* @param page the page the image is associated with
* @param info the image info that describes the image
*
* @return the image if it is in the cache, or null if not
*/
public BufferedImage getImage(PDFPage page, ImageInfo info) {
Record rec = getImageRecord(page, info);
if (rec != null) {
return (BufferedImage) rec.value;
}
// not found
return null;
}
/**
* Get an image's renderer from the cache
*
* @param page the page this image was generated from
* @param info the image info describing the image
* @return the renderer, or null if it is not in the cache
*/
public PDFRenderer getImageRenderer(PDFPage page, ImageInfo info) {
Record rec = getImageRecord(page, info);
if (rec != null) {
return (PDFRenderer) rec.generator;
}
// not found
return null;
}
/**
* Remove a page and all its associated images, as well as its parser
* and renderers, from the cache
*
* @param pageNumber the number of the page to remove
*/
public void removePage(Integer pageNumber) {
removePageRecord(pageNumber);
}
/**
* Remove an image and its associated renderer from the cache
*
* @param page the page the image is generated from
* @param info the image info of the image to remove
*/
public void removeImage(PDFPage page, ImageInfo info) {
removeImageRecord(page, info);
}
/**
* The internal routine to add a page to the cache, and return the
* page record which was generated
*/
PageRecord addPageRecord(Integer pageNumber, PDFPage page,
PDFParser parser) {
PageRecord rec = new PageRecord();
rec.value = page;
rec.generator = parser;
pages.put(pageNumber, new SoftReference(rec));
return rec;
}
/**
* Get a page's record from the cache
*
* @return the record, or null if it's not in the cache
*/
PageRecord getPageRecord(Integer pageNumber) {
// System.out.println("Request for page " + pageNumber);
SoftReference ref = pages.get(pageNumber);
if (ref != null) {
String val = (ref.get() == null) ? " not in " : " in ";
// System.out.println("Page " + pageNumber + val + "cache");
return (PageRecord) ref.get();
}
// System.out.println("Page " + pageNumber + " not in cache");
// not in cache
return null;
}
/**
* Remove a page's record from the cache
*/
PageRecord removePageRecord(Integer pageNumber) {
SoftReference ref = pages.remove(pageNumber);
if (ref != null) {
return (PageRecord) ref.get();
}
// not in cache
return null;
}
/**
* The internal routine to add an image to the cache and return the
* record that was generated.
*/
Record addImageRecord(PDFPage page, ImageInfo info,
BufferedImage image, PDFRenderer renderer) {
// first, find or create the relevant page record
Integer pageNumber = new Integer(page.getPageNumber());
PageRecord pageRec = getPageRecord(pageNumber);
if (pageRec == null) {
pageRec = addPageRecord(pageNumber, page, null);
}
// next, create the image record
Record rec = new Record();
rec.value = image;
rec.generator = renderer;
// add it to the cache
pageRec.images.put(info, new SoftReference(rec));
return rec;
}
/**
* Get an image's record from the cache
*
* @return the record, or null if it's not in the cache
*/
Record getImageRecord(PDFPage page, ImageInfo info) {
// first find the relevant page record
Integer pageNumber = new Integer(page.getPageNumber());
// System.out.println("Request for image on page " + pageNumber);
PageRecord pageRec = getPageRecord(pageNumber);
if (pageRec != null) {
SoftReference ref = pageRec.images.get(info);
if (ref != null) {
String val = (ref.get() == null) ? " not in " : " in ";
// System.out.println("Image on page " + pageNumber + val + " cache");
return (Record) ref.get();
}
}
// System.out.println("Image on page " + pageNumber + " not in cache");
// not found
return null;
}
/**
* Remove an image's record from the cache
*/
Record removeImageRecord(PDFPage page, ImageInfo info) {
// first find the relevant page record
Integer pageNumber = new Integer(page.getPageNumber());
PageRecord pageRec = getPageRecord(pageNumber);
if (pageRec != null) {
SoftReference ref = pageRec.images.remove(info);
if (ref != null) {
return (Record) ref.get();
}
}
return null;
}
/** the basic information about a page or image */
class Record {
/** the page or image itself */
Object value;
/** the thing generating the page, or null if done/not provided */
BaseWatchable generator;
}
/** the record stored for each page in the cache */
class PageRecord extends Record {
/** any images associated with the page */
Map> images;
/** create a new page record */
public PageRecord() {
images = Collections.synchronizedMap(new HashMap>());
}
}
}