On Tue, Apr 18, 2006 at 07:39:44PM -0500, a a wrote: > some one can explain me for what is > > public JRFileVirtualizer(int maxSize, > java.lang.String directory) > > Parameters: > maxSize - the maximum size (in JRVirtualizable > objects) of the paged in cache. > directory - the base directory in the filesystem > where the paged out data is to be stored
The maxSize parameter specifies how many of the JRPrintPage objects are kept in memory. The rest are virtualized to separate files in the temp directory. For example, if the report ended up taking 5000 pages, and maxSize was set to 100, then only 100 of the JRPrintPage objects would actually be held in memory, and the rest would be virtualized to the filesystem using a least-recently-used caching algorithm. If you can increase the heap size of your Java VM with the -Xmx400m switch for example (to give a max of 400Megabytes to the JVM), and keep the maxSize large, say around 250, then you will avoid virtualizing any pages as long as the report does not have more than 250 pages. This will speed up the creation of the JasperPrint object becuase it will not need to serialiize and deserialize all of the elements on the virtualized pages. > which are the cache page? > > which better for to spend less memory, use a > JRFileVirtualizer with a JasperPrint in memory object, > and after call > > JasperExportManager.exportReportToHtmlFile(jasperPrint,tmpFile.getPath()); > > or is better not use JRFileVirtualizer, and > > create the jasperPrint into a file and atfer export > from the file to create the report? I'm not sure whether creating a jasperPrint object into a file will really keep the object from being created in memory before it is sent to a file. If the JasperPrint object is created in memory first, then you would want to use the virtualizer to create the JapserPrint object whether or not you write it to a file. (Sorry, I don't know the answer to this without looking at the Jasper code.) Cheers, John -- "I'm a tenth level Vice President!" - Al Gore (Futurama) NOTICE: This message and any information, files or materials sent with may contain confidential and proprietary information or material of the sender, the recipient(s) or others, or information or material covered by the attorney-client privilege, attorney work product privilege, or other applicable privilege. If you are not a named recipient or if you have received this message in error, please notify the sender immediately by return email, delete this email from your system, and do not disclose the contents of this transmission to any other person, use this transmission or any of its contents for any purpose, or further copy its contents. Persons communicating with Works Operating Company, any of its affiliated companies, or any of their respective representatives by electronic means are advised and agree that such communications are reviewed for harmful or objectionable content or material. ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ jasperreports-questions mailing list jasperreports-questions@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/jasperreports-questions
