Skip to main content

Learning Dojo: Compression

By default, build compresses any packaged resources and does not compress any other resources. Both of these behaviros can be controlled by the command-line options layerOptimize( for packaged resources) and optimize( for all other resources). The possible values for these options are as follows.


  • "" Don't compress
  • shrinksafe: Use Dojo-Rhino to delete whitespace and comments and shorten variable names
  • shrinksafe.keeplines: Same as shrinksafe, but keep newlines.
  • packer: Use the Dean Edwards packer.
Whenever build compresses a resource, it writes both an uncompressed version to module-name.js.uncompressed.js and a compressed version to module-name.js

Compressing javaScript Resources with Dojo-Rhino
Dojo-Rhino walks a Rhino-generated parse tree and dumps compressed JavaScript code. The compression function can be called from the command line to compress an individual file. This technique for compressing JavaScript is both powerful and safe. Since the  routines that execute the compression are working off the parse tree, the compression is based on semantic algorithms rather than pattern matching. Consequently, obscure transformation errors are unlikely; this is not alway the case when the script is compressed by applying pattern matching algorithms.

The compression algorithms remove whitespace and comments and shorten variables names. This means that the output is still valid JavaScript source codes; specifically, there is no decompressor required to unpacke the source. The compression rate will vary greatly depending upon the input. 

Comments

Popular posts from this blog

Quicksort implementation by using Java

 source: http://www.algolist.net/Algorithms/Sorting/Quicksort. The divide-and-conquer strategy is used in quicksort. Below the recursion step is described: 1st: Choose a pivot value. We take the value of the middle element as pivot value, but it can be any value(e.g. some people would like to pick the first element and do the exchange in the end) 2nd: Partition. Rearrange elements in such a way, that all elements which are lesser than the pivot go to the left part of the array and all elements greater than the pivot, go to the right part of the array. Values equal to the pivot can stay in any part of the array. Apply quicksort algorithm recursively to the left and the right parts - the previous pivot element excluded! Partition algorithm in detail: There are two indices i and j and at the very beginning of the partition algorithm i points to the first element in the array and j points to the last one. Then algorithm moves i forward, until an element with value greater or equal

Live - solving the jasper report out of memory and high cpu usage problems

I still can not find the solution. So I summary all the things and tell my boss about it. If any one knows the solution, please let me know. Symptom: 1.        The JVM became Out of memory when creating big consumption report 2.        Those JRTemplateElement-instances is still there occupied even if I logged out the system Reason:         1. There is a large number of JRTemplateElement-instances cached in the memory 2.     The clearobjects() method in ReportThread class has not been triggered when logging out Action I tried:      About the Virtualizer: 1.     Replacing the JRSwapFileVirtualizer with JRFileVirtualizer 2.     Not use any FileVirtualizer for cache the report in the hard disk Result: The japserreport still creating the a large number of JRTemplateElement-instances in the memory        About the work around below,      I tried: item 3(in below work around list) – result: it helps to reduce  the size of the JRTemplateElement Object        

Stretch a row if data overflows in jasper reports

It is very common that some columns of the report need to stretch to show all the content in that column. But  if you just specify the property " stretch with overflow' to that column(we called text field in jasper report world) , it will just stretch that column and won't change other columns, so the row could be ridiculous. Haven't find the solution from internet yet. So I just review the properties in iReport one by one and find two useful properties(the bold  highlighted in example below) which resolve the problems.   example: <band height="20" splitType="Stretch" > <textField isStretchWithOverflow="true" pattern="" isBlankWhenNull="true"> <reportElement stretchType="RelativeToTallestObject" mode="Opaque" x="192" y="0" width="183" height="20"/> <box leftPadding="2"> <pen lineWidth="0.25"/>