What is OpenEXI?
OpenEXI is an open source Java implementation of the W3C Efficient XML Interchange (EXI) format specification. As a corollary to XML, EXI is an alternative, very efficient format that has all of the mechanics of XML, but is much more compact and is faster to exchange and process.
The implementation effort is led by Fujitsu, NPS (Naval Postgraduate School) and OptimaLogic, in the hope that a solid open source implementation would give a head start in catalyzing EXI's adoption in many user communities.
OpenEXI is available for public use under Apache License, Version 2.0.
Why not simply use GZip instead of EXI?
Many use cases that need EXI not only exhibit the requirement to greatly improve the bandwidth usage, but also are found very conscious of the implications on the processing efficiency in encoding and decoding the files being exchanged. While gzip is often deemed useful to compress files to reduce file sizes, there are cases that the burden entailed in compressing then decompressing the files outweighs the benefit of the compression itself, rendering gzip not very realistic for use in such cases. EXI, on the other hand, serves quite well to reduce the file sizes even without exerting the compression, making EXI perform very fast in encoding and decoding the files. EXI includes the capability of compression (i.e. EXI compression) that can be explored when doing so further improves the total benefit of efficiency. EXI compression is found to perform much faster than gzip, and at the same time to be much more effective in reducing file sizes.
There are a relatively large class of EXI use cases that aspires to modernize legacy applications in order to make them more suitable for interacting with modern internet technologies such as the Web and XML. More often than not, these applications have been using packed binary formats to increase the efficiency of data exchanges. There are many application scenarios in which the information is exchanged very frequently, with each message that represents the individual exchange of information being fairly compact. Unfortunately, gzip does not necessarily perform well enough to make the use of XML realistic in those applications. There are even such cases that gzip makes the XML bigger after compression, despite of all the cost of computation involved in the compression and subsequent decompression. EXI not only consistently competes well with existing packed binary formats in terms of file compactness, but also is often found to surmount them . It is also worth noting that EXI consistently beats gzip in compactness across the board over a diverse set of data differing in sizes and complexity, collected from a wide range of use cases of which the ones described above are just a small part.
Project Status
OpenEXI is a full-fledged implementation of W3C EXI Recommendation except that it provides no support for selfContained option.
Download OpenEXI
Download OpenEXI from here.
External Links