Perst Embedded Database Upgrade Brings Full-Text Search and More to Mobile Phones
January 26, 2009 – McObject has released Perst 4.0, an upgrade to its open source, object-oriented embedded database system for smartphones and other Java-based mobile devices. In the new release, Perst extends its full-text search capability to new mobile device environments, and builds on this feature to provide a sample search engine application for phones based on Google’s Android platform as well as BlackBerry, Nokia and other Java ME-based mobile devices.
(Interested in more details on Perst? Check out the Perst section of this Web site, our concise 38-page Perst Introduction and Tutorial (PDF), or download the Perst software, with complete source code.)
For Perst Lite (the Java ME edition of Perst), the upgrade to version 4.0 adds seamless integration with the popular EclipseME integrated development environment, as well as improved handling of memory and storage.
In v. 4.0, Perst Lite also gains full-text search capability – a feature already present in the standard Perst edition used with Google’s Android. To provide search, the database stores an inverse index of keywords, with parsing and stemming of indexed text performed either by user-defined code or by Perst’s default simple parser and stemmer. The feature supports logical operators and calculates search results’ relevance to a query.
To illustrate the use of full-text search, Perst 4.0 includes a new sample application—called PIMindex for Java ME, and ContactsIndex for Android—demonstrating a local search engine on mobile devices. The example application stores and indexes contact information, and could be extended to provide search capabilities for PDF, word processing, HTML and other stored files. Both PIMindex and ContactsIndex are included in the Perst 4.0 for Java distribution (which also includes both Perst and Perst Lite), with complete source code.
Perst Lite 4.0 has also been updated to work with EclipseME, the Java ME plug-in to IBM’s popular free Eclipse development framework. Perst Lite now includes a sample EclipseME project in its ProScout example application. With the enhancements, Perst Lite supports developers in building Java ME applications (midlets) under EclipseME as part of software packages to be uploaded into devices–adding embedded database capabilities to the list of software features that can go “From zero to mobile in minutes,” in the words of the EclipseME project (http://eclipseme.org).
In addition to EclipseME support, Perst Lite 4.0 includes these enhancements:
- Automatic determination of storage type. Perst Lite now chooses the correct storage layer implementation from among Java ME Connected Device Configuration (CDC) file interfaces: JSR-75, which allows access to file systems on certain devices; or Java ME’s Record Management System (RMS) persistent storage mechanism.
- Support for “weak references.” This simplifies the object caching process by allowing objects to be claimed by Java ME’s garbage collection, thus eliminating the need for developers to explicitly control cache size.
Perst 4.0 also greatly broadens the object types addressed by the embedded database. Past versions enabled developers to create and manage Java and .NET objects derived from the database system’s Persistent class, while benefiting from Perst’s high performance, small footprint, and features such as ACID (Atomic, Consistent, Isolated and Durable) transactions, a SQL-like interface and specialized collections classes.
In version 4.0, “foreign” objects or objects derived from any class can be stored in the database, vastly increasing Perst’s usability with external programs. As a result, Perst can be added as storage for existing applications such as commercial or open source class frameworks, including GUI classes, object-request brokers, and industry-specific solutions; UML modeling tools that generate classes from wizards; and programs whose source code is not available.
Perst 4.0 for Java and .NET, with full source code, can be downloaded from https://www.mcobject.com/perst_eval.
Founded by embedded database and real-time systems experts, McObject offers proven data management technology that makes applications and devices smarter, more reliable and more cost-effective to develop and maintain. McObject counts among its customers industry leaders such as Chrysler, Maximizer Software, Siemens, Phillips, EADS, JVC, Tyco Thermal Controls, F5 Networks, DIRECTV, CA, Motorola and Boeing. McObject, based in Issaquah, WA, is committed to providing innovative technology and first-rate services to customers and partners. The company can be reached at +1-425-888-8505, or visit www.mcobject.com.
McObject and eXtremeDB are trademarks or registered trademarks of McObject LLC. All other company or product names mentioned herein are trademarks or registered trademarks of their respective owners.