Portland, Ore. – Perst 4.0 is McObject's latest upgrade of its open source, object-oriented embedded database for Java and .NET. It adds persistence to any object—including objects created by other programs, those for which source code is unavailable, and objects created in different programming languages.
Perst 4.0 also adds new tools for developing mobile and embedded applications in both Java ME and in Google's Android environment. For Perst Lite (the Java ME edition of Perst), version 4.0 adds integration with the popular EclipseME integrated development environment, as well as improved handling of memory and storage.
The upgrade also adds full-text search capability. To illustrate the use of full-text search, the release includes a new sample application with full source code, demonstrating a local search engine that indexes and retrieves contact information stored on Java ME- and Android-based mobile phones.
Past versions of Perst enabled developers to create and manage Java and .NET objects derived from the database system's Persistent class, with 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, 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's enhancements for mobile and embedded application developers include a new example application—called PIMindex for Java ME, and ContactsIndex for Android—that builds on the embedded database's full-text search to provide a local search engine for contact management files on a cell phone or other device.
The example software – which is provided with full source code – 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).
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.
Perst Lite 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. This feature supports logical operators and calculates search results' relevance to a query.
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” 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 for Java and .NET, with full source code, can be downloaded from http://www.mcobject.com/perst_eval.