Interested in providing full-text search along with fast, lightweight data management for your Android applications? The new Perst 4.0 open source, object-oriented embedded database system brings native full-text search capability to Android, and builds on this feature to provide a sample search engine application for contact data residing on mobile phones.

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 relevance of search results to a query.

The new sample application for Android, ContactsIndex, stores and indexes contact information, and could be extended to provide search capabilities for PDF, word processing, HTML and other stored files. The example application is included with complete source code in the Perst 4.0 for Java distribution.

Also new in Perst 4.0 for Android: support for non-native objects, which expands the scope of the embedded database to benefit a larger variety of application types.

The Perst embedded database system helps developers create small-footprint embedded Java applications for Android that are fast, reliable, and cost-effective to develop and maintain.

The complete announcement of what’s new in Perst 4.0 is available at

http://www.mcobject.com/perst_v4_for_mobile_phones

Below some screenshots of the ContactsIndex demo application, running on the latest Android emulator.

McObject has added support for the KD-Tree, a database index with uses in spatial and pattern-matching applications, to its Perst open source, object-oriented embedded database system available for the Android mobile development platform.

The new k-dimensional tree or KD-Tree index adds a structure in Perst that stores and manipulates point objects in a k-dimensional space by partitioning that space. Practical uses include computer graphics, geographical information systems and biometric applications such as fingerprint matching. In addition to their efficiency in handling multi-dimensional data, KD-trees are useful in “normal” applications in which query predicates contain various combinations of object fields. For example, KD-Trees are used to construct Query-By-Example (QBE) features in which the user selects fields and values, and the application builds database queries based on these selections.

While many Java databases offer limited index support, Perst implements rich options for data access, including specialized collection classes optimized for different data layouts and access patterns, including:

• Classic B-Tree implementation;
• R-tree indexes for spatially-oriented applications such as GIS and navigation;
• Main-memory database containers, based on T-Tree indexes, optimized for real-time memory-only access;
• Patricia Trie index, which speeds searches in networking and telephony applications;
• TimeSeries class to efficiently deal with small fixed-size objects;
• Specialized versions of collections for thick indices (indices with many duplicates), and bit indices (keys with a restricted number of possible values);
• KD-Tree indexes

For McObject’s announcement of KD-Tree support see http://www.mcobject.com/pressroom.php?step=3&article=93.

For general information about Perst for Android, including links to the open source, complete Perst database source code, and to McObject’s Android-ready TestIndex database benchmark, go to http://www.mcobject.com/android/.

McObject announced today that Perst, its all-Java object-oriented, open source embedded database, has been verified as compatible with the Android mobile device platform backed by Google and the Open Handset Alliance.

McObject is offering the Android-ready Perst, as well as TestIndex, a demo application showing Perst and Android’s bundled SQLite database performing the same tasks side by side. Both are available as free downloads, with complete source code, from http://www.mcobject.com/android.

With Perst, users of Android-based phones will benefit from responsive, richly-featured embedded software made possible by a database system that delivers high performance and a small footprint, and by the efficiency that results from true Java developer-oriented features.

Perst stores data directly in Java objects. This eliminates the need for data-packing or unpacking code to map between the application’s data model and the database’s data model, as is required by relational and object-relational databases. The Perst API is flexible, easy-to-use and very fast compared to alternative commercial Java OODBMSs.

Perst is a very compact embedded database, with a core consisting of only five thousand lines of code. This small footprint imposes little demand on system resources. Moreover, Perst does not require administration. Perst supports transactions with the ACID (Atomic, Consistent, Isolated and Durable) properties, and expands developers’ coding efficiency by making Java objects as easy to use as possible.

For example, for access to objects, Perst implements specialized collection classes optimized for different data layouts and access patterns, including:

• Classic B-Tree implementation;
• R-tree indexes for spatially-oriented applications such as GIS and navigation;
• Main-memory database containers, based on T-Tree indexes, optimized for real-time memory-only access;
• Patricia Trie index, which speeds searches in networking and telephony applications;
• TimeSeries class to efficiently deal with small fixed-size objects;
• Specialized versions of collections for thick indices (indices with many duplicates), and bit indices (keys with a restricted number of possible values).

In addition to its core functionality, Perst provides optional features such as garbage collection, detection of hanging references, automatic schema evolution, XML import/export utilities, master-slave replication support (with the option to run read-only queries on slave nodes), an SQL subset to filter elements of any collection, and integration with the AspectJ and JAssist AOP tools.

To read McObject’s complete announcement of Perst and TestIndex for Android, see http://www.mcobject.com/pressroom.php?step=3&article=91.