Our BTree Product

Virtual Machinery offers a B+Tree implementation for the Java platform. The distribution comes with full documentation and example code. You can download a Demo of our BTree by clicking here. BTrees are also useful in J2EE - you can read more here and you can download the code associated with this discussion here . In the memory-constrained environment encountered on small devices that implement the Sun J2ME platform Virtual Machinery's implementation is invaluable. You can learn more about this here and download the demo application here.

Other items in the Distribution

• A set of classes which implement a BTree in the Micro Edition of Java (J2ME).This ME version of the BTree provides all the functionality of the original BTree product. The product has been designed for use with Version 2.5 of Sun's J2ME Wireless Toolkit and sample applications which work in this environment and the latest Sun J2ME SDK (3.0) environment are supplied. An extensive guide to the features can be found in the programmers guide.
• A set ofclasses which implement read-only BTrees. Using a read-only BTree gives performance and footprint benefits when used in place of a full BTree. Of course such BTrees are only suitable for use in situations where there is no requirement to modify the data contained in the tree. As a further extension to the Read Only BTree a Read Only Btree which is stored entirely in memory is also provided as a means to increase performance. The Read Only BTree classes are installed as part of the product installation. Two sample applications are supplied and an extensive guide to the features can be found in the programmers guide.

Advantages

• Fast access to textually keyed data (sub-millisecond access on most platforms when index and data are fully cached).
• Forward key compression allows use of meaningful keys with reduced space penalty.
• Transaction support with commit and rollback.
• User defined cache levels for both index and data pages.
• Full source code provided.
• Individual datasets can hold up to 4Gb of data.
• Set of diagnostic tools provided (runs on Windows only) - verify, compress and fix datasets.
• Design allows for single classes to be substituted e.g. to use a different type of cache.

Limitations

• Single process only.
• Key limited to 120 bytes.
• Maximum 64k data pages.
• Maximum 65024 byte page size.

The Standard Java BTree version can also be used without modification on Google's Android (TM) Mobile Platform.You can download a sample application that uses the implementation by clicking here

Further Information

A Quick guide to BTrees gives an overview of the underlying principles of BTrees.The QuickStart for Java page gives you a rapid introduction to creating and using this Btree implementation. A more extensive guide to the features is supplied with each distribution in the form of a Programmers guide. Full javadoc-generated class documentation is also available. For more information contact info@virtualmachinery.com.

You can find out more about our BTree implementation on the BTree FAQ page. We also have some BTree programming tips and tricks listed here which will show you how to make the most efficient use of BTrees in your application. We always welcome feedback on our product and demos - please feel free to contact us using the link at the bottom of the page.

Click here to buy Virtual Machinerys BTree implementation online.