Book Image

Oracle Coherence 3.5

By : Aleksandar Seovic
Book Image

Oracle Coherence 3.5

By: Aleksandar Seovic

Overview of this book

Scalability, performance, and reliability have to be designed into an application from the very beginning, as there may be substantial cost or implementation consequences if they need to be added down the line. This indispensible book will teach you how to achieve these things using Oracle Coherence, a leading data grid product on the market.Authored by leading Oracle Coherence authorities, this essential book will teach you how to use Oracle Coherence to build high-performance applications that scale to hundreds of machines and have no single points of failure. You will learn when and how to use Coherence features such as distributed caching, parallel processing, and real-time events within your application, and understand how Coherence fits into the overall application architecture. Oracle Coherence provides a solid architectural foundation for scalable, high-performance and highly available enterprise applications, through features such as distributed caching, parallel processing, distributed queries and aggregations, real-time events, and the elimination of single points of failure.However, in order to take full advantage of these features, you need to design your application for Coherence from the beginning. Based on the authors' extensive knowledge of Oracle Coherence, and how to use it in the real world, this book will provide you with all the information you need in order to leverage various Coherence features properly. It contains a collection of best practice-based solutions and mini-frameworks that will allow you to be more productive from the very beginning.The early chapters cover basics like installation guidelines and caching topologies, before moving on to the domain model implementation guidelines, distributed queries and aggregations, parallel processing, and real-time events. Towards the end, you learn how to integrate Coherence with different persistence technologies, how to access Coherence from platforms other than Java, and how to test and debug classes and applications that depend on Coherence.
Table of Contents (22 chapters)
Oracle Coherence 3.5
Credits
Foreword
About the author
Acknowledgements
About the co-authors
About the reviewers
Preface
12
The Right Tool for the Job
Index

Implementing read through


Enabling read through in Coherence requires the implementation of an interface called CacheLoader. The CacheLoader interface in its entirety is as follows:

public interface CacheLoader {
  Object load(Object key);
  Map loadAll(Collection keys);
}

The load method is responsible for retrieving the value from the database, based on the specified key. The loadAll method accepts a collection of keys that may be bulk loaded; it returns a map of the keys and their corresponding values loaded from the database. If one of the requested keys does not exist in the database, that key should be excluded from the result map. As can be observed via the key-based API, read through will only work with key-based access, that is, queries executed via the QueryMap API will not use CacheLoader.

Note

The loadAll method in CacheLoader will not be invoked by Coherence unless operation bundling is configured. This topic falls outside the scope of this book; however, this feature is documented...