Update README.md

Author: shroffk

gpclient/README.md

@@ -1,2 +1,38 @@
-# epicsVTypeJava
-A set of interfaces and utilities to work with EPICS types in Java
+# gpClient
+
+The generic purpose client is meant to be used to build applications that 
+are not specific to a particular deployment environment or to a particular use
+case. It provides a system of queuing and caching that is appropriate
+in most instances of multi-threaded applications. It isolates each reader
+and writer and therefore protects different parts of the applications.
+As such, it is not suitable for all purposes.
+
+
+You **WILL** want to use the gpclient if:
+	
+You want data access and do not care about protocol details  
+You want something thread-safe without having to care about locks and race conditions  
+You want to mix data from multiple sources (i.e. other protocols, databases, files, etc.)  
+You are developing a user interface  
+You are developing an extensible application where different user will
+want data access  
+
+  
+You may **NOT** want to use the gpclient if:
+
+You need low level access to the EPICS communication protocol  
+You need to implement an application specific real-time engine  
+You want to lock the protocol until you have processed the data  
+All your reads/write are tightly coupled to each other  
+
+
+The generic purpose client provides the following functionality:
+
+
+* A client API that is always thread-safe  
+the ability to specify on which thread or thread pool the notification
+should happen  
+* A pluggable way to connect to different publish/subscribe sources of
+data (i.e. {@link DataSource})  
+* The ability to create your own data channel implementations, even if
+they do not follow the common patterns