1. JavaIOC Overview and Update
EPICS Meeting
INFN October
Presented by:
Marty Kraimer

2. EPICS Meeting: JavaIOC
Overview
Major changes in latest release
Simplified Database
Expression Calculator
VXI11 portDriver
Beginning of Hardware support
Not tested!!
Soon
STREAM protocol files and IP (Internet Protocol) support
When done than support message based devices: serial,gpib
Not discussed in this talk
See for documentation and download
But First an Overview for those who do not know what the JavaIOC is.
INFN October
EPICS Meeting: JavaIOC

3. EPICS Meeting: JavaIOC
JavaIOC – What Is It?
IOC - Input/Output Controller
Has a “smart” real time database
Record instances can be processed.
Records can be accessed via Channel Access.
Records can link to hardware, other records, etc.
Has functionality like an EPICS IOC but
Structured data
Better Array data
Generic Support
Written in Java
INFN October
EPICS Meeting: JavaIOC

4. EPICS Meeting: JavaIOC
Features
PV (Process Variable) Database
DB – Runtime Database that contains definitions for:
structure – Structure of fields
create – Name of factory for overriding default data implementation
support – Name of factory for support for a field
record – Record instance.
XML Parsers for DB
Record Processing and Monitoring
Record Scanning: Periodic and Event
Channel Access
Generic structure, create, and support definitions and implementation
INFN October
EPICS Meeting: JavaIOC

5. EPICS Meeting: JavaIOC
PV Database
Field types
Primitive: all Java primitives except char
boolean, byte, short, int, long, float, double
string: implemented as a Java String
structure: has fields. Each field can be any type
array: elementType can be any type
Complex Structures fully supported
Introspection and Data interfaces: Provide access to any field.
INFN October
EPICS Meeting: JavaIOC

6. EPICS Meeting: JavaIOC
PV Introspection
Introspection Interfaces, i.e. no data
Field: Methods: getType, getFieldName, ...
Array: extends Field: Method: getElementType
Structure: extends Field
Methods: getFields, getStructureName
FieldFactory
Implements introspection interfaces
Can be extended but probably not necessary
INFN October
EPICS Meeting: JavaIOC

7. EPICS Meeting: JavaIOC
PV Data Interfaces
PVField: Base for data: Methods: getField, ...
PVBoolean,...,PVString : Methods: get,put
PVArray: Base for array data interfaces
PVBooleanArray,...,PVArrayArray : Methods get,put
PVStructure provides access to a structure.
PVRecord provides access to a record instance.
PVDataFactory
Default implementation.
Any PVField can be replaced. Often useful
ConvertFactory: Convert between data types
INFN October
EPICS Meeting: JavaIOC

8. EPICS Meeting: JavaIOC
org.epics.ioc.pv
Self Contained Java package for PV Data
Can be used for purposes other than JavaIOC Database
Example: Channel Access Local and EPICS client use PV Data
It is designed to be used for other purposes.
Via structures it could support
Vector/Matrix Data
Image Data
etc.
INFN October
EPICS Meeting: JavaIOC

9. DB Database and Record Processing
DB Database provides
Record Locking – A record instance can be locked.
Ability to monitor puts to any field of a record instance.
Register and locate support for record and fields of a record.
Record Processing
Coordinates processing of a record instance.
Both synchronous and asynchronous processing are supported.
Each instance can have at most one record processor.
A record can be self processed. Simulates multiple processors.
Get and Put support
Can process after put. Also supported by EPICS.
Can process before get. Not supported by EPICS.
Can put, then process, then get. Not supported by EPICS.
INFN October
EPICS Meeting: JavaIOC

10. EPICS Meeting: JavaIOC
XML Parser
DB - Database Definitions
structure - a set of fields
create – names a factory that replaces default data implementation.
support – names a factory that implements support for a field.
record – record instance
Macro Substitution and Include
INFN October
EPICS Meeting: JavaIOC

11. EPICS Meeting: JavaIOC
Record Processing
A record instance is basic process unit
It is locked during any processing or I/O
RecordProcess is master. It calls support for record instance.
Support modules implement semantics
ANY field can optionally have support
Record instance must have support
No lock sets
INFN October
EPICS Meeting: JavaIOC

12. EPICS Meeting: JavaIOC
Record Scanning
Scan
Types: passive, periodic, event
Priority Uses Java priorities
Threads created as required
Periodic
Arbitrary rate: minPeriod,deltaPeriod
Event
Based on eventName
Replaces EPICS event and I/O Inter
INFN October
EPICS Meeting: JavaIOC

13. EPICS Meeting: JavaIOC
Support
Implements Record Processing Semantics
Each record instance has support
Each field can optionally have support
Support can call other support
Support provided with javaIOC is as generic as possible
During initialization looks for required fields and support
If required fields not found then does not start
Example: generic – support for a structure or array
Calls support for each sub field that has support
Each support must finish before next is called
Supports a structure or an array of arrays or structures
INFN October
EPICS Meeting: JavaIOC

14. EPICS Meeting: JavaIOC
Implemented
PV (Process Variable) Database
XML Parsers: DBD and Record Instance
Record Processing/Scanning/Monitoring
Channel Access
Channel Access Local
EPICS CA Server
EPICS CA Client
Generic record/structures and support
portDriver – JavaIOC implementation of ASYN Support
SWTSHELL: GUI iocshell
Expression Calculator – features like EPICS calc.
INFN October
EPICS Meeting: JavaIOC

15. EPICS Meeting: JavaIOC
Not Implemented
Replacement for EPICS sequencer.
JavaIOC Channel Access
Full Introspection and structure support for JavaIOC client <-> JavaIOC server
VDCT: Visual Database Configuration Tool
Access security
Error logging
???
Lots to do!!
BUT
It is ready for at least soft IOC Support and soon for serial, gpib, and vxi11.
INFN October
EPICS Meeting: JavaIOC

16. EPICS Meeting: JavaIOC
Simplified Database
Before latest release the following existed but no longer
RecordType – A top level structure for a record instance
DBD and DB XML syntax and databases
Extensive set of recordType definitions
Now
When creating a record instance new fields can be appended to existing structure.
This one feature made it possible to remove above features
Structure generic
Has no fields!!
The default support is generic.
Following slides show how record instances are created from generic.
INFN October
EPICS Meeting: JavaIOC

17. Really Simple Record Instance
<record name = "reallySimple” >
<value type = “double” />
</record>
which is the same as
<record name = "reallySimple” structureName = “generic” >
The above record instance
Has a single field named value of type double. This is the ONLY data associated with this record.
The field value is appended to generic which has no fields
The record can be processed but not much happens except monitoring
INFN October
EPICS Meeting: JavaIOC

18. Not So Simple Record Instance
<record name = "notQuiteAsSimple">
<value type = "double" />
<alarm structureName = "alarm" />
<timeStamp structureName = "timeStamp" />
<display structureName = "display" />
<input structureName = "inputSupport">
<pvname>somePV</pvname>
</input>
<scan structureName = "scan">
<type><choice>periodic</choice></type>
<rate>1.0</rate>
</scan>
</record>
The above record instance has the following fields
value – type is double
alarm data and support
timeStamp
display – display properties.
input – input is from another record. Could be EPICS V3 record
scan – The record is scanned once a second
INFN October
EPICS Meeting: JavaIOC

19. Really Simple Expression
<record name = "calcSimpleCounter" >
<value type = "int" />
<alarm structureName = "alarm" />
<timeStamp structureName = "timeStamp" />
<input structureName = "calculation" >
<calculator>
<expression>value+1</expression>
</calculator>
</input>
</record>
The above record instance
Has a field named value of type int.
Has fields alarm and timeStamp
Has a field input which performs a calculation
The calculator is expressionCalculator
The expression adds 1 to value each time record is processed
Note that value has type int
INFN October
EPICS Meeting: JavaIOC

20. EPICS Meeting: JavaIOC
Counter from 0 to 10
<record name = "calcSimpleCounter" >
<value type = "int" />
<alarm structureName = "alarm" />
<timeStamp structureName = "timeStamp" />
<input structureName = "calculation" >
<calculator>
<expression>value+1<=10?value+1:0</expression>
</calculator>
</input>
</record>
The above record instance
Expression is (value+1)<=10 ? (value+1) : 0
Like previous but counts from 0 to 10.
Note that because of xml syntax must use xml escape sequence for
< is <
> is >
& is &
INFN October
EPICS Meeting: JavaIOC

21. Counter With Named Arguments
<record name = "calcCounter">
<value type = "double” />
<input structureName = "calculation" >
<calcArgArray>
<element structureName = "calcArg">
<value type = "double">0.0</value>
<name>min</name>
</element>
<value type = "double">10.0</value>
<name>max</name>
<value type = "double">0.5</value>
<name>inc</name>
</calcArgArray>
<calculator>
<expression>((value+inc)<=max)?(value+inc):min</expression>
</calculator>
</input>
</record>
Example of expression with named arguments
Expression is ((value+inc)<=max) ? (value+inc) : min
INFN October
EPICS Meeting: JavaIOC

22. Expression Calculator Features
Syntax is a valid Java scalar expression
Operators
Binary + - * / % << >> >>>
Unary + - ~
Logical < <= > >= == !=
Bitwise & | ^
Conditional && ||
IfThenElse ?:
Result assigned to value field
All Java scalar types except char are supported
Boolean, byte, short, int, float, double
Arguments can be
Valid Java constant
value – The current value of the field named value
Variable – value is from calcArgArray element identified by name
All Java lang.Math functions and constants are supported
INFN October
EPICS Meeting: JavaIOC

23. EPICS Meeting: JavaIOC
Example Expressions
The following are all valid expressions:
A + b*(c+3.0) + Math.abs(d)‏
(register&~mask)|((desiredValue<<offset)&mask)‏
Means (register&~mask)|((desiredValue<<offset)&mask)‏
Updates bits specified by mask
Math.sin(2.0*Math.PI*position)‏
(a<b)&&(c>d) ? e : 0.0
Means (a<b)&&(c>d) ? e : 0.0
INFN October
EPICS Meeting: JavaIOC

24. Calculation Structure Definitions
<structure name = "calcArg" supportName = "generic" >
<!-- instance must define value -->
<field name = "name" type = "string" />
</structure>
<structure name = "expressionCalculator" supportName = "expressionCalculator" >
<field name = "expression" type = "string" />
<structure name = "calculation" supportName = "generic" >
<field name = "calcArgArray"
elementType = "structure" supportName = "calcArgArray" />
<field name = "calculator" structureName = "expressionCalculator" />
<field name = "alarm" structureName = "alarm" />
Calculation is the structure for a calculation
calcArgArray is an array of structures each of which must be a calcArg
CalcArg describes a single argument for the calculation
Name – the name of the argument that can be used in an expression
Value – Must be added in each instance and given a scalar type
Other fields can be defined
Calculator identifies support. Default is expressionCalculator.
INFN October
EPICS Meeting: JavaIOC

25. Example Argument Definition
<calcArgArray>
<element structureName = "calcArg">
<value type = "double">0.0</value>
<name>a</name>
</element>
<value type = "double"/>
<name>b</name>
<alarm structureName = “alarm”/>
<input supportName = "pdrvFloat64Input"
structureName = "pdrvSupport">
<portName>somePort</portName>
<deviceName>someDevice</deviceName>
</input>
</calcArgArray>
The first element assigns a value to the argument
A client could change the value.
The second element gets a value for the argument via a portDriver
This can be hardware
Can define other ways to get value. For example a link to another record.
INFN October
EPICS Meeting: JavaIOC