javaioc status epics meeting icalepcs2009 kobe japan marty kraimer and matej sekoranja

JavaIOC Status

EPICS Meeting ICALEPCS2009Kobe Japan

Marty Kraimer And Matej Sekoranja

Kobe Japan Oct 2009 ICALEPCS EPICS Meeting: javaIOC 2

Outline of Talk What is javaIOC?

New features since Vancouver EPICS meeting

Overview of pvData Overview of javaIOC Examples of VDCT in action CAJv4 – Channel Access for Java Version 4


JavaIOC: What is it? EPICS IOC record has

flat structure – VAL plus other fields channel access – value, alarm, timeStamp, display, control dbCommon – support handled by dbAccess, etc. DTYP, INP/OUT – support done by device support recordType – support for all other fields done by record support

JavaIOC record has structured data – record can be a device. example is a power supply channel access – full support for structure data structures

standard: alarm, timeStamp, display, control extensible – can be application specific but supported by CA

support – no distinction between record and device support any field can optionally have associated support standard: alarm, timeStamp, linearConvert, digital, etc extensible – Can be used wherever appropriate

PVData has many other possible uses


Example Record Instances

<record name = "valueOnly"> <scalar name = "value" scalarType = "double">1.0</scalar></record>

<record name = "valueAlarmTimeStamp"> <scalar name = "value" scalarType = "double"/> <structure name = "alarm" extends = "alarm" /> <structure name = "timeStamp" extends = "timeStamp" /></record>

<record name = "aiExample"> <scalar name = "value" scalarType = "double"/> <structure name = "alarm" extends = "alarm" /> <structure name = "timeStamp" extends = "timeStamp" /> <structure name = "link" extends = "caInputLink"> <scalar name = "pvname">somePV</scalar> </structure></record>


Example Record: Power Supply

Additional fields may also be present.

powerSupply alarm timeStamp power value alarm voltage value alarm input ... current value alarm output ...


Main New Features

CHANNEL ACCESS!!! Full network support for pvData CAJv4 implemented by Matej Two new packages for pvData: pvCopy and monitor.

VDCT!! Implemented by Janez Golob and Jernej Fesel Kamenick (CosyLab)

Special Thanks to: Bob Dalesio for support, advice, and encouragement Guobao Shen (BNL) who is implementing first High Level

Implementation. Talk later today. Sheng Peng (SLAC) who is defining structures and implementing

support that is similar to the recordTypes in EPICS base.


epics-pvdata EPICS-pvdata is a Source Forge Project (sourceforge.net)

PVData is being developed as eclipse projects pvData – memory resident database – records have structured data CAJv4 – Channel Access for Java Version 4 javaIOC – Record Processing and Optional Support for fields Others – Not discussed in this talk

A link in the sourceforge summary provides: An overview of EPICS-pvData. Links to the javaDoc for pvData, CAJv4, and javaIOC.

Each eclipse project has a project overview. Many eclipse packages have a package overview.

Release 0.8.0 is available. Instructions for importing as eclipse projects. .8 means that most functionality implemented and lots of testing has

been done. 0.8 means that future 0.x.x releases will not guarantee compatibility


pvData PVDatabase – Memory Resident Database of PVRecords. PVRecord – Is a top level PVStructure. PVStructure – Is a structured set of PVFields. PVField

Has a type : scalar, array, or structure. Contains data. Has code for accessing data and for introspection.

Accessed via Java interfaces Any field of any record can be monitored for puts. New since Vancouver.

New package pvCopy. Copy of an arbitrary subset of the fields in a PVRecord. Optionally share the data from the PVRecord.

New package monitor. Extensible monitor implementation


New pvData packages that support caV4 org.epics.pvData.pvCopy

PVCopy – An interface for a PVStructure. Accesses an arbitrary subset of the fields in a PVRecord. Can optionally share the data from the PVRecord.

PVCopyMonitor – An interface for monitoring a PVRecord. Updates the fields in PVCopy. Updates two BitSets (a bit per field): change and overrun.

org.epics.pvData.monitor Monitor Queue

Client chooses queue size 0 no queue and share data with record 1 no queue but single copy >=2 queue size

Monitor Algorithm Identified by name Provided: onPut, onChange, onAbsoluteChange,onPercentChange Extensible Implementation

Registers during initialization.


javaIOC Main Features:

A record can be processed. Each field can optionally have associated support. PortDriver is java implementation of asynDriver.

Almost no low level driver support. Thus not ready. swtshell - Standard Widget Toolkit shell for a javaIOC.

Full support for channel access. Changes since Vancouver.

Only channel access related changes. org.epics.ioc.ca - Old definitions for channel access.

Deleted In CAJv4 Very different. Lighter weight.


VDCT VDCT - Visual Database Configuration Tool based on Java NetBeans Visual Library generic data model, support for EPICS V3 and V4 implemented 'standard' GUI features: clipboard, undo/redo, drag & drop, etc. views: graphical, property (inspector), spreadsheet, tree customizable record shapes and colors (CapFast-like shapes implemented) file-system and basic IRMIS support Next four slides show VDCT in action


EPICS V4 Record


V4 Hierarchy


EPICS V3 Record


V3 Spread Sheet


Channel Access Overview Eclipse project CAJv4

Full support for pvData. Depends only on project pvData. Three components can be started by an application.

ClientFactory.start() - client side of network support. LocalFactory.start() - access local PVDatabase. ServerFactory.start() - server side of network support.

org.epics.ioc.caV3 ( In javaIOC; May become separate eclipse project) Has been available for couple of years. Client support

Allows a pvData client to access EPICS V3 Data. Server support

Allows an EPICS V3 CA client to access a PVDatabase. Other Channel Providers can be registered.

Gateways to/from other data sources. An application can start all of the above.


Connecting to a Channel ChannelAccessFactory returns ChannelAccess. Given a provider name ChannelAccess returns the ChannelProvider.

providers local, caV3, and caV4 are implemented Given a channel name ChannelProvider creates a Channel. A Channel connects the client to a PVRecord.


Channel Methods destroy – Disconnect and clean up. utility

isConnected, getChannelName, ... introspection

getField – shown on next slide Creation - Create once. Request may times without object creation.

createChannelProcess – process a record. createChannelGet – get data from a record. createChannelPut – put data to a record. createChannelPutGet – put followed by get createMonitor - monitor a record. createChannelArray – get/put sub-array.

Remainder of talk shows introspection, get, and, putGet.


Introspection

Client calls channel.getField.

channel.getField(this,null) - get introspection interface for record.

channel.getField(this,”value”) - get introspection interface for value.

channel.getfield(this,”display.limit”) - can get subfields. Client implements GetFieldRequester.

getDone returns status – next slide field – The introspection interface.

//interface Channel has method void getField(GetFieldRequester requester,String subField);// client implementspublic interface GetFieldRequester extends Requester { void getDone(Status status,Field field);}


Status Methods report success/failure via interface Status

Defined in pvData.pv Status type is one of OK,WARNING,ERROR,FATAL Methods provide

The status type An optional message string An optional stack dump isOK

Status is a singleton, i. e. no object creation for success. This is normal return value.

isSuccess


Get Semantics


createChannelGet arguments channelGetRequester – implemented by client. Methods are:

channelGetConnect - called after ChannelGet is created by server getDone - called when a get completes. Get is a method of ChannelGet

pvRequest – next slide. structureName – name given to PVStructure created for client. shareData – Should server share data with the PVRecord.

for arrays can save memory. for display managers good enough.

process process record before getting data.

pvOption for a client to pass extra information to a server. client and server must agree on structure. can be null for most except createMonitor.


pvRequest structure Defines the set of fields to which to connect. Client must create this. Not trivial!! Can create via xml definition or pvData factory BUT there is also an easier way. ChannelAccess has a method which

accepts a string argument and returns a pvRequest structure. Examples: ”value,alarm,display”

This attaches to top level fields with the same names The following request gets the following from a power supply record:

alarm and timeStamp from the record and value and alarm for the power, voltage, and current.

"alarm,timeStamp" + ",power{power.value,power.alarm}" + ",current{current.value,current.alarm}" + ",voltage{voltage.value,voltage.alarm}");


channelPutGet This does a put, an optional process, and a get. A javaIOC has a set of RPC (Remote Procedure Call) records.

Each has a structure named arguments. Each has a support that implements the RPC semantics. Each has a structure named result which hold the result data.

recordListRPC argument is a regular expression. result is the names of all the records that match.

iocShowRPC argument is a command that defines what to show. result depends on command.

recordShowRPC arguments are a record name and command. result depends on command.


Important Remaining Tasks Access Security

Not Implemented. A complication is that a channel does not attach to a single field.

Query Facility Nothing has been implemented.

TCP Transport Currently sender asks for network buffer, puts data, releases

Can not send more than fits in a network buffer. Will be changed

Sender queues request to send. Gets exclusive access to network port. Can issue multiple sends.

Serialization will be changed. It can trigger network send. No need for big network buffers just use MTU of network.

javaioc status epics meeting icalepcs2009 kobe japan marty kraimer and matej sekoranja

Documents

overview of epics

somepv icalepcs epics

epics base

record supportjavaioc

javaioc record processing

hasstructured data record

inpout support

optional support