I am looking for a way to read a tag’s value form inside a AbstractVisionPanel.
I have tried using “getAppContext().getTagManager().getTag()” but I am not sure if this is the right way 
. If it is, could you leave an example of getTag? I would greatly appreciation it 
Hi,
Yes, I think you’re close, I’d just use the read() function on the tag manager. It takes a list of tag paths, so if you don’t have those, you can use TagPathParser#parse to build them. In the client, a blank source means “project default”, so you could do something like:
QualifiedValue value = getAppContext().getTagManager().read(Arrays.asList(TagPathParser.parse("", "my/tag"))).get(0)I highly doubt you’d have a tag path hard coded in your component, but that would read it.
Regards,
I have copied your line of code, but my IDE and Maven keep showing java.io.IOException; must be caught or declared to be thrown. On the TagPathParser.parse call Not sure what I could be missing.
I am trying to call this in an AbstractVisionComponent.
That's your IDE enforcing java's exception handling. Add a throws clause to your containing method or catch the parse errors within the method.
I neglected to mention I did do that yesterday, and now it will build a .modl but I’m getting a stack trace now with the error Unable to locate function 'SQLTags.read' ... Here is some of the trace:
Exception in thread "AWT-EventQueue-2" java.lang.RuntimeException: com.inductiveautomation.ignition.client.gateway_interface.GatewayException: Unable to locate function 'SQLTags.read'
at com.inductiveautomation.ignition.client.sqltags.impl.db.DatasourceTagManager.read(DatasourceTagManager.java:436)
at com.inductiveautomation.ignition.client.sqltags.impl.ClientTagManagerImpl.read(ClientTagManagerImpl.java:192)
That isn’t enough context. Please show the whole error and the code of the method where it occurs.
Exception in thread "AWT-EventQueue-2" java.lang.RuntimeException: com.inductiveautomation.ignition.client.gateway_interface.GatewayException: Unable to locate function 'SQLTags.read'
at com.inductiveautomation.ignition.client.sqltags.impl.db.DatasourceTagManager.read(DatasourceTagManager.java:436)
at com.inductiveautomation.ignition.client.sqltags.impl.ClientTagManagerImpl.read(ClientTagManagerImpl.java:192)
at com.inductiveautomation.ignition.examples.ce.components.StandardTank.drawTag(StandardTank.java:103)
at com.inductiveautomation.ignition.examples.ce.components.StandardTank.paintComponent(StandardTank.java:91)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at com.inductiveautomation.vision.api.client.components.model.AbstractVisionPanel.paintChildren(AbstractVisionPanel.java:279)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at com.inductiveautomation.vision.api.client.components.model.AbstractVisionPanel.paintChildren(AbstractVisionPanel.java:279)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at com.inductiveautomation.vision.api.client.components.model.AbstractVisionPanel.paintChildren(AbstractVisionPanel.java:279)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at com.inductiveautomation.vision.api.client.components.model.AbstractVisionPanel.paintChildren(AbstractVisionPanel.java:279)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at com.inductiveautomation.vision.api.client.components.model.AbstractVisionPanel.paintChildren(AbstractVisionPanel.java:279)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at com.inductiveautomation.vision.api.client.components.model.AbstractVisionPanel.paintChildren(AbstractVisionPanel.java:279)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JLayeredPane.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JLayeredPane.paint(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent._paintImmediately(Unknown Source)
at javax.swing.JComponent.paintImmediately(Unknown Source)
at javax.swing.RepaintManager$4.run(Unknown Source)
at javax.swing.RepaintManager$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$1200(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Caused by: com.inductiveautomation.ignition.client.gateway_interface.GatewayException: Unable to locate function 'SQLTags.read'
at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.newGatewayException(GatewayInterface.java:341)
at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendMessage(GatewayInterface.java:315)
at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendMessage(GatewayInterface.java:268)
at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.invoke(GatewayInterface.java:894)
at com.inductiveautomation.ignition.client.sqltags.impl.db.DatasourceTagManager.read(DatasourceTagManager.java:434)
... 61 more
Exception in thread "AWT-EventQueue-2" java.lang.RuntimeException: com.inductiveautomation.ignition.client.gateway_interface.GatewayException: Unable to locate function 'SQLTags.read'
at com.inductiveautomation.ignition.client.sqltags.impl.db.DatasourceTagManager.read(DatasourceTagManager.java:436)
at com.inductiveautomation.ignition.client.sqltags.impl.ClientTagManagerImpl.read(ClientTagManagerImpl.java:192)
at com.inductiveautomation.ignition.examples.ce.components.StandardTank.drawTag(StandardTank.java:103)
at com.inductiveautomation.ignition.examples.ce.components.StandardTank.paintComponent(StandardTank.java:91)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at com.inductiveautomation.vision.api.client.components.model.AbstractVisionPanel.paintChildren(AbstractVisionPanel.java:279)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at com.inductiveautomation.vision.api.client.components.model.AbstractVisionPanel.paintChildren(AbstractVisionPanel.java:279)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at com.inductiveautomation.vision.api.client.components.model.AbstractVisionPanel.paintChildren(AbstractVisionPanel.java:279)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at com.inductiveautomation.vision.api.client.components.model.AbstractVisionPanel.paintChildren(AbstractVisionPanel.java:279)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at com.inductiveautomation.vision.api.client.components.model.AbstractVisionPanel.paintChildren(AbstractVisionPanel.java:279)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at com.inductiveautomation.vision.api.client.components.model.AbstractVisionPanel.paintChildren(AbstractVisionPanel.java:279)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent._paintImmediately(Unknown Source)
at javax.swing.JComponent.paintImmediately(Unknown Source)
at javax.swing.RepaintManager$4.run(Unknown Source)
at javax.swing.RepaintManager$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$1200(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Caused by: com.inductiveautomation.ignition.client.gateway_interface.GatewayException: Unable to locate function 'SQLTags.read'
at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.newGatewayException(GatewayInterface.java:341)
at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendMessage(GatewayInterface.java:315)
at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendMessage(GatewayInterface.java:268)
at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.invoke(GatewayInterface.java:894)
at com.inductiveautomation.ignition.client.sqltags.impl.db.DatasourceTagManager.read(DatasourceTagManager.java:434)
... 51 more
This is the whole trace. The offending line is a copy/paste of Colby’s code.
I found this thread: Client module with sql tag read?
And was able to get it to work by using
Tag tag = getAppContext().getTagManager().getTag(TagPathParser.parse("", tagPath));
So seems like it is a bug on Ignitions end that has been known about since Feb '17 but not fixed yet.
Oops, yep, doesn’t look like we ever fixed that.
Sounds like a bug that is extremely low priority because it can only be triggered by a module developer, and has a work-around.
Side note: you’re trying to do this inside of a paint() operation? That’s just crazy, as a a visual update should never have to wait for a gateway message/reply. Ideally, painting should never have to involve anything outside the component. You’re begging to have random freezes in your UI.
So low priority it seems we never made a ticket for it...
I just fixed it though... due in ??? for 7.9.??? 
No worries Kevin 
Thanks for replying.
Right, fully aware of this. Just getting my feet wet with the SDK and wanted to just read a single tag and display it.
Now that I got the tag read working, I have moved this functionality to a tag subscription that updates the value displayed in the component as the new tag value comes in.