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| jim777 |
 Posted: Mon Feb 13, 2012 11:50 am Post subject: Is it possible to create a shared array in esql? |
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Novice
Joined: 13 Feb 2012
Posts: 16
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Hi guys, is it possible to create a shared array in ESQL that can be accessed from mulitple flows within an execution group.
The documentation talks about a shared character data type and that works great but I'm trying to setup a shared array/list of strings to be used, is this possible?
I see examples of setting up the list but only on the output message, I want to set some variables to that other flows within the execution group can see. |
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| lancelotlinc |
| Posted: Mon Feb 13, 2012 11:52 am Post subject: |
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Jedi Knight
Joined: 22 Mar 2010
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Location: Bloomington, IL USA
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| adubya |
| Posted: Mon Feb 13, 2012 11:53 am Post subject: |
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Partisan
Joined: 25 Aug 2011
Posts: 377
Location: GU12, UK
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| The "widest" scope of an ESQL variable is at a flow level so multiple instances of a specific flow can share a variable but cross-flow sharing isn't supported natively in ESQL. |
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| Vitor |
| Posted: Mon Feb 13, 2012 11:56 am Post subject: Re: Is it possible to create a shared array in esql? |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| jim777 wrote: |
| The documentation talks about a shared character data type and that works great but I'm trying to setup a shared array/list of strings to be used, is this possible? |
I don't think the documentation talks about a shared character data type; IIRC it talks about a shared attribute of any data type. So if you were to identify a datatype capable of holding data in the form you describe, you could apply that attribute in the declare statement.
Given your comment that a shared character "works great", I would direct you to the scope of such a variable.
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| Vitor |
| Posted: Mon Feb 13, 2012 12:03 pm Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
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Location: Texas, USA
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| lancelotlinc wrote: |
| Yes: using a Singleton or a solidDB in-memory database. |
Note the OP specifically asked "in ESQL". Correct me if I'm wrong, but you'd need to drop into Java to create a Singleton.
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| lancelotlinc |
| Posted: Mon Feb 13, 2012 12:06 pm Post subject: |
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| Vitor |
| Posted: Mon Feb 13, 2012 12:07 pm Post subject: Re: Is it possible to create a shared array in esql? |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| jim777 wrote: |
| I want to set some variables to that other flows within the execution group can see. |
You might also consider the infamous IA91 support pac - The Cache Node.
It may or may not fit your requirements. But it's an option. Possibly better than going into native Java (AFAIK there's Java in there somewhere). I advise you to look at the discussions on IA91 on this forum before deciding; not all of them are flattering.
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| Vitor |
| Posted: Mon Feb 13, 2012 12:11 pm Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
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| lancelotlinc wrote: |
| You are correct, Sir Vitor, however, the Singleton can be accessed from ESQL. |
Interesting; my Java knowledge increases (which isn't that tricky). So 2 questions:
- how do you populate the Singleton in ESQL?
- how so you access it in ESQL?
Code snippits would be nice.
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| lancelotlinc |
| Posted: Mon Feb 13, 2012 12:27 pm Post subject: |
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Jedi Knight
Joined: 22 Mar 2010
Posts: 4941
Location: Bloomington, IL USA
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First, you create the Singleton code in a jar:
| Code: |
private static class SingletonHolder {
public static final SingletonMain INSTANCE = new SingletonMain();
}
public static SingletonMain getInstance() {
return SingletonHolder.INSTANCE;
}
public static void addAGlobalValue( string someValueToAdd ){ ... }
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Next, you access the Singleton from ESQL:
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CREATE PROCEDURE addAGlobalValue( IN report CHARACTER )
LANGUAGE JAVA
EXTERNAL NAME "com.<yourcompanyname>.middleware.common.util.SingletonMain.addAGlobalValue";
CALL addAGlobalValue( someData );
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| mgk |
| Posted: Mon Feb 13, 2012 12:33 pm Post subject: |
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Padawan
Joined: 31 Jul 2003
Posts: 1647
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| Quote: |
| Hi guys, is it possible to create a shared array in ESQL that can be accessed from mulitple flows within an execution group. |
Yes, the ESQL ROW datatype is actually a tree and a tree can contain repeating elements, like an array, so a SHARED ROW will do what you need here, all within ESQL 
Kind regards,
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| adubya |
| Posted: Mon Feb 13, 2012 12:36 pm Post subject: |
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Partisan
Joined: 25 Aug 2011
Posts: 377
Location: GU12, UK
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| mgk wrote: |
| Quote: |
| Hi guys, is it possible to create a shared array in ESQL that can be accessed from mulitple flows within an execution group. |
Yes, the ESQL ROW datatype is actually a tree and a tree can contain repeating elements, like an array, so a SHARED ROW will do what you need here, all within ESQL
Kind regards, |
Don't the scope rules stop the variable being shared between different flows though ? |
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| mgk |
| Posted: Mon Feb 13, 2012 12:40 pm Post subject: |
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Padawan
Joined: 31 Jul 2003
Posts: 1647
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| Quote: |
| Don't the scope rules stop the variable being shared between different flows though ? |
Yes 
I did not notice that part of your original post, sorry. Given that a Java or .NET singleton would be a good alternative...
Kind Regards,
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| Vitor |
| Posted: Mon Feb 13, 2012 12:50 pm Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| lancelotlinc wrote: |
First, you create the Singleton code in a jar:
| Code: |
private static class SingletonHolder {
public static final SingletonMain INSTANCE = new SingletonMain();
}
public static SingletonMain getInstance() {
return SingletonHolder.INSTANCE;
}
public static void addAGlobalValue( string someValueToAdd ){ ... }
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Next, you access the Singleton from ESQL:
| Code: |
CREATE PROCEDURE addAGlobalValue( IN report CHARACTER )
LANGUAGE JAVA
EXTERNAL NAME "com.<yourcompanyname>.middleware.common.util.SingletonMain.addAGlobalValue";
CALL addAGlobalValue( someData );
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So you don't create & access the Singleton from ESQL. You write some Java code, add that to a jar, load the jar into the broker and access the Java from ESQL.
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| lancelotlinc |
| Posted: Mon Feb 13, 2012 12:53 pm Post subject: |
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Joined: 22 Mar 2010
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| fjb_saper |
| Posted: Mon Feb 13, 2012 10:20 pm Post subject: |
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Grand High Poobah
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Posts: 20768
Location: LI,NY
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| lancelotlinc wrote: |
| Yes, I'm sorry if I were not clear before. |
And there I thought that a properly formed singleton had some "synchronized" methods... 
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