Programming Guide - Actian

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How You Can Write an AssistantNote: Fields generated from a field template are completely overwritten whenthe ApplyTemplate utility is run; therefore, any changes made to the field arelost.Be aware that any changes you make to your frame or field must be made insuch a way that they are not overwritten by the ApplyTemplate utility.OpenROAD provides a mechanism whereby you can identify the areas of theframe that are designated as “user” areas—where user modifications arepreserved. The other areas belong to and are completely overwritten by theApplyTemplate utility. This involves several considerations when writing andmodifying your assistant procedure code. These concepts are discussed in thefollowing sections of this chapter.How You Can Write an AssistantIn OpenROAD, the developer can associate a 4GL procedure with a frame orfield template, which is then referred to as the template's “assistant.” Thistemplate, when combined with an assistant procedure, enables the user tocreate frames and fields that are more powerful and immediately useful thanthose created from templates alone.The following specifications for developing an assistant procedure include:• The assistant must be a 4GL procedure. The 4GL procedure itself can,however, subsequently call frames to interact with users.• The 4GL procedure has three parameters, all of which are mandatory.For frame template assistant procedures, the parameters are:fsParameter Type: FrameSourceSpecifies the instance of the frame that is currently being created ormodified by the ApplyTemplate utilityreturn_codeParameter Type: Integer (ER_OK, ER_FAIL)Specifies the return code. It is assigned the value ER_OK if the procedurecompletes successfully; otherwise, it is assigned ER_FAIL.420 <strong>Programming</strong> <strong>Guide</strong>
How You Can Write an Assistantbatch_modeParameter Type: Integer (TRUE, FALSE)Specifies a Boolean parameter telling the frame assistant procedurewhether it is being run in batch mode. If TRUE, the procedure cannotdepend on any form of user interaction, including calling user frames foruser input. If FALSE, the frame assistant can make use of frames for userinput.In the ApplyTemplate utility dialog, selecting the Batch option passes avalue of TRUE; and for the Interactive option, FALSE.For field template assistant procedures, the parameters are:ffParameter Type: FormFieldSpecifies the instance of the field that is currently being createdreturn_codeParameter Type: Integer (ER_OK, ER_FAIL)Specifies a return code. It is assigned the value ER_OK if the procedurehas completed successfully; otherwise, it is assigned ER_FAIL.batch_modeParameter Type: Integer (TRUE, FALSE)Specifies a Boolean parameter telling the field assistant procedure whetherit is being run in batch mode. If TRUE, the procedure cannot depend onany form of user interaction, including calling user frames for user input. IfFALSE, the field assistant can make use of frames for user input.In the ApplyTemplate utility, selecting the Batch option passes a value ofTRUE; and for the Interactive option, FALSE.The following sections present examples of frame and field templateassistants.Example—Frame Template AssistantIn this example, a frame template assistant procedure has been designed tocustomize a frame template. The frame template assistant procedure promptsthe user for a text string, assigns that string to a dynamically created FreeTrimfield, and then places the field on the form.Writing a Template Assistant 421
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Ingres OpenROAD ® 2006Programming
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ContentsChapter 1: Introduction 13I
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Using an Object-oriented Approach t
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How You Can Retrieve Array Informat
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Chapter 12: Managing Event Queues 3
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Chapter 17: Preprocessing Your 4GL
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Chapter 1: IntroductionThis section
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ConventionsConventionsThe following
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Your Support OptionsYour Support Op
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OpenROAD NamesThe rules for these n
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OpenROAD Names3. Enclosing field sc
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OpenROAD NamesThe following code ex
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VariablesThe following illustrates
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VariablesIn the first example, film
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VariablesOpenROAD checks references
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VariablesHow You Can Declare Dynami
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VariablesFor example, assume that y
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ExpressionsHowever, you cannot use
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ExpressionsThe general syntax for h
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ExpressionsCurSessionSpecifies, for
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ExpressionsString OperatorThe conca
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ExpressionsOperatorlikenot likeOper
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Expressions• You can use the esca
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ExpressionsBecause procedures can r
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System-defined FunctionsThis rule h
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System-defined FunctionsNameOperand
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System-defined FunctionsName Operan
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System-defined FunctionsNameshift(c
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System-defined FunctionsSome date f
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System-defined FunctionsThe followi
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System-defined FunctionsCount Funct
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System-defined FunctionsResult Data
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Chapter 3: Writing Scripts and Proc
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ScriptsDeclare local variables that
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ScriptsUserEventSpecifies a user ev
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ScriptsExample—Field and Menu Ite
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ProceduresOpenROAD lets you create
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ProceduresReturning from a Procedur
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ProceduresExample—Local Procedure
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Procedures4GL DataTypedatemoneyfloa
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Calling Procedures• In this call
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Calling ProceduresparameterAssigns
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How Procedure Handles Work (ProcHan
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Compiler LimitationsYou can avoid t
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How You Can Invoke FramesHow the Cu
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How You Can Invoke FramesHow You Ca
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How You Can Invoke FramesFor more i
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How You Can Invoke FramesFor exampl
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How You Can Invoke FramesIf the obj
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How You Can Invoke FramesHow You Ca
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How You Can Invoke Frames• Prompt
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How You Can Invoke FramesThe syntax
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How You Can Run Non-interactive App
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How You Can Reference ObjectsHow Yo
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How You Can Reference ObjectsHow Yo
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How You Can Reference ObjectsUse an
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Using an Object-oriented Approach t
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InheritanceClass RelationshipsYou c
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InheritanceYou can specify a user c
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InheritanceThe Terminate method is
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How You Can Create a User ClassWhen
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How You Can Create a User ClassHow
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How You Can Create a User Class3. G
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How You Can Create a User ClassTo e
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External ClassesHow You Can Use Ext
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External ClassesExample—ActiveX C
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How You Can Manipulate Objects Gene
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Overview of the OpenROAD System Cla
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How You Can Access a Database with
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How You Can Manage TransactionsHow
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How You Can Manage TransactionsDivi
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How You Can Manage TransactionsTo c
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How Programming for Multiple Sessio
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Handling Database ErrorsIn OpenROAD
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Handling Database ErrorsIf a databa
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Handling Database ErrorsFor example
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Handling Database Errorsbeginerr_no
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Arrays and Table Fields—Conceptua
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ArraysBecause an individual attribu
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ArraysDeclaring an array variable d
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ArraysThe following statement puts
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Arraysfor i = custtable.FirstRow to
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ArraysHow You Can Add Rows to an Ar
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ArraysThe inserted row is blank bec
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ArraysThe following code fragment i
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ArraysThese attributes are:AllRowsR
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ArraysAttributes used in a sort can
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ArraysThe format parameter can be a
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Table FieldsTable Fields and Associ
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Table FieldsThe following applicati
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Table FieldsThis syntax references
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Table FieldsFor example, the follow
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Table Field OperationsTable Field C
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Table Field OperationsHow You Can U
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Table Field OperationsWhen you use
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Table Field OperationsBiases can be
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Table Field OperationsThe following
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Table Field OperationsHow You Can T
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Table Field OperationsTableField Me
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Table Field OperationsFor example,
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Table Field OperationsControlling M
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CollectionsCollectionsA collection
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Collections// Open a workbook and p
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Listview_Treeview_DemoImport the De
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Listview FieldsListview FieldsA lis
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Listview FieldsextensionSpecifies a
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Listview FieldsImageIndexSpecifies
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TreeNode and Tree ClassesHeaderClic
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TreeNode and Tree ClassesMaintenanc
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Treeview FieldsHow You Can Build a
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Treeview FieldsThe second window is
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Treeview FieldsThe tree_ex2_class h
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Chapter 9: Working with Images and
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How You Can Work with ImagesThe fol
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How You Can Work with ImagesThe Col
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How You Can Work with ImagesThe Bit
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How You Can Work with Images5. Add
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How You Can Work with Text StringsD
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How You Can Work with Text StringsH
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How You Can Call 3GL ProceduresIn t
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How You Can Use Exec 4GL Statements
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How You Can Link 3GL ProceduresHow
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Sample 3GL ProceduresExec 4GL and E
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How You Can Use Data Entry Error Ha
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Chapter 12: Managing Event QueuesTh
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Event-based ProgrammingThe followin
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Event-based ProgrammingEvent TypesT
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Event-based ProgrammingField Events
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Event-based ProgrammingBecause all
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Event-based ProgrammingThe followin
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Event-based ProgrammingThe resume s
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Event-based ProgrammingNote: The da
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Communicating Between OpenROAD Fram
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How You Can Communicate with an Ext
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How You Can Communicate Between Ope
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How You Can Communicate Between Ope
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Chapter 14: Creating Dynamic Frames
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How You Can Change Field and Frame
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How You Can Change Field and Frame
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How Debugging an Application WorksW
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How Debugging an Application WorksH
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How Debugging an Application WorksW
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How Debugging an Application WorksS
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How Debugging an Application WorksL
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How Debugging an Application WorksA
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Appendix A: SQL Syntax SummaryThis
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SQL Syntax Summarygrant all [privil
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OpenSQL Syntax SummaryOpenSQL Synta
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Operating System CommandsThe follow
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BitmapObject classThe BitmapObject
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external classAn external class def
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local variableLocal variables conta
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StringObject classThe StringObject
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Index'' ' (single quotation marks)c
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Attributesdefined • 28referencing
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using to copy data • 244using wit
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application threads • 444array di
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examining values • 473hexadecimal
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Gmoney • 51numeric list • 53pad
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Namesapplication • 21dynamic •
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ReadOps attributesettings • 243Re
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concat function • 54functions •
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event chains • 323event queue •
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