Using TCP Adapters with Ensemble - InterSystems Documentation

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Creating Custom TCP Adapter Classes• An outbound adapter class define methods that create a TCP connection, read or write over the connection, anddisconnect.To define these methods, use helper methods inherited by your class.4. Compile the class, which also saves it.8.2 Common Customizations in TCP Adapter SubclassesThe following list suggests some common customizations in TCP adapter subclasses, in addition to implementing themethods that the adapter needs:• The Terminators property is a common property to edit. You can specify an initial expression for this property.Your adapter class can set a value for Terminators using the ObjectScript function $CHAR or $C to identify the ASCIIvalue for the character. The following example from EnsLib.TCP.TextLineInboundAdapter sets Terminators to thenewline character (ASCII 10):Property Terminators As %String [ InitialExpression = {$C(10)} ];For more information about functions like $CHAR, see “Caché ObjectScript Functions” in the Caché ObjectScriptReference.You can set Terminators to a single character or to a multi-character string. If you supply a string for the Terminatorsvalue, Ensemble uses the string as follows:– Any one of the characters in the string serves to terminate the input.– The complete string of characters is appended to the output.• You can expose additional properties for runtime configuration by providing a SETTINGS parameter whose value isa comma-separated list of the properties that you want to expose. For example:/// The full pathname for a transaction log file on the local computerProperty LogPath As %String(MAXLEN = 200) [ Required ];/// The simple file name for the logProperty LogSpec As %String(MAXLEN = 60) [ InitialExpression = "*" ];/// These properties are exposed for runtime configuration via the portalParameter SETTINGS = "LogPath,LogSpec";At runtime, properties from this SETTINGS list appear in the display on the [Ensemble] > [Production Configuration]page as additional settings.• If you need to require login credentials for the connection, simply add the property name Credentials to theSETTINGS list. The Credentials property is already defined as a %String in the base class Ens.Adapter.For background information, see “Username and Password Credentials” in the chapter “Production Concepts” inDeveloping Ensemble Productions.• (For inbound adapters) You can also enforce a pool size of 1 by setting the parameter SINGLEPOOLJOB = 1:/// Force a single listener job regardless of PoolSize settingParameter SINGLEPOOLJOB = 1;Any subclass of this adapter class or a business service class that uses such an adapter class can use this parameter inits class code to better control the pool size.52 Using TCP Adapters with Ensemble
Customizing Callbacks of Inbound TCP Adapters8.3 Customizing Callbacks of Inbound TCP AdaptersIf you subclass or copy an inbound TCP adapter, you can override these methods with unique behaviors:OnConnected()OnInit()Method OnConnected() As %StatusWhenever a connection exists to the configured TCP client, the adapter calls OnConnected() to read a streamfrom the TCP data source. This read operation is controlled by adapter settings.OnConnected() uses helper methods to parse the data.Upon successfully reading data, OnConnected() calls the Ensemble framework’s ProcessInput() method to passthe received data stream to the associated business service. If this call returns an outbound stream, OnConnected()writes that data as a reply to the TCP client.If no data is available to read from the TCP connection during the CallInterval time, OnConnected() returnswithout doing anything.Also see the OnTask() method.Method OnInit() As %StatusThe Ensemble framework calls OnInit() after creating the inbound adapter instance and setting its configurableproperty values. The OnInit() method provides a way for the inbound adapter to perform any special setup actions.Depending on the values of the relevant adapter settings, one of these actions might be to initiate a connectionbetween the adapter and the TCP client it will listen to, or to construct any object properties that the adapter willuse.OnTearDown()OnTask()Method OnTearDown() As %StatusThe Ensemble framework calls OnTearDown() during shutdown, before destroying the inbound adapter object.The OnTearDown() method provides a way for an inbound adapter to perform any special cleanup actions suchas disconnecting from the TCP client.Method OnTask() As %StatusAll inbound adapters have an OnTask() method, where the bulk of the adapter work is done. Once a productionstarts, each business service calls the OnTask() method of its associated inbound adapter class, at the time intervaldetermined by the adapter’s CallInterval setting. For details, see “Business Service Life Cycle” in the “BusinessServices” in Developing Ensemble Productions.For more detailed information about adapter class internals, open the class in Studio or use the InterSystems Class Reference.8.4 Customizing Callbacks of Outbound TCP AdaptersIf you subclass or copy an outbound TCP adapter, you can override these methods with unique behaviors:Using TCP Adapters with Ensemble 53
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Using TCP Adapters with EnsembleEns
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List of TablesTable 6-1: TCP Status
Page 9 and 10: 1Choosing a TCP AdapterThis chapter
Page 11 and 12: 2Using the TCP Counted Inbound Adap
Page 13 and 14: Using the AdapterAn Ensemble produc
Page 15 and 16: Sample Business Service Class Code4
Page 17: Adapter SettingsEndianA choice of B
Page 20 and 21: Using the TCP Counted Outbound Adap
Page 28 and 29: Using the TCP Counted XML Inbound A
Page 34 and 35: Using the TCP Counted XML Outbound
Page 42 and 43: Using the TCP Text Line Inbound Ada
Page 50 and 51: Using the TCP Text Line Outbound Ad
Page 60 and 61: Creating Custom TCP Adapter Classes
Page 62 and 63: Settings for the Abstract TCP Adapt
Page 65 and 66: BCommon Tasks in the Management Por
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