Using Caché Objects - InterSystems Documentation

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Using Callback Methods Since different types of classes support different events, not all callback methods are available to all classes. For example, callback methods triggered by saving or deleting an object cannot be accessed by registered objects since these objects cannot be saved or deleted. With the exception of %OnDetermineClass, these methods can be used to perform any processing desired at the relevant event. %OnDetermineClass is a special case. When %Open or %Delete is given a partially-formed OID, it calls the %OnDetermineClass method, if the user has provided one, to obtain the actual class name. If %OnDetermineClass indicates the object belongs to a different class, %Open or %Delete will dispatch to the new class' %Open or %Delete method. If there is no %OnDetermineClass method, %Open and %Delete simply assume the current class is the correct class. 20.1 %OnAddToSaveSet This instance method is called by the %AddToSaveSet method. The %AddToSaveSet method itself is called on an object whose %Save method has been invoked, as well as all other objects referenced by that object that have been loaded into memory. %AddToSaveSet can also be invoked directly from %OnAddToSaveSet. If %OnAddToSaveSet modifies another object, then it is the responsibility of %OnAddToSaveSet to invoke %AddToSaveSet on that modified object. When you invoke %Save on an object, called, for example, MyPerson, Caché generates a list of objects that MyPerson references. A SaveSet is the list of objects consisting of the object to be saved and all the objects that it references. In the example, the SaveSet might include referenced objects MySpouse, MyDoctor, and so on. The syntax of %OnAddToSaveSet is: ReturnValue %OnAddToSaveSet(SaveDepth As %Integer, Insert As %Integer, CallCount As %Integer) where: 170 Using Caché Objects
%OnAfterSave ReturnValue SaveDepth Insert CallCount A %Status code, where an error code causes the save to fail and the transaction to be rolled back. An integer value passed in from %AddToSaveSet that represents the internal state of SaveSet construction. If you use %OnAddToSaveSet to add any other records to the SaveSet, pass this value to %AddToSaveSet without change. A flag indicating if the object being saved is being inserted into the extent (1) or that it is already part of the extent (0). The number of times that %OnAddToSaveSet has been called for this object. Due to the networked nature of object references it is possible that %AddToSaveSet can be invoked on the same object multiple times. You can update objects, create new objects, delete objects and ask objects to include themselves in the current SaveSet by calling %AddToSaveSet. If you modify the current instance or any of its descendants, you must let the system know that you have done this by calling %AddToSaveSet for the modified instance(s) and passing a value of 1 for the method's Refresh argument. None of the modification restrictions imposed on %OnAfterSave, %OnBeforeSave, or %OnValidateObject are in place for %OnAddToSaveSet. If you delete an object using %OnAddToSaveSet, you need to call %RemoveFromSaveSet to clean up any dangling references to it. This method is available to the %Library.RegisteredObject class and its subclasses. 20.2 %OnAfterSave This instance method is called by the %Save method just after an object is saved. This method allows you to perform actions outside the scope of the object being saved, such as queueing a later notification action; an example of this is a bank using the deposit in excess of a certain amount to cause it to send the customer an explanation of its deposit policies. Its syntax is: ReturnValue %OnAfterSave(Insert as Boolean) where: Using Caché Objects 171
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Using Caché Objects Version 5.2 01
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Table of Contents 1 Introduction to
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7 Properties ......................
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13.1 Inheritance and SQL ..........
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20.8 %OnNew .......................
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List of Figures Embeddable Objects
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1 Introduction to Caché Objects Th
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1.2 Class Definitions and the Class
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Development Tools Caché Class Libr
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• The Caché EJB Binding—a vers
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2 Object-Oriented Database Developm
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Encapsulation Caché exploits inher
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3 The Caché Object Model The Cach
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Referring to an Object — OREF, OI
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Types of Classes 3.2.1 Transient Ob
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Types of Classes Embeddable Objects
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A class inherits all of the specifi
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2. It resolves inheritance—it det
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Caché Classes • Class Parameters
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Caché Classes ClientDataType Descr
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Caché Classes Internally, this wor
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Packages Class Packages Any of thes
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Packages Letting the compiler resol
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Packages • “%Library” —any
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Methods where count and state are d
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Methods 6.4 Method Language You hav
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Methods 6.6 Instance and Class Meth
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Methods Write dog.Speak() Which cou
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Properties 7.1 Property Keywords Yo
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Properties Property Behavior The pr
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Properties 7.5 Attribute Properties
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Properties You can manipulate a col
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8 Class Queries Class queries provi
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Query Basics Final Specifies that s
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Caché ObjectScript. These queries
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The data in Row is the result of ex
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9 Indices Indexes provide a mechani
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Index Collation 9.2 Index Collation
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10 Using Objects with Caché Object
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Executing Methods 10.1.3 Executing
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Opening Objects 10.3 Opening Object
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where oref is the OREF of the speci
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For example, to populate the Home p
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change the second vaccination recor
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There are two types of array proper
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Saving Objects 10.5 Saving Objects
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mation. Again, this method deletes
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Set rset = ##class(%ResultSet).%New
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Executing Queries // Create a Resul
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Data Types 11.1 Available Types Cac
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Data Types • INDEXSUBSCRIPTS —
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Data Types CLIENTDATATYPE Values Va
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Data Types SQLCATEGORY Values Value
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Data Types The property is restrict
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Object Persistence 1. Its primary (
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Object Persistence Note: In a multi
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Object Persistence // Open person "
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Object Persistence For example: //
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Object Persistence If a persistent
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Object Persistence The storage clas
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13 Objects and SQL A key aspect of
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The Object-SQL Projection 13.2 The
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The Object-SQL Projection 13.2.2.1
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Page 133 and 134: If the list for a particular instan
Page 135 and 136: Triggers are, however, fired by the
Page 137 and 138: 14 Relationships A relationship is
Page 139 and 140: Relationship Basics the relationshi
Page 141 and 142: An Invoice class class MyApp.Invoic
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Page 146 and 147: Streams Stream data may be stored i
Page 148 and 149: Streams 15.2.2 Copying Data between
Page 150 and 151: Streams Set stream=##class(%Stream.
Page 153 and 154: 16 Class Projections Class projecti
Page 155 and 156: RemoveProjection The RemoveProjecti
Page 157 and 158: 17 Object Synchronization Object sy
Page 159 and 160: About Updates • If two changes re
Page 161 and 162: About Updates Two Synchronized Data
Page 163 and 164: • classname is a quoted string th
Page 165 and 166: Set Status = TargetSyncSet.Import(f
Page 167 and 168: 18 Method Generators A powerful fea
Page 169 and 170: Method Generator Context 6. It copi
Page 171: Implementing Method Generators 3. A
Page 174 and 175: The Caché Data Population Utility
Page 184 and 185: Using Callback Methods ReturnValue
Page 186 and 187: Using Callback Methods 20.6 %OnDele
Page 188 and 189: Using Callback Methods 20.10 %OnRol
Page 191 and 192: 21 Object-Specific ObjectScript Fea
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Page 195 and 196: ##super Syntax 21.4 ##super Syntax
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Page 200 and 201: Dynamic Dispatch 22.2 Content of Me
Page 202 and 203: Dynamic Dispatch %DispatchMethod ca
Page 205 and 206: 23 Class Definition Classes The Cac
Page 207: You can get detailed information ab
Page 210 and 211: Internet Classes addressed to , its
Page 212 and 213: Internet Classes For more informati
Page 214 and 215: Object Concurrency Setting 1 2 3 4
Page 216 and 217: Object Concurrency Note: You can us
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Using Caché Objects - InterSystems Documentation

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