Anonymous user
Singleton: Difference between revisions
→{{header|Caché ObjectScript}}
(added Caché ObjectScript) |
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Line 304:
///
/// <EXAMPLE>
/// Set one=##class(Singleton).Get(,.sc)
/// Set one.GlobalProperty="Some Value"
/// Set sc=one.Set()
/// </EXAMPLE>
///
▲/// global singleton object loaded. This class can also be extended.
Class User.Singleton Extends %SerialObject
{
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Property GlobalProperty As %String;
/// Refer to <LINK href=/AboutConcurrency.html>About Concurrency</LINK> for more details
ClassMethod Get(Output pStatus As %Status) As Singleton▼
/// on the optional <var>pConcurrency</var> argument.
▲ClassMethod Get(pConcurrency As %Integer = -1, Output pStatus As %Status = {$$$OK}) As Singleton
{
// check if singleton object already instantiated
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If oRef.%ClassName(1) = ..%ClassName(1) Quit
}
If $IsObject(oRef)
//
If '$IsValidNum(pConcurrency, 0, -1, 4) {
Lock +^CacheTempUser("Singleton", ..%ClassName(1))#"S":1▼
Set pStatus = $$$ERROR($$$LockTypeInvalid, pConcurrency)
If '$Test {▼
}▼
If pConcurrency = -1 Set pConcurrency=$xecute("Quit "_..#DEFAULTCONCURRENCY)
Set lockTO = $ZUtil(115,4), lockOK = 1
If (pConcurrency = 1) || (pConcurrency = 2) || (pConcurrency = 3) {
Lock +^CacheTempUser("Singleton", ..%ClassName(1))#"S":lockTO
Set lockOK = $Test
} ElseIf pConcurrency = 4 {
Set lockOK = $Test
}
If pConcurrency=4 {
Set pStatus = $$$ERROR($$$LockFailedToAcquireExclusive, ..%ClassName(1))
} Else {
Set pStatus = $$$ERROR($$$LockFailedToAcquireRead, ..%ClassName(1))
}
Quit $$$NULLOREF
}
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Set oRef = ..%Open(oId,, .pStatus)
// release
If (pConcurrency = 1) || (pConcurrency = 2) {
If $$$ISERR(pStatus) {▼
Lock -^CacheTempUser("Singleton", ..%ClassName(1))#"S"
}
// singleton object failed to load
▲ If $$$ISERR(pStatus) {
// release retained lock
If pConcurrency = 3 {
}
If pConcurrency = 4 {
}
Quit $$$NULLOREF
}
// store concurrency state and return in-memory object
Set oRef.Concurrency = pConcurrency
Quit oRef
}
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// obtain exclusive lock on global singleton object
If ..Concurrency '= 0 {
▲ Lock +^CacheTempUser("Singleton", ..%ClassName(1)):1
Set lockTO = $ZUtil(115,4)
If '$Test Quit $$$ERROR($$$LockFailedToAcquireExclusive, ..%ClassName(1))
}
// update global singleton object and release lock
Set ^CacheTempUser("Singleton", ..%ClassName(1)) = oId
If ..Concurrency '= 0 {
▲ Lock -^CacheTempUser("Singleton", ..%ClassName(1))
Lock -^CacheTempUser("Singleton", ..%ClassName(1))
▲ Quit $$$OK
}
Method %OnClose() As %Status [ Internal ]▼
{▼
// reference count for singleton object is now zero, so▼
▲ // release shared lock on global singleton object
▲ Lock -^CacheTempUser("Singleton", ..%ClassName(1))#"S"
Quit $$$OK
}
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Quit $$$ERROR($$$GeneralError, "Can't clone instance.")
}
▲Method %OnClose() As %Status [ Internal ]
▲{
▲ // reference count for singleton object is now zero, so
// release lock on global singleton object, if applicable
If ..Concurrency = 3 Lock -^CacheTempUser("Singleton", ..%ClassName(1))#"S"
If ..Concurrency = 4 Lock -^CacheTempUser("Singleton", ..%ClassName(1))
Quit $$$OK
}
Property Concurrency As %Integer [ Private, Transient ];
}
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