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1 "{ Package: 'stx:libbasic' }" |
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2 |
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3 Object subclass:#SystemChangeNotifier |
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4 instanceVariableNames:'silenceLevel' |
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5 classVariableNames:'UniqueInstance' |
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6 poolDictionaries:'' |
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7 category:'Kernel-Classes' |
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8 ! |
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9 |
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10 !SystemChangeNotifier class methodsFor:'documentation'! |
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11 |
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12 documentation |
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13 " |
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14 For now, this implementation is mostly for squeak compatibility. |
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15 However, over time, we will move the change notification code from ClassDescription to here, |
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16 to make things easier to understand, and classDescription a little bit more lightweight. |
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17 " |
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18 ! ! |
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19 |
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20 !SystemChangeNotifier class methodsFor:'instance creaton'! |
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21 |
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22 uniqueInstance |
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23 "I am a singleton" |
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24 |
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25 UniqueInstance isNil ifTrue: [UniqueInstance := self basicNew initialize]. |
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26 ^ UniqueInstance |
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27 |
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28 " |
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29 UniqueInstance releaseAll. |
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30 UniqueInstance := nil |
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31 " |
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32 ! ! |
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33 |
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34 !SystemChangeNotifier methodsFor:'initialization'! |
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35 |
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36 initialize |
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37 "/ eventSource := SystemEventManager new. |
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38 silenceLevel := 0. |
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39 ! ! |
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40 |
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41 !SystemChangeNotifier methodsFor:'public'! |
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42 |
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43 doSilently: aBlock |
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44 "Perform the block, and ensure that no system notification are broadcasted while doing so." |
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45 |
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46 |result| |
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47 |
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48 silenceLevel := silenceLevel + 1. |
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49 [ |
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50 "/ temporary hack: |
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51 Class withoutUpdatingChangesDo:[ |
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52 result := aBlock value |
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53 ] |
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54 ] ensure: [ |
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55 silenceLevel > 0 ifTrue: [ |
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56 silenceLevel := silenceLevel - 1 |
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57 ] |
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58 ]. |
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59 ^ result. |
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60 ! |
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61 |
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62 isBroadcasting |
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63 ^ silenceLevel = 0 |
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64 ! ! |
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65 |
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66 !SystemChangeNotifier class methodsFor:'documentation'! |
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67 |
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68 version_CVS |
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69 ^ '$Header: /cvs/stx/stx/libbasic/SystemChangeNotifier.st,v 1.1 2009-10-12 19:11:38 cg Exp $' |
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70 ! ! |