"{ Package: 'stx:libbasic2' }"

!

!Object methodsFor:'dependents-interests'!

addInterest:anInterest

    "install an interest forwarder.

     Here, we use the nonWeakDependencies."

    self addNonWeakDependent:anInterest

    "Created: 14.10.1996 / 22:27:34 / stefan"

! !

!Object methodsFor:'dependents-interests'!

expressInterestIn:aspect for:anObject sendBack:aSelector

    "arrange for aSelector to be sent to anObject whenever the receiver

     changes aspect."

    "/ for now, use an interestConverter, which is somewhat less efficient.

    "/ In the future, a more intelligent DependencyCollection class is planned for

    self addInterest:(InterestConverter 

                            destination:anObject 

                            selector:aSelector 

                            aspect:aspect)

    "

     |p b|

     b := [Transcript showCR:' -> the point changed'].

     p := Point new.

     Transcript showCR:'interest in #foo:'.

     p expressInterestIn:#foo for:b sendBack:#value.

     p x:1.

     Transcript showCR:'now changing #bar ... (expect no notification)'.

     p changed:#bar.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'now changing #foo ... (expect notification)'.

     p changed:#foo.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'no more interest in #foo:'.

     p retractInterestIn:#foo for:b.

     Transcript showCR:'now changing #foo ... (expect no notification)'.

     p changed:#foo.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'interest in #bar now:'.

     p expressInterestIn:#bar for:b sendBack:#value.

     Transcript showCR:'now changing #foo ... (expect no notification)'.

     p changed:#foo.

     Transcript showCR:'now changing #bar ... (expect notification)'.

     p changed:#bar.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'interest in #foo now:'.

     p expressInterestIn:#foo for:b sendBack:#value.

     Transcript showCR:'now changing #foo ... (expect notification)'.

     p changed:#foo.

     Transcript showCR:'now changing #bar ... (expect notification)'.

     p changed:#bar.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'no more interests:'.

     p retractInterestsFor:b.

     Transcript showCR:'now changing #foo ... (expect no notification)'.

     p changed:#foo.

     Transcript showCR:'now changing #bar...  (expect no notification)'.

     p changed:#bar.

     Transcript cr.

     p release.

    "

    "Created: 19.4.1996 / 10:26:22 / cg"

    "Modified: 19.4.1996 / 12:34:08 / cg"

    "Modified: 14.10.1996 / 22:28:20 / stefan"

! !

!Object methodsFor:'dependents-interests'!

interests

    "return a Collection of interests - empty if there is none.

     Here, we use the nonWeakDependents for interests."

    ^ self nonWeakDependents

    "Created: / 14.10.1996 / 22:20:51 / stefan"

    "Modified: / 30.1.1998 / 14:07:35 / cg"

! !

!Object methodsFor:'dependents-interests'!

interestsFor:someOne

    "return a collection of interests of someOne - empty if there is none."

    |coll deps|

    deps := self interests.

    deps size == 0 ifTrue:[^ #()].

    coll := IdentitySet new.

    deps do:[:dep |

        (dep isInterestConverter) ifTrue:[

            dep destination == someOne ifTrue:[

                coll add:dep.

            ]

        ]

    ].

    ^ coll

    "Created: / 30.1.1998 / 14:02:26 / cg"

    "Modified: / 30.1.1998 / 14:08:24 / cg"

! !

!Object methodsFor:'dependents-interests'!

onChangeEvaluate:aBlock

    "arrange for aBlock to be evaluated whenever the receiver changes."

    ^ self onChangeSend:#value to:aBlock

    "

     |p b|

     b := [Transcript showCR:' -> the point changed'].

     p := Point new.

     Transcript showCR:'interest in #foo:'.

     p onChangeEvaluate:b.

     p x:1.

     Transcript showCR:'now changing #bar ... (expect no notification)'.

     p changed:#bar.

     p retractInterests.

     p changed:#bar.

    "

! !

!Object methodsFor:'dependents-interests'!

onChangeSend:aSelector to:anObject

    "arrange for aSelector to be sent to anObject whenever the receiver

     changes."

    "/ for now, use an interestConverter, which is somewhat less efficient.

    "/ In the future, a more intelligent DependencyCollection class is planned for

    ((self interests ? #())

        contains:[:anInterest |

            (anInterest isInterestConverter)

            and:[ anInterest destination == anObject

            and:[ anInterest selector == aSelector]]

        ])

            ifTrue:[^ self].

    self addInterest:(InterestConverter 

                          destination:anObject 

                          selector:aSelector)

    "

     |p b|

     b := [Transcript showCR:'the point changed'].

     p := Point new.

     p onChangeSend:#value to:b.

     p x:1.

     Transcript showCR:'now changing'.

     p changed.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'now changing'.

     p changed.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'no more interest'.

     p retractInterestsFor:b.

     Transcript showCR:'now changing again'.

     p changed.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'interest again'.

     p onChangeSend:#value to:b.

     Transcript showCR:'now changing again'.

     p changed.

     Transcript cr.

    "

    "Created: 19.4.1996 / 10:26:38 / cg"

    "Modified: 19.4.1996 / 12:34:26 / cg"

    "Modified: 14.10.1996 / 22:28:27 / stefan"

! !

!Object methodsFor:'dependents-interests'!

removeInterest:anInterest

    "remove an interest forwarder.

     Here, we use the nonWeakDependencies."

    self removeNonWeakDependent:anInterest

    "Created: 14.10.1996 / 22:21:59 / stefan"

! !

!Object methodsFor:'dependents-interests'!

retractInterestIn:aspect for:someOne

    "remove the interest of someOne in the receiver changing aspect

     (as installed with #expressInterestIn:for:sendBack:)."

    "/ for now, remove the interestConverter.

    "/ In the future, a more intelligent DependencyCollection class is planned for

    self retractInterestsForWhich:[:i | (i aspect == aspect) and:[i destination == someOne]]

    "

     |p b|

     b := [Transcript showCR:'the point changed'].

     p := Point new.

     Transcript showCR:'interest in #foo'.

     p expressInterestIn:#foo for:b sendBack:#value.

     p x:1.

     Transcript showCR:'now changing #bar'.

     p changed:#bar.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'now changing #foo'.

     p changed:#foo.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'no more interest in #foo'.

     p retractInterestIn:#foo for:b.

     Transcript showCR:'now changing #foo'.

     p changed:#foo.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'interest in #bar now'.

     p expressInterestIn:#bar for:b sendBack:#value.

     Transcript showCR:'now changing #foo'.

     p changed:#foo.

     Transcript showCR:'now changing #bar'.

     p changed:#bar.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'interest in #foo now'.

     p expressInterestIn:#foo for:b sendBack:#value.

     Transcript showCR:'now changing #foo'.

     p changed:#foo.

     Transcript showCR:'now changing #bar'.

     p changed:#bar.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'no more interests'.

     p retractInterestsFor:b.

     Transcript showCR:'now changing #foo'.

     p changed:#foo.

     Transcript showCR:'now changing #bar'.

     p changed:#bar.

     Transcript cr.

    "

    "Created: / 19.4.1996 / 10:27:11 / cg"

    "Modified: / 14.10.1996 / 22:21:19 / stefan"

    "Modified: / 30.1.1998 / 14:05:34 / cg"

! !

!Object methodsFor:'dependents-interests'!

retractInterests

    "remove all interests in the receiver changing aspect

     (as installed with #expressInterestIn:for:sendBack:)."

    "/ for now, remove the interestConverter.

    "/ In the future, a more intelligent DependencyCollection class is planned for

    self retractInterestsForWhich:[:i | true ]

! !

!Object methodsFor:'dependents-interests'!

retractInterestsFor:someOne

    "remove the interest of someOne in the receiver 

     (as installed with #onChangeSend:to:)."

    "/ for now, remove the interestConverter.

    "/ In the future, a more intelligent DependencyCollection class is planned for

    self retractInterestsForWhich:[:i | i destination == someOne ]

    "

     |p b|

     b := [Transcript showCR:'the point changed'].

     p := Point new.

     p onChangeSend:#value to:b.

     p x:1.

     Transcript showCR:'now changing'.

     p changed.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'now changing'.

     p changed.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'no more interest'.

     p retractInterestsFor:b.

     Transcript showCR:'now changing again'.

     p changed.

     Transcript cr.

     Delay waitForSeconds:1.

     Transcript showCR:'interest again'.

     p onChangeSend:#value to:b.

     Transcript showCR:'now changing again'.

     p changed.

     Transcript cr.

    "

    "Created: / 19.4.1996 / 10:23:46 / cg"

    "Modified: / 14.10.1996 / 22:21:25 / stefan"

    "Modified: / 30.1.1998 / 14:04:52 / cg"

! !

!Object methodsFor:'dependents-interests'!

retractInterestsForWhich:aBlock

    "remove all interests in the receiver changing aspect

     (as installed with #expressInterestIn:for:sendBack:)."

    "/ for now, remove the interestConverter.

    "/ In the future, a more intelligent DependencyCollection class is planned for

    |deps coll|

    deps := self interests.

    deps size ~~ 0 ifTrue:[

        "/ cannot removeDependent within the loop - the interests collection rehashes

        coll := OrderedCollection new.

        deps do:[:dep |

            dep isInterestConverter ifTrue:[

                (aBlock value:dep) ifTrue:[coll add:dep].

            ]

        ].

        coll do:[:dep |

            self removeInterest:dep.

        ].

    ].

! !

!Object methodsFor:'dependents-interests'!

retractInterestsIn:aspect

    "remove all interests in the receiver changing aspect

     (as installed with #expressInterestIn:for:sendBack:)."

    "/ for now, remove the interestConverter.

    "/ In the future, a more intelligent DependencyCollection class is planned for

    self retractInterestsForWhich:[:i | i aspect == aspect ]

! !

!Object methodsFor:'dependents-st/v event simulation'!

when:eventSymbol send:selector to:anObject

    "install an ST/V-style interest forwarder.

     Here, we use the nonWeakDependencies."

    self addInterest:(InterestConverterWithParameters

                            destination:anObject 

                            selector:selector 

                            aspect:eventSymbol).

    "

     |p b|

     b := [Transcript showCR:'the point changed'].

     p := Point new.

     p whem:#foo:bar: send:#value:value: to:[:a :b | Transcript show:'foo: '; show:a; show:' bar: '; showCR:b].

     Transcript showCR:'now changing'.

     p triggerEvent:#foo:bar: withArguments:#('fooArg' 'barArg').

     p retracrtInterests.

    "

! !