commonMain.jetbrains.datalore.base.observable.property.DelayedValueProperty.kt Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of lets-plot-common Show documentation

Lets-Plot JVM package without rendering part

There is a newer version: 4.5.3-alpha1

/*
 * Copyright (c) 2020. JetBrains s.r.o.
 * Use of this source code is governed by the MIT license that can be found in the LICENSE file.
 */

package jetbrains.datalore.base.observable.property

import jetbrains.datalore.base.observable.event.EventHandler
import jetbrains.datalore.base.observable.event.ListenerCaller
import jetbrains.datalore.base.observable.event.Listeners
import jetbrains.datalore.base.registration.Registration
import kotlin.jvm.JvmOverloads

class DelayedValueProperty
@JvmOverloads
constructor(
        private var myValue: ValueT? = null) :
        BaseReadableProperty(),
    Property {

    private var myHandlers: Listeners>>? = null
    private var myPendingEvent: PropertyChangeEvent? = null

    override val propExpr: String
        get() = "delayedProperty()"

    override fun get(): ValueT? {
        return myValue
    }

    override fun set(value: ValueT?) {
        if (value == myValue) return
        val oldValue = myValue
        myValue = value

        if (myPendingEvent != null) {
            throw IllegalStateException()
        }
        myPendingEvent =
            PropertyChangeEvent(oldValue, myValue)
    }

    fun flush() {
        if (myHandlers != null) {
            myHandlers!!.fire(object : ListenerCaller>> {
                override fun call(l: EventHandler>) {
                    l.onEvent(myPendingEvent!!)
                }
            })
        }
        myPendingEvent = null
    }

    override fun addHandler(handler: EventHandler>): Registration {
        if (myHandlers == null) {
            myHandlers = object : Listeners>>() {
                override fun afterLastRemoved() {
                    myHandlers = null
                }
            }
        }
        return myHandlers!!.add(handler)
    }
}