/
BaseListenerObservable.kt
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/
BaseListenerObservable.kt
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/*
* Copyright 2019 Kaushik N. Sanji
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.mindorks.kaushiknsanji.instagram.demo.ui.base.listeners
import java.util.*
import java.util.concurrent.ConcurrentHashMap
/**
* Base class for Listener entities in the application.
*
* @param L The type of Listeners.
*
* @author Kaushik N Sanji
*/
open class BaseListenerObservable<L> : ListenerHost<L> {
// Thread-safe set of Listeners
private val listeners: MutableSet<L> = Collections.newSetFromMap(ConcurrentHashMap<L, Boolean>(1))
/**
* Registers a [listener] that will be notified of any events.
*
* @return `true` if the [listener] has been added, `false` if the [listener] was already registered.
*/
override fun registerListener(listener: L): Boolean = listeners.add(listener)
/**
* Unregisters a previously registered [listener]. Does nothing if the [listener] was not previously registered.
*
* @return `true` if the [listener] has been successfully removed; `false` if the [listener] was not previously registered.
*/
override fun unregisterListener(listener: L): Boolean = listeners.remove(listener)
/**
* Returns a read-only reference to the [Set] containing all the registered [listeners].
*/
fun getListeners(): Set<L> = Collections.unmodifiableSet(listeners)
}