Service Locator's imple

Sl.kt

package com.yibo.housekeeping.test

import android.annotation.SuppressLint
import android.content.Context
import android.support.annotation.NonNull
import android.support.annotation.Nullable

/**
 * @author LouisShark
 * @date 2018/8/4.
 * this is on com.yibo.housekeeping.test.
 */
class Sl private constructor() {
	interface IService
	interface Creator<out T> {
		fun newInstance(@NonNull context: Context): T
	}

	companion object {
		private val sServicesInstances = HashMap<String, Any>()
		private val sServicesImplementationsMapping = HashMap<String, Class<*>>()
		@SuppressLint("StaticFieldLeak")
		private lateinit var mContext: Context
		private val sServicesInstancesLock = Any()

		fun init(@NonNull context: Context) {
			mContext = context.applicationContext
		}

		/**
		 * Return instance of desired class or object that implement desired interface.
		 */
		@Suppress("UNCHECKED_CAST")
		fun <T> get(@NonNull clazz: Class<T>): T {
			val instance = getService(clazz.name, mContext)
			return instance as T
		}

		/**
		 * This method allows to bind a custom service implementation to an interface.
		 *
		 * @param interfaceClass      interface
		 * @param implementationClass class which implement interface specified in first param
		 */
		fun bindCustomServiceImplementation(
			interfaceClass: Class<*>,
			implementationClass: Class<*>
		) {
			synchronized(sServicesInstancesLock) {
				sServicesImplementationsMapping.put(interfaceClass.name, implementationClass)
			}
		}

		@NonNull
		private fun getService(@NonNull name: String, @Nullable applicationContext: Context): Any {
			synchronized(sServicesInstancesLock) {
				return sServicesInstances[name] ?: try {
					val clazz: Class<*> =
						if (sServicesImplementationsMapping.containsKey(name)) {
							sServicesImplementationsMapping[name]!!
						} else {
							Class.forName(name)
						}
					val serviceInstance = try {
						clazz.getDeclaredConstructor(Context::class.java)
							.newInstance(applicationContext)
					} catch (e: NoSuchMethodException) {
						clazz.getDeclaredConstructor().newInstance()
					} as? Sl.IService
							?: throw IllegalArgumentException("Required service must implement IService interface")
					sServicesInstances[name] = serviceInstance
					return serviceInstance
				} catch (e: ClassNotFoundException) {
					throw IllegalArgumentException(
						"Requested service class was not found: $name",
						e
					)
				} catch (e: Exception) {
					throw IllegalArgumentException(
						"Cannot initialize requested service: $name",
						e
					)
				}
			}
		}


	}


}