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SingleDefinitionInstance.kt
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SingleDefinitionInstance.kt
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/*
* Copyright 2017-2018 the original author or authors.
*
* 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 org.koin.core.instance
import org.koin.core.definition.BeanDefinition
/**
* Single instance holder
* @author Arnaud Giuliani
*/
class SingleDefinitionInstance<T>(beanDefinition: BeanDefinition<T>) : DefinitionInstance<T>(beanDefinition) {
private var value: T? = null
override fun isCreated(context: InstanceContext): Boolean = (value != null)
override fun release(context: InstanceContext) {}
override fun close() {
beanDefinition.onClose?.invoke(value)
value = null
}
@Suppress("UNCHECKED_CAST")
override fun <T> get(context: InstanceContext): T {
if (value == null) {
value = create(context)
}
return value as? T ?: error("Single instance created couldn't return value")
}
}