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/*
 * @(#) DefaultValue.kt
 *
 * json-kotlin-schema-codegen  JSON Schema Code Generation
 * Copyright (c) 2022 Peter Wall
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package net.pwall.util

import kotlin.reflect.KProperty

/**
 * Delegate class for properties that have a default value if not otherwise initialised.
 *
 * @author  Peter Wall
 * @param   T       the value type
 */
class DefaultValue(
    private var value: T? = null,
    private val initialiser: () -> T,
) {

    operator fun getValue(thisRef: Any?, property: KProperty<*>): T = value ?: initialiser().also { value = it }

    operator fun setValue(thisRef: Any?, property: KProperty<*>, value: T) {
        this.value = value
    }

}