org.jitsi.metaconfig.supplier.FallbackSupplier.kt Maven / Gradle / Ivy

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/*
 * Copyright @ 2018 - present 8x8, Inc.
 *
 * 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.jitsi.metaconfig.supplier

import org.jitsi.metaconfig.ConfigException
import org.jitsi.metaconfig.Deprecation
import org.jitsi.metaconfig.MetaconfigSettings
import org.jitsi.metaconfig.noDeprecation

/**
 * A [ConfigValueSupplier] which searches through multiple [ConfigValueSupplier]s, in order,
 * to find a value.
 *
 * Note that a [FallbackSupplier] is never deprecated, only the suppliers it checks can be,
 * so we also pass [noDeprecation] to [ConfigValueSupplier].
 */
class FallbackSupplier(
    private val suppliers: List>
) : ConfigValueSupplier() {

    override fun doGet(): ValueType {
        MetaconfigSettings.logger.debug {
            "${this::class.simpleName}: checking for value via suppliers:" +
                suppliers.joinToString(prefix = "\n  ", separator = "\n  ")
        }
        val exceptions = mutableListOf()
        for (supplier in suppliers) {
            try {
                return supplier.get().also {
                    MetaconfigSettings.logger.debug {
                        "${this::class.simpleName}: value found via $supplier"
                    }
                }
            } catch (e: ConfigException.UnableToRetrieve.Deprecated) {
                throw e
            } catch (e: ConfigException.UnableToRetrieve) {
                MetaconfigSettings.logger.debug {
                    "${this::class.simpleName}: failed to find value via $supplier: $e"
                }
                exceptions += e
            }
        }
        throw ConfigException.UnableToRetrieve.NotFound(
            "No suppliers found a value:${exceptions.joinToString(prefix = "\n  ", separator = "\n  ")}"
        )
    }

    override fun withDeprecation(deprecation: Deprecation): FallbackSupplier =
        FallbackSupplier(suppliers.map { it.withDeprecation(deprecation) })

    override fun toString(): String = "${this::class.simpleName}: checking suppliers:" +
        suppliers.joinToString(prefix = "\n  ", separator = "\n  ")
}