CombinedLoadStates.kt
/*
* Copyright 2020 The Android Open Source Project
*
* 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 androidx.paging
import androidx.annotation.RestrictTo
/**
* Collection of pagination [LoadState]s for both a [PagingSource], and [RemoteMediator].
*/
data class CombinedLoadStates(
/**
* [LoadStates] corresponding to loads from a [PagingSource].
*/
val source: LoadStates,
/**
* [LoadStates] corresponding to loads from a [RemoteMediator], or `null` if [RemoteMediator]
* not present.
*/
val mediator: LoadStates? = null
) {
/**
* Convenience for accessing [REFRESH][LoadType.REFRESH] [LoadState], which always defers to
* [LoadState] of [mediator] if it exists, otherwise equivalent to [LoadState] of [source].
*
* For use cases that require reacting to [LoadState] of [source] and [mediator]
* specifically, e.g., showing cached data when network loads via [mediator] fail,
* [LoadStates] exposed via [source] and [mediator] should be used directly.
*/
val refresh: LoadState = (mediator ?: source).refresh
/**
* Convenience for accessing [PREPEND][LoadType.PREPEND] [LoadState], which always defers to
* [LoadState] of [mediator] if it exists, otherwise equivalent to [LoadState] of [source].
*
* For use cases that require reacting to [LoadState] of [source] and [mediator]
* specifically, e.g., showing cached data when network loads via [mediator] fail,
* [LoadStates] exposed via [source] and [mediator] should be used directly.
*/
val prepend: LoadState = (mediator ?: source).prepend
/**
* Convenience for accessing [APPEND][LoadType.APPEND] [LoadState], which always defers to
* [LoadState] of [mediator] if it exists, otherwise equivalent to [LoadState] of [source].
*
* For use cases that require reacting to [LoadState] of [source] and [mediator]
* specifically, e.g., showing cached data when network loads via [mediator] fail,
* [LoadStates] exposed via [source] and [mediator] should be used directly.
*/
val append: LoadState = (mediator ?: source).append
@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
inline fun forEach(op: (LoadType, Boolean, LoadState) -> Unit) {
source.forEach { type, state ->
op(type, false, state)
}
mediator?.forEach { type, state ->
op(type, true, state)
}
}
internal companion object {
val IDLE_SOURCE = CombinedLoadStates(
source = LoadStates.IDLE
)
val IDLE_MEDIATOR = CombinedLoadStates(
source = LoadStates.IDLE,
mediator = LoadStates.IDLE
)
}
}