android.arch.paging.ListDataSource Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of kripton-arch-integration Show documentation

Kripton Arch Integration Library

There is a newer version: 8.2.0-rc.4

Show newest version

/*
 * Copyright 2016-2019 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 android.arch.paging;

import androidx.annotation.NonNull;

import java.util.ArrayList;
import java.util.List;

class ListDataSource extends PositionalDataSource {
    private final List mList;

    public ListDataSource(List list) {
        mList = new ArrayList<>(list);
    }

    @Override
    public void loadInitial(@NonNull LoadInitialParams params,
            @NonNull LoadInitialCallback callback) {
        final int totalCount = mList.size();

        final int position = computeInitialLoadPosition(params, totalCount);
        final int loadSize = computeInitialLoadSize(params, position, totalCount);

        // for simplicity, we could return everything immediately,
        // but we tile here since it's expected behavior
        List sublist = mList.subList(position, position + loadSize);
        callback.onResult(sublist, position, totalCount);
    }

    @Override
    public void loadRange(@NonNull LoadRangeParams params,
            @NonNull LoadRangeCallback callback) {
        callback.onResult(mList.subList(params.startPosition,
                params.startPosition + params.loadSize));
    }
}