content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 com.datastax.oss.driver.internal.core;
  
  import com.datastax.oss.driver.api.core.AsyncPagingIterable;
  import com.datastax.oss.driver.api.core.cql.ColumnDefinitions;
  import com.datastax.oss.driver.api.core.cql.ExecutionInfo;
  import com.datastax.oss.driver.shaded.guava.common.base.Preconditions;
  import edu.umd.cs.findbugs.annotations.NonNull;
  import java.util.ArrayDeque;
  import java.util.Collections;
  import java.util.List;
  import java.util.Queue;
  import java.util.concurrent.CompletableFuture;
  import java.util.concurrent.CompletionStage;
  
  public class MockAsyncPagingIterable<ElementT>
      implements AsyncPagingIterable<ElementT, MockAsyncPagingIterable<ElementT>> {
  
    private final Queue<ElementT> currentPage;
    private final MockAsyncPagingIterable<ElementT> nextPage;
  
    public MockAsyncPagingIterable(List<ElementT> elements, int fetchSize, boolean addEmptyLastPage) {
      if (elements.size() <= fetchSize) {
        currentPage = new ArrayDeque<>(elements);
        nextPage =
            addEmptyLastPage
                ? new MockAsyncPagingIterable<>(Collections.emptyList(), fetchSize, false)
                : null;
      } else {
        currentPage = new ArrayDeque<>(elements.subList(0, fetchSize));
        nextPage =
            new MockAsyncPagingIterable<>(
                elements.subList(fetchSize, elements.size()), fetchSize, addEmptyLastPage);
      }
    }
  
    @NonNull
    @Override
    public Iterable<ElementT> currentPage() {
      return currentPage;
    }
  
    @Override
    public int remaining() {
      return currentPage.size();
    }
  
    @Override
    public boolean hasMorePages() {
      return nextPage != null;
    }
  
    @NonNull
    @Override
    public CompletionStage<MockAsyncPagingIterable<ElementT>> fetchNextPage()
        throws IllegalStateException {
      Preconditions.checkState(nextPage != null);
      return CompletableFuture.completedFuture(nextPage);
    }
  
    @NonNull
    @Override
    public ColumnDefinitions getColumnDefinitions() {
      throw new UnsupportedOperationException("irrelevant");
    }
  
    @NonNull
    @Override
    public ExecutionInfo getExecutionInfo() {
      throw new UnsupportedOperationException("irrelevant");
    }
  
    @Override
    public boolean wasApplied() {
      throw new UnsupportedOperationException("irrelevant");
    }
  }
  