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Lock-free document store—optimized for high rate atomic state changes—that concurrently commits and compacts on-disk log-structured storage files without blocking parallel in-memory updates to associative B-tree maps, spatial Q-tree maps, sequential S-tree lists, and singleton U-tree values

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// Copyright 2015-2024 Nstream, 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 swim.db;

import swim.concurrent.Stage;
import swim.structure.Record;
import swim.structure.Value;

public class PageContext {

  public PageContext() {
    // nop
  }

  public StoreSettings settings() {
    return StoreSettings.standard();
  }

  public Stage stage() {
    throw new UnsupportedOperationException();
  }

  public boolean pageShouldSplit(Page page) {
    return PageContext.pageShouldSplit(page, this.settings().pageSplitSize);
  }

  public boolean pageShouldMerge(Page page) {
    return PageContext.pageShouldMerge(page, this.settings().pageSplitSize);
  }

  public PageLoader openPageLoader(boolean isResident) {
    throw new UnsupportedOperationException();
  }

  public void hitPage(Page page) {
    // nop
  }

  public Value reduce(Record record) {
    return Value.absent();
  }

  public static boolean pageShouldSplit(Page page, int pageSplitSize) {
    return page.pageSize() > pageSplitSize;
  }

  public static boolean pageShouldMerge(Page page, int pageSplitSize) {
    return page.pageSize() < pageSplitSize >>> 1;
  }

}