/*
    * Copyright 2020-2022 The OSHI Project Contributors
    * SPDX-License-Identifier: MIT
    */
   package oshi.driver.windows.perfmon;
   
   import static oshi.driver.windows.perfmon.PerfmonConstants.MEMORY;
   import static oshi.driver.windows.perfmon.PerfmonConstants.WIN32_PERF_RAW_DATA_PERF_OS_MEMORY;
   
  import java.util.Collections;
  import java.util.Map;
  
  import oshi.annotation.concurrent.ThreadSafe;
  import oshi.util.platform.windows.PerfCounterQuery;
  import oshi.util.platform.windows.PerfCounterQuery.PdhCounterProperty;
  
  /**
   * Utility to query Memory performance counter
   */
  @ThreadSafe
  public final class MemoryInformation {
  
      /**
       * For pages in/out
       */
      public enum PageSwapProperty implements PdhCounterProperty {
          PAGESINPUTPERSEC(null, "Pages Input/sec"), //
          PAGESOUTPUTPERSEC(null, "Pages Output/sec");
  
          private final String instance;
          private final String counter;
  
          PageSwapProperty(String instance, String counter) {
              this.instance = instance;
              this.counter = counter;
          }
  
          @Override
          public String getInstance() {
              return instance;
          }
  
          @Override
          public String getCounter() {
              return counter;
          }
      }
  
      private MemoryInformation() {
      }
  
      /**
       * Returns page swap counters
       *
       * @return Page swap counters for memory.
       */
      public static Map<PageSwapProperty, Long> queryPageSwaps() {
          if (PerfmonDisabled.PERF_OS_DISABLED) {
              return Collections.emptyMap();
          }
          return PerfCounterQuery.queryValues(PageSwapProperty.class, MEMORY, WIN32_PERF_RAW_DATA_PERF_OS_MEMORY);
      }
  }