content: /*
   * Copyright (C) 2016 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 com.android.server.wifi.hotspot2;
  
  import com.android.internal.annotations.VisibleForTesting;
  import com.android.server.wifi.Clock;
  import com.android.server.wifi.hotspot2.anqp.ANQPElement;
  import com.android.server.wifi.hotspot2.anqp.Constants;
  
  import java.io.PrintWriter;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * Cache for storing ANQP data.  This is simply a data cache, all the logic related to
   * ANQP data query will be handled elsewhere (e.g. the consumer of the cache).
   */
  public class AnqpCache {
      @VisibleForTesting
      public static final long CACHE_SWEEP_INTERVAL_MILLISECONDS = 60000L;
  
      private long mLastSweep;
      private Clock mClock;
  
      private final Map<ANQPNetworkKey, ANQPData> mANQPCache;
  
      public AnqpCache(Clock clock) {
          mClock = clock;
          mANQPCache = new HashMap<>();
          mLastSweep = mClock.getElapsedSinceBootMillis();
      }
  
      /**
       * Add an ANQP entry associated with the given key.
       *
       * @param key The key that's associated with the entry
       * @param anqpElements The ANQP elements from the AP
       */
      public void addEntry(ANQPNetworkKey key,
              Map<Constants.ANQPElementType, ANQPElement> anqpElements) {
          ANQPData data = new ANQPData(mClock, anqpElements);
          mANQPCache.put(key, data);
      }
  
      /**
       * Get the ANQP data associated with the given AP.
       *
       * @param key The key that's associated with the entry
       * @return {@link ANQPData}
       */
      public ANQPData getEntry(ANQPNetworkKey key) {
          return mANQPCache.get(key);
      }
  
      /**
       * Go through the cache to remove any expired entries.
       */
      public void sweep() {
          long now = mClock.getElapsedSinceBootMillis();
          // Check if it is time to perform the sweep.
          if (now < mLastSweep + CACHE_SWEEP_INTERVAL_MILLISECONDS) {
              return;
          }
  
          // Get all expired keys.
          List<ANQPNetworkKey> expiredKeys = new ArrayList<>();
          for (Map.Entry<ANQPNetworkKey, ANQPData> entry : mANQPCache.entrySet()) {
              if (entry.getValue().expired(now)) {
                  expiredKeys.add(entry.getKey());
              }
          }
  
          // Remove all expired entries.
          for (ANQPNetworkKey key : expiredKeys) {
              mANQPCache.remove(key);
          }
          mLastSweep = now;
      }
  
      public void dump(PrintWriter out) {
          out.println("Last sweep " + Utils.toHMS(mClock.getElapsedSinceBootMillis() - mLastSweep)
                  + " ago.");
          for (Map.Entry<ANQPNetworkKey, ANQPData> entry : mANQPCache.entrySet()) {
              out.println(entry.getKey() + ": " + entry.getValue());
          }
      }
  }
  