content: /*
   * Copyright (C) 2014 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.amnesica.kryptey.inputmethod.keyboard.internal;
  
  import com.amnesica.kryptey.inputmethod.keyboard.Key;
  
  import java.util.HashMap;
  
  public abstract class UniqueKeysCache {
    public abstract void setEnabled(boolean enabled);
  
    public abstract void clear();
  
    public abstract Key getUniqueKey(Key key);
  
    public static final UniqueKeysCache NO_CACHE = new UniqueKeysCache() {
      @Override
      public void setEnabled(boolean enabled) {
      }
  
      @Override
      public void clear() {
      }
  
      @Override
      public Key getUniqueKey(Key key) {
        return key;
      }
    };
  
    public static UniqueKeysCache newInstance() {
      return new UniqueKeysCacheImpl();
    }
  
    private static final class UniqueKeysCacheImpl extends UniqueKeysCache {
      private final HashMap<Key, Key> mCache;
  
      private boolean mEnabled;
  
      UniqueKeysCacheImpl() {
        mCache = new HashMap<>();
      }
  
      @Override
      public void setEnabled(final boolean enabled) {
        mEnabled = enabled;
      }
  
      @Override
      public void clear() {
        mCache.clear();
      }
  
      @Override
      public Key getUniqueKey(final Key key) {
        if (!mEnabled) {
          return key;
        }
        final Key existingKey = mCache.get(key);
        if (existingKey != null) {
          // Reuse the existing object that equals to "key" without adding "key" to
          // the cache.
          return existingKey;
        }
        mCache.put(key, key);
        return key;
      }
    }
  }
  