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 org.apache.kafka.streams.state.internals;
  
  import org.apache.kafka.common.utils.Bytes;
  import org.apache.kafka.streams.KeyValue;
  
  import java.util.NoSuchElementException;
  
  class FilteredCacheIterator implements PeekingKeyValueIterator<Bytes, LRUCacheEntry> {
      private final PeekingKeyValueIterator<Bytes, LRUCacheEntry> cacheIterator;
      private final HasNextCondition hasNextCondition;
      private final PeekingKeyValueIterator<Bytes, LRUCacheEntry> wrappedIterator;
  
      FilteredCacheIterator(final PeekingKeyValueIterator<Bytes, LRUCacheEntry> cacheIterator,
                            final HasNextCondition hasNextCondition,
                            final CacheFunction cacheFunction) {
          this.cacheIterator = cacheIterator;
          this.hasNextCondition = hasNextCondition;
          this.wrappedIterator = new PeekingKeyValueIterator<Bytes, LRUCacheEntry>() {
              @Override
              public KeyValue<Bytes, LRUCacheEntry> peekNext() {
                  return cachedPair(cacheIterator.peekNext());
              }
  
              @Override
              public void close() {
                  cacheIterator.close();
              }
  
              @Override
              public Bytes peekNextKey() {
                  return cacheFunction.key(cacheIterator.peekNextKey());
              }
  
              @Override
              public boolean hasNext() {
                  return cacheIterator.hasNext();
              }
  
              @Override
              public KeyValue<Bytes, LRUCacheEntry> next() {
                  return cachedPair(cacheIterator.next());
              }
  
              private KeyValue<Bytes, LRUCacheEntry> cachedPair(final KeyValue<Bytes, LRUCacheEntry> next) {
                  return KeyValue.pair(cacheFunction.key(next.key), next.value);
              }
  
          };
      }
  
      @Override
      public void close() {
          // no-op
      }
  
      @Override
      public Bytes peekNextKey() {
          if (!hasNext()) {
              throw new NoSuchElementException();
          }
          return cacheIterator.peekNextKey();
      }
  
      @Override
      public boolean hasNext() {
          return hasNextCondition.hasNext(wrappedIterator);
      }
  
      @Override
      public KeyValue<Bytes, LRUCacheEntry> next() {
          if (!hasNext()) {
              throw new NoSuchElementException();
          }
          return cacheIterator.next();
  
      }
  
      @Override
      public KeyValue<Bytes, LRUCacheEntry> peekNext() {
          if (!hasNext()) {
              throw new NoSuchElementException();
          }
          return cacheIterator.peekNext();
      }
  }
  