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.calcite.linq4j;
  
  /**
   * Enumerable that has a (limited) memory for n past and m future steps.
   *
   * @param <E> Type of the Enumerable items to remember
   */
  public class MemoryEnumerable<E> extends AbstractEnumerable<MemoryFactory.Memory<E>> {
    private final Enumerable<E> input;
    private final int history;
    private final int future;
  
    /**
     * Creates a MemoryEnumerable.
     *
     * @param input The Enumerable which the memory should be "wrapped" around
     * @param history Number of present steps to remember
     * @param future Number of future steps to remember
     */
    MemoryEnumerable(Enumerable<E> input, int history, int future) {
      this.input = input;
      this.history = history;
      this.future = future;
    }
  
    @Override public Enumerator<MemoryFactory.Memory<E>> enumerator() {
      return new MemoryEnumerator<>(input.enumerator(), history, future);
    }
  
  }
  