org.apache.calcite.linq4j.MemoryEnumerable Maven / Gradle / Ivy
/*
* 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 Type of the Enumerable items to remember
*/
public class MemoryEnumerable extends AbstractEnumerable> {
private final Enumerable 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 input, int history, int future) {
this.input = input;
this.history = history;
this.future = future;
}
@Override public Enumerator> enumerator() {
return new MemoryEnumerator<>(input.enumerator(), history, future);
}
}