lucene/queries/src/java/org/apache/lucene/queries/intervals/IntervalFilter.java

/*
 * 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.lucene.queries.intervals;

import java.io.IOException;
import java.util.Objects;

/**
 * Wraps an {@link IntervalIterator} and passes through those intervals that match the {@link #accept()} function
 */
public abstract class IntervalFilter extends IntervalIterator {

  protected final IntervalIterator in;

  /**
   * Create a new filter
   */
  public IntervalFilter(IntervalIterator in) {
    this.in = Objects.requireNonNull(in);
  }

  @Override
  public int docID() {
    return in.docID();
  }

  @Override
  public int nextDoc() throws IOException {
    return in.nextDoc();
  }

  @Override
  public int advance(int target) throws IOException {
    return in.advance(target);
  }

  @Override
  public long cost() {
    return in.cost();
  }

  @Override
  public int start() {
    return in.start();
  }

  @Override
  public int end() {
    return in.end();
  }

  @Override
  public int gaps() {
    return in.gaps();
  }

  @Override
  public float matchCost() {
    return in.matchCost();
  }

  /**
   * @return {@code true} if the wrapped iterator's interval should be passed on
   */
  protected abstract boolean accept();

  @Override
  public final int nextInterval() throws IOException {
    int next;
    do {
      next = in.nextInterval();
    }
    while (next != IntervalIterator.NO_MORE_INTERVALS && accept() == false);
    return next;
  }

}