/*
 * 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.search;


import java.io.IOException;

A FilterScorer contains another Scorer, which it uses as its basic source of data, possibly transforming the data along the way or providing additional functionality. The class FilterScorer itself simply implements all abstract methods of Scorer with versions that pass all requests to the contained scorer. Subclasses of FilterScorer may further override some of these methods and may also provide additional methods and fields. /** 
 * A {@code FilterScorer} contains another {@code Scorer}, which it
 * uses as its basic source of data, possibly transforming the data along the
 * way or providing additional functionality. The class
 * {@code FilterScorer} itself simply implements all abstract methods
 * of {@code Scorer} with versions that pass all requests to the
 * contained scorer. Subclasses of {@code FilterScorer} may
 * further override some of these methods and may also provide additional
 * methods and fields.
 */
public abstract class FilterScorer extends Scorer {
  protected final Scorer in;

  
Create a new FilterScorer
Params:
in – the Scorer to wrap/**
   * Create a new FilterScorer
   * @param in the {@link Scorer} to wrap
   */
  public FilterScorer(Scorer in) {
    super(in.weight);
    this.in = in;
  }

  
Create a new FilterScorer with a specific weight
Params:
in – the Scorer to wrap
weight – a Weight/**
   * Create a new FilterScorer with a specific weight
   * @param in the {@link Scorer} to wrap
   * @param weight a {@link Weight}
   */
  public FilterScorer(Scorer in, Weight weight) {
    super(weight);
    if (in == null) {
      throw new NullPointerException("wrapped Scorer must not be null");
    }
    this.in = in;
  }
  
  @Override
  public float score() throws IOException {
    return in.score();
  }

  // Leave maxScore abstract on purpose since the goal of this Filter class is
  // to change the way the score is computed.

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

  @Override
  public final DocIdSetIterator iterator() {
    return in.iterator();
  }
  
  @Override
  public final TwoPhaseIterator twoPhaseIterator() {
    return in.twoPhaseIterator();
  }
}