content: package org.apache.lucene.search;
  
  /**
   * 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.
   */
  
  import org.apache.lucene.index.IndexReader;
  import org.apache.lucene.index.Term;
  import org.apache.lucene.index.TermDocs;
  import org.apache.lucene.util.ToStringUtils;
  
  import java.util.Set;
  import java.io.IOException;
  
  /**
   * A query that matches all documents.
   *
   */
  public class MatchAllDocsQuery extends Query {
  
    public MatchAllDocsQuery() {
      this(null);
    }
  
    private final String normsField;
  
    /**
     * @param normsField Field used for normalization factor (document boost). Null if nothing.
     */
    public MatchAllDocsQuery(String normsField) {
      this.normsField = normsField;
    }
  
    private class MatchAllScorer extends Scorer {
      final TermDocs termDocs;
      final float score;
      final byte[] norms;
      private int doc = -1;
      
      MatchAllScorer(IndexReader reader, Similarity similarity, Weight w,
          byte[] norms) throws IOException {
        super(similarity,w);
        this.termDocs = reader.termDocs(null);
        score = w.getValue();
        this.norms = norms;
      }
  
      @Override
      public int docID() {
        return doc;
      }
  
      @Override
      public int nextDoc() throws IOException {
        return doc = termDocs.next() ? termDocs.doc() : NO_MORE_DOCS;
      }
      
      @Override
      public float score() {
        return norms == null ? score : score * getSimilarity().decodeNormValue(norms[docID()]);
      }
  
      @Override
      public int advance(int target) throws IOException {
        return doc = termDocs.skipTo(target) ? termDocs.doc() : NO_MORE_DOCS;
      }
    }
  
    private class MatchAllDocsWeight extends Weight {
      private Similarity similarity;
      private float queryWeight;
      private float queryNorm;
  
      public MatchAllDocsWeight(Searcher searcher) {
        this.similarity = searcher.getSimilarity();
      }
  
      @Override
      public String toString() {
        return "weight(" + MatchAllDocsQuery.this + ")";
      }
  
      @Override
      public Query getQuery() {
        return MatchAllDocsQuery.this;
      }
  
      @Override
      public float getValue() {
        return queryWeight;
      }
  
      @Override
      public float sumOfSquaredWeights() {
        queryWeight = getBoost();
        return queryWeight * queryWeight;
      }
  
      @Override
      public void normalize(float queryNorm) {
        this.queryNorm = queryNorm;
        queryWeight *= this.queryNorm;
      }
  
      @Override
      public Scorer scorer(IndexReader reader, boolean scoreDocsInOrder, boolean topScorer) throws IOException {
        return new MatchAllScorer(reader, similarity, this,
            normsField != null ? reader.norms(normsField) : null);
      }
  
      @Override
      public Explanation explain(IndexReader reader, int doc) {
        // explain query weight
        Explanation queryExpl = new ComplexExplanation
          (true, getValue(), "MatchAllDocsQuery, product of:");
        if (getBoost() != 1.0f) {
          queryExpl.addDetail(new Explanation(getBoost(),"boost"));
        }
        queryExpl.addDetail(new Explanation(queryNorm,"queryNorm"));
  
        return queryExpl;
      }
    }
  
    @Override
    public Weight createWeight(Searcher searcher) {
      return new MatchAllDocsWeight(searcher);
    }
  
    @Override
    public void extractTerms(Set<Term> terms) {
    }
  
    @Override
    public String toString(String field) {
      StringBuilder buffer = new StringBuilder();
      buffer.append("*:*");
      buffer.append(ToStringUtils.boost(getBoost()));
      return buffer.toString();
    }
  
    @Override
    public boolean equals(Object o) {
      if (!(o instanceof MatchAllDocsQuery))
        return false;
      MatchAllDocsQuery other = (MatchAllDocsQuery) o;
      return this.getBoost() == other.getBoost();
    }
  
    @Override
    public int hashCode() {
      return Float.floatToIntBits(getBoost()) ^ 0x1AA71190;
    }
  }
  