package org.apache.lucene.search;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache Lucene" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache Lucene", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

import java.io.IOException;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermDocs;
import org.apache.lucene.index.IndexReader;

/** A Query that matches documents containing a term.
  This may be combined with other terms with a {@link BooleanQuery}.
  */
public class TermQuery extends Query {
  private Term term;

  private class TermWeight implements Weight {
    private Searcher searcher;
    private float value;
    private float idf;
    private float queryNorm;

    public TermWeight(Searcher searcher) {
      this.searcher = searcher;
    }

    public Query getQuery() { return TermQuery.this; }
    public float getValue() { return value; }

    public float sumOfSquaredWeights() throws IOException {
      idf = searcher.getSimilarity().idf(term, searcher);
      value = idf * getBoost();
      return value * value;			  // square term weights
    }

    public void normalize(float norm) {
      queryNorm = norm;
      queryNorm *= idf;                           // factor from document
      value *= queryNorm;                         // normalize for query
    }

    public Scorer scorer(IndexReader reader) throws IOException {
      TermDocs termDocs = reader.termDocs(term);
      
      if (termDocs == null)
        return null;
      
      return new TermScorer(this, termDocs, searcher.getSimilarity(),
                            reader.norms(term.field()));
    }

    public Explanation explain() throws IOException {
      Query q = getQuery();

      Explanation result = new Explanation();
      result.setDescription("weight(" + getQuery() + "), product of:");

      Explanation boostExpl = new Explanation(getBoost(), "boost");
      if (getBoost() != 1.0f)
        result.addDetail(boostExpl);
      
      Explanation idfExpl =
        new Explanation(idf, "idf(docFreq=" + searcher.docFreq(term) + ")");
      result.addDetail(idfExpl);
      
      Explanation normExpl = new Explanation(queryNorm,"queryNorm");
      result.addDetail(normExpl);

      result.setValue(boostExpl.getValue() *
                      idfExpl.getValue() *
                      normExpl.getValue());

      return result;
    }
  }

  /** Constructs a query for the term <code>t</code>. */
  public TermQuery(Term t) {
    term = t;
  }

  /** Returns the term of this query. */
  public Term getTerm() { return term; };

  protected Weight createWeight(Searcher searcher) {
    return new TermWeight(searcher);
  }

  /** Prints a user-readable version of this query. */
  public String toString(String field) {
    StringBuffer buffer = new StringBuffer();
    if (!term.field().equals(field)) {
      buffer.append(term.field());
      buffer.append(":");
    }
    buffer.append(term.text());
    if (getBoost() != 1.0f) {
      buffer.append("^");
      buffer.append(Float.toString(getBoost()));
    }
    return buffer.toString();
  }

  /** Returns true iff <code>o</code> is equal to this. */
  public boolean equals(Object o) {
    if (!(o instanceof TermQuery))
      return false;
    TermQuery other = (TermQuery)o;
    return (this.getBoost() == other.getBoost())
      && this.term.equals(other.term);
  }

  /** Returns a hash code value for this object.*/
  public int hashCode() {
    return Float.floatToIntBits(getBoost()) ^ term.hashCode();
  }

}

@@ -5065,17 +5065,16 @@
  term; %7D
-;
 %0A%0A  prot

- Removed erroneous semicolon.