TermDocs.cs :  » Search-Engines » dotLucene » Lucene » Net » Index » C# / CSharp Open Source

/*
 * Copyright 2004 The Apache Software Foundation
 * 
 * Licensed 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.
 */

using System;

namespace Lucene.Net.Index{
  
  /// <summary>TermDocs provides an interface for enumerating &lt;document, frequency&gt;
  /// pairs for a term.  <p> The document portion names each document containing
  /// the term.  Documents are indicated by number.  The frequency portion gives
  /// the number of times the term occurred in each document.  <p> The pairs are
  /// ordered by document number.
  /// </summary>
  /// <seealso cref="IndexReader.TermDocs()">
  /// </seealso>
  
  public interface TermDocs
  {
    /// <summary>Sets this to the data for a term.
    /// The enumeration is reset to the start of the data for this term.
    /// </summary>
    void  Seek(Term term);
    
    /// <summary>Sets this to the data for the current term in a {@link TermEnum}.
    /// This may be optimized in some implementations.
    /// </summary>
    void  Seek(TermEnum termEnum);
    
    /// <summary>Returns the current document number.  <p> This is invalid until {@link
    /// #Next()} is called for the first time.
    /// </summary>
    int Doc();
    
    /// <summary>Returns the frequency of the term within the current document.  <p> This
    /// is invalid until {@link #Next()} is called for the first time.
    /// </summary>
    int Freq();
    
    /// <summary>Moves to the next pair in the enumeration.  <p> Returns true iff there is
    /// such a next pair in the enumeration. 
    /// </summary>
    bool Next();
    
    /// <summary>Attempts to read multiple entries from the enumeration, up to length of
    /// <i>docs</i>.  Document numbers are stored in <i>docs</i>, and term
    /// frequencies are stored in <i>freqs</i>.  The <i>freqs</i> array must be as
    /// long as the <i>docs</i> array.
    /// 
    /// <p>Returns the number of entries read.  Zero is only returned when the
    /// stream has been exhausted.  
    /// </summary>
    int Read(int[] docs, int[] freqs);
    
    /// <summary>Skips entries to the first beyond the current whose document number is
    /// greater than or equal to <i>target</i>. <p>Returns true iff there is such
    /// an entry.  <p>Behaves as if written: <pre>
    /// boolean skipTo(int target) {
    /// do {
    /// if (!next())
    /// return false;
    /// } while (target > doc());
    /// return true;
    /// }
    /// </pre>
    /// Some implementations are considerably more efficient than that.
    /// </summary>
    bool SkipTo(int target);
    
    /// <summary>Frees associated resources. </summary>
    void  Close();
  }
}