QueryProcessor.java

package org.cdlib.xtf.textEngine;

import java.io.IOException;

/*
 * Copyright (c) 2004, Regents of the University of California
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - 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.
 * - Neither the name of the University of California nor the names of its
 *   contributors may be used to endorse or promote products derived from this
 *   software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 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 file created on Mar 1, 2005 by Martin Haye
 */

/**
 * Takes a QueryRequest, rewrites the queries if necessary to remove stop-
 * words and form bi-grams, then consults the index(es), and produces a
 * QueryResult.
 *
 * @author Martin Haye
 */
public abstract class QueryProcessor 
{
  /**
   * Takes a query request and handles searching the index and forming
   * the results.
   *
   * @param req   The request to process
   * @return      Zero or more document hits
   */
  public abstract QueryResult processRequest(QueryRequest req)
    throws IOException;

  /**
   * Optional method: hint to the query processor to clear any cached
   * index data, so that recently indexed documents will appear in
   * search results.
   */
  public void resetCache() {
  }
  
  /**
   * Optional method: set the XTF home directory (used for background
   * warming in the default query processor.)
   */
  public void setXtfHome(String homeDir) {
  }

  /**
   * Optional method: set the background warmer for indexes.
   */
  public void setIndexWarmer(IndexWarmer warmer) {
  }
}