PageSelector.java

package org.cdlib.xtf.textEngine.facet;


/*
 * 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.
 */

/** Select page sets of siblings around selected groups */
public class PageSelector extends GroupSelector 
{
  private int pageSize = 10;

  public void setPageSize(int pageSize) {
    this.pageSize = pageSize;
  }

  public void process(int group) 
  {
    int lastPageStart = -1;

    // In conservative mode, select everything.
    if (conservative) {
      next.process(group);
      return;
    }

    // Figure out which page this group is on among its siblings.
    int parent = counts.parent(group);
    int n = 0;
    for (int kid = counts.child(parent); kid >= 0; kid = counts.sibling(kid)) {
      if (!counts.shouldInclude(kid))
        continue;
      if ((n % pageSize) == 0)
        lastPageStart = kid;
      if (kid == group)
        break;
      ++n;
    }
    assert lastPageStart >= 0 : "incorrect tree data";

    // Now select everything on this page.
    n = 0;
    for (int kid = lastPageStart; kid >= 0; kid = counts.sibling(kid)) {
      next.process(kid);
      ++n;
      if (n == pageSize)
        break;
    }
  } // process()

  public String toString() {
    return "page(" + pageSize + ") -> " + next.toString();
  }
}