group.java

Java的Web报表库

/**
 * ========================================
 * JFreeReport : a free Java report library
 * ========================================
 *
 * Project Info:  http://www.jfree.org/jfreereport/index.html
 * Project Lead:  Thomas Morgner;
 *
 * (C) Copyright 2000-2003, by Simba Management Limited and Contributors.
 *
 * This library is free software; you can redistribute it and/or modify it under the terms
 * of the GNU Lesser General Public License as published by the Free Software Foundation;
 * either version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with this
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * ----------
 * Group.java
 * ----------
 * (C)opyright 2000-2003, by Simba Management Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Simba Management Limited);
 * Contributor(s):   Thomas Morgner;
 *
 * $Id: Group.java,v 1.30.2.2 2003/08/24 14:17:59 taqua Exp $
 *
 * Changes (from 8-Feb-2002)
 * -------------------------
 * 08-Feb-2002 : Updated code to work with latest version of the JCommon class library (DG);
 * 11-May-2002 : Fields are now in a list, order is important for comparision. The field list
 *               not modifyable outside this list. Header and footer are no longer allowed to
 *               contain null values. Is lastItemInGroup returns always true, if the end of the
 *               data had been reached.
 * 03-Jul-2002 : Serializable and cloneable, replaces own ReadOnlyList with standard implementation
 * 26-Jul-2002 : Introduced DataRowBackend as replacement for the raw data access
 * 05-Sep-2002 : Documentation
 * 09-Sep-2002 : Removed log messages
 * 13-Sep-2002 : Ran checkstyle against the source
 * 02-Dec-2002 : Removed To-Do item, caching of field-name to index pos is done.
 * 06-Dec-2002 : Updated changelog, removed Iterator-usage for performance reasons
 * 10-Dec-2002 : Updated Javadocs (DG);
 *
 */

package com.jrefinery.report;

import java.io.Serializable;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.TreeSet;

import com.jrefinery.report.targets.style.StyleSheetCollection;
import com.jrefinery.report.targets.style.StyleSheetCollectionHelper;

/**
 * A report group.  Reports can contain any number of (nested) groups.
 * The order of the fields is important. If the group does not contain
 * any fields, the group spans the whole report from the first to the last
 * row.
 * <p>
 * The group's field list should not be modified after the group was added
 * to the group list, or the results are undefined.
 *
 * @see GroupList
 *
 * @author David Gilbert
 * @author Thomas Morgner
 */
public class Group implements Serializable, Cloneable, Comparable
{
  /**
   * Internal helper class to handle the style sheet collection properly.
   */
  private static class GroupStyleSheetCollectionHelper extends StyleSheetCollectionHelper
  {
    /** The group for which we handle the stylesheet collection. */
    private Group group;

    /**
     * Creates a new helper for the given group.
     *
     * @param group the group whose stylesheet collection should be managed.
     */
    public GroupStyleSheetCollectionHelper(final Group group)
    {
      this.group = group;
    }

    /**
     * Handles the stylesheet collection registration for the group and
     * all group bands.
     */
    protected void handleRegisterStyleSheetCollection()
    {
      group.getFooter().registerStyleSheetCollection(this.getStyleSheetCollection());
      group.getHeader().registerStyleSheetCollection(this.getStyleSheetCollection());
    }

    /**
     * Handles the stylesheet collection unregistration for the group and
     * all group bands.
     */
    protected void handleUnregisterStyleSheetCollection()
    {
      group.getFooter().unregisterStyleSheetCollection(this.getStyleSheetCollection());
      group.getHeader().unregisterStyleSheetCollection(this.getStyleSheetCollection());
    }
  }

  /** The name of the group. */
  private String name;

  /** The fields that define the group (can be empty). */
  private TreeSet fields;

  /** Cached fields. */
  private transient String[] fieldsCached;

  /** The group header (optional). */
  private GroupHeader header;

  /** The group footer (optional). */
  private GroupFooter footer;

  /** The helper implementation that manages the stylesheet collection. */
  private GroupStyleSheetCollectionHelper styleSheetCollectionHelper;

  /**
   * Constructs a group with no fields, and an empty header and footer.
   */
  public Group()
  {
    name = "anonymousGroup@" + super.hashCode();
    fields = new TreeSet();
    this.styleSheetCollectionHelper = new GroupStyleSheetCollectionHelper(this);
    this.footer = new GroupFooter();
    this.header = new GroupHeader();
  }

  /**
   * Defines the name for this group. The name must not be empty and must be unique within
   * the GroupList.
   *
   * @param name  the group name (null not permitted).
   */
  public void setName(final String name)
  {
    if (name == null)
    {
      throw new NullPointerException("Name must not be null");
    }

    this.name = name;
  }

  /**
   * Returns the name of the group.
   *
   * @return the group name.
   */
  public String getName()
  {
    return this.name;
  }

  /**
   * Returns the group header.
   * <P>
   * The group header is a report band that contains elements that should be printed at the
   * start of a group.
   *
   * @return the group header.
   */
  public GroupHeader getHeader()
  {
    return header;
  }

  /**
   * Sets the header for the group.
   *
   * @param header  the header (null not permitted).
   *
   * @throws NullPointerException if the given header is null
   */
  public void setHeader(final GroupHeader header)
  {
    if (header == null)
    {
      throw new NullPointerException("Header must not be null");
    }
    if (getStyleSheetCollection() != null)
    {
      this.header.unregisterStyleSheetCollection(getStyleSheetCollection());
    }
    this.header = header;
    if (getStyleSheetCollection() != null)
    {
      this.header.registerStyleSheetCollection(getStyleSheetCollection());
    }
  }

  /**
   * Returns the group footer.
   *
   * @return the footer.
   */
  public GroupFooter getFooter()
  {
    return footer;
  }

  /**
   * Sets the footer for the group.
   *
   * @param footer  the footer (null not permitted).
   * @throws NullPointerException if the given footer is null.
   */
  public void setFooter(final GroupFooter footer)
  {
    if (footer == null)
    {
      throw new NullPointerException("The footer must not be null");
    }
    if (getStyleSheetCollection() != null)
    {
      this.footer.unregisterStyleSheetCollection(getStyleSheetCollection());
    }
    this.footer = footer;
    if (getStyleSheetCollection() != null)
    {
      this.footer.registerStyleSheetCollection(getStyleSheetCollection());
    }
  }

  /**
   * Sets the fields for this group. The given list must contain Strings defining the
   * needed fields from the DataRow. Don't reference Function-Fields here, functions are
   * not supported in th groupfield definition.
   *
   * @param c  the list containing strings.
   *
   * @throws NullPointerException if the given list is null or the list contains null-values.