001    /**
002     * ========================================
003     * JFreeReport : a free Java report library
004     * ========================================
005     *
006     * Project Info:  http://reporting.pentaho.org/
007     *
008     * (C) Copyright 2000-2007, by Object Refinery Limited, Pentaho Corporation and Contributors.
009     *
010     * This library is free software; you can redistribute it and/or modify it under the terms
011     * of the GNU Lesser General Public License as published by the Free Software Foundation;
012     * either version 2.1 of the License, or (at your option) any later version.
013     *
014     * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
015     * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
016     * See the GNU Lesser General Public License for more details.
017     *
018     * You should have received a copy of the GNU Lesser General Public License along with this
019     * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
020     * Boston, MA 02111-1307, USA.
021     *
022     * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
023     * in the United States and other countries.]
024     *
025     * ------------
026     * $Id: LayoutController.java 2725 2007-04-01 18:49:29Z taqua $
027     * ------------
028     * (C) Copyright 2000-2005, by Object Refinery Limited.
029     * (C) Copyright 2005-2007, by Pentaho Corporation.
030     */
031    package org.jfree.report.flow.layoutprocessor;
032    
033    import org.jfree.report.DataSourceException;
034    import org.jfree.report.ReportDataFactoryException;
035    import org.jfree.report.ReportProcessingException;
036    import org.jfree.report.flow.FlowController;
037    import org.jfree.report.flow.ReportTarget;
038    
039    /**
040     * The layout controller iterates over the report layout. It uses a flow
041     * controller to query the data.
042     *
043     * @author Thomas Morgner
044     */
045    public interface LayoutController extends Cloneable
046    {
047      /**
048       * Retrieves the parent of this layout controller. This allows childs to query
049       * their context.
050       *
051       * @return the layout controller's parent to <code>null</code> if there is no
052       * parent.
053       */
054      public LayoutController getParent();
055    
056      /**
057       * Initializes the layout controller. This method is called exactly once. It
058       * is the creators responsibility to call this method.
059       * <p/>
060       * Calling initialize after the first advance must result in a
061       * IllegalStateException.
062       *
063       * @param node           the currently processed object or layout node.
064       * @param flowController the current flow controller.
065       * @param parent         the parent layout controller that was responsible for
066       *                       instantiating this controller.
067       * @throws DataSourceException        if there was a problem reading data from
068       *                                    the datasource.
069       * @throws ReportProcessingException  if there was a general problem during
070       *                                    the report processing.
071       * @throws ReportDataFactoryException if a query failed.
072       */
073      public void initialize(final Object node,
074                             final FlowController flowController,
075                             final LayoutController parent)
076          throws DataSourceException, ReportDataFactoryException,
077          ReportProcessingException;
078    
079      /**
080       * Advances the processing position.
081       *
082       * @param target the report target that receives generated events.
083       * @return the new layout controller instance representing the new state.
084       *
085       * @throws DataSourceException        if there was a problem reading data from
086       *                                    the datasource.
087       * @throws ReportProcessingException  if there was a general problem during
088       *                                    the report processing.
089       * @throws ReportDataFactoryException if a query failed.
090       */
091      public LayoutController advance(ReportTarget target)
092          throws DataSourceException, ReportDataFactoryException,
093          ReportProcessingException;
094    
095      /**
096       * Checks, whether the layout controller would be advanceable. If this method
097       * returns true, it is generally safe to call the 'advance()' method.
098       *
099       * @return true, if the layout controller is advanceable, false otherwise.
100       */
101      public boolean isAdvanceable();
102    
103      /**
104       * Joins with a delegated process flow. This is generally called from a child
105       * flow and should *not* (I mean it!) be called from outside. If you do,
106       * you'll suffer.
107       *
108       * @param flowController the flow controller of the parent.
109       * @return the joined layout controller that incorperates all changes from
110       * the delegate.
111       */
112      public LayoutController join(FlowController flowController)
113          throws DataSourceException, ReportDataFactoryException,
114          ReportProcessingException;
115    
116      /**
117       * Creates a copy of this layout controller.
118       *
119       * @return a copy.
120       */
121      public Object clone();
122    
123      /**
124       * Derives a copy of this controller that is suitable to perform a
125       * precomputation. The returned layout controller must be independent from
126       * the it's anchestor controller.
127       *
128       * @param fc a new flow controller for the precomputation.
129       * @return a copy that is suitable for precomputation.
130       */
131      public LayoutController createPrecomputeInstance(FlowController fc);
132    
133      public FlowController getFlowController();
134      public Object getNode();
135    }