001 /*
002 * Copyright (c) 2005 Einar Pehrson <einar@pehrson.nu>.
003 *
004 * This file is part of
005 * CleanSheets - a spreadsheet application for the Java platform.
006 *
007 * CleanSheets is free software; you can redistribute it and/or modify
008 * it under the terms of the GNU General Public License as published by
009 * the Free Software Foundation; either version 2 of the License, or
010 * (at your option) any later version.
011 *
012 * CleanSheets is distributed in the hope that it will be useful,
013 * but WITHOUT ANY WARRANTY; without even the implied warranty of
014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
015 * GNU General Public License for more details.
016 *
017 * You should have received a copy of the GNU General Public License
018 * along with CleanSheets; if not, write to the Free Software
019 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
020 */
021 package csheets.core;
022
023 import java.io.Serializable;
024 import java.util.SortedSet;
025
026 import csheets.core.formula.Formula;
027 import csheets.core.formula.compiler.FormulaCompilationException;
028 import csheets.ext.Extensible;
029
030 /**
031 * A cell in a spreadsheet.
032 * <p>The cell has content, which can be interpreted in
033 * different ways: <ul>
034 * <li>As a formula - The content should consitute a syntactically correct
035 * expression, and begin with an assignment.
036 * <li>As a value - If the cell contains a formula, the formula is evaluated to
037 * produce a value, provided that the cell does not contain calculation errors
038 * (e.g. division by 0). Otherwise, the content is interpreted as the value.
039 * </ul>
040 * @author Einar Pehrson
041 */
042 public interface Cell extends Comparable<Cell>, Extensible<Cell>, Serializable {
043
044 /*
045 * LOCATION
046 */
047
048 /**
049 * Returns the spreadsheet to which the cell belongs.
050 * @return the spreadsheet to which the cell belongs
051 */
052 public Spreadsheet getSpreadsheet();
053
054 /**
055 * Returns the address of the cell.
056 * @return the address of the cell
057 */
058 public Address getAddress();
059
060 /*
061 * VALUE
062 */
063
064 /**
065 * Returns the value of the cell.
066 * @return the value of the cell
067 */
068 public Value getValue();
069
070 /*
071 * CONTENT
072 */
073
074 /**
075 * Returns the content of the cell, as entered by the user.
076 * @return the content of the cell
077 */
078 public String getContent();
079
080 /**
081 * Returns an expression representing the cell's formula.
082 * @return the cell's formula, or null if the cell does not contain one
083 */
084 public Formula getFormula();
085
086 /**
087 * Sets the content of the cell and if it starts with the assignment operator
088 * attempts to parse a formula from it.
089 * @throws FormulaCompilationException if an incorrectly formatted formula was entered
090 */
091 public void setContent(String content) throws FormulaCompilationException;
092
093 /**
094 * Clears the content of the cell.
095 */
096 public void clear();
097
098 /*
099 * DEPENDENCIES
100 */
101
102 /**
103 * Returns the precedents of the cell, i.e. the cells that the
104 * formula in the cell references.
105 * @return a set of the cell's precedents
106 */
107 public SortedSet<Cell> getPrecedents();
108
109 /**
110 * Returns the dependents of the cell, i.e. the cells that contain a reference
111 * to the cell in their formula.
112 * @return a set of the cells which depend on the cell
113 */
114 public SortedSet<Cell> getDependents() ;
115
116 /*
117 * CLIPBOARD
118 */
119
120 /**
121 * Copies all data from the source cell to this one.
122 * @param source the cell from which data should be copied
123 */
124 public void copyFrom(Cell source);
125
126 /**
127 * Moves all data from the source cell to this one.
128 * @param source the cell from which data should be moved
129 */
130 public void moveFrom(Cell source);
131
132 /*
133 * EVENT HANDLING
134 */
135
136 /**
137 * Registers the given listener on the cell.
138 * @param listener the listener to be added
139 */
140 public void addCellListener(CellListener listener);
141
142 /**
143 * Removes the given listener from the cell.
144 * @param listener the listener to be removed
145 */
146 public void removeCellListener(CellListener listener);
147
148 /**
149 * Returns the listeners that have been registered on the cell.
150 * @return the listeners that have been registered on the cell
151 */
152 public CellListener[] getCellListeners();
153 }