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1   /*
2    *   Magic-Project is a turn based strategy simulator
3    *   Copyright (C) 2003-2007 Fabrice Daugan
4    *
5    *   This program is free software; you can redistribute it and/or modify it 
6    * under the terms of the GNU General Public License as published by the Free 
7    * Software Foundation; either version 2 of the License, or (at your option) any
8    * later version.
9    *
10   *   This program is distributed in the hope that it will be useful, but WITHOUT 
11   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
12   * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more 
13   * details.
14   *
15   *   You should have received a copy of the GNU General Public License along  
16   * with this program; if not, write to the Free Software Foundation, Inc., 
17   * 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18   * 
19   */
20  package net.sf.magicproject.operation;
21  
22  import java.io.IOException;
23  import java.io.InputStream;
24  
25  import net.sf.magicproject.expression.Expression;
26  
27  
28  /***
29   * Reprsent an operation.
30   * 
31   * @author <a href="mailto:fabdouglas@users.sourceforge.net">Fabrice Daugan </a>
32   */
33  public abstract class Operation {
34  
35  	/***
36  	 * Creates a new instance of Operation <br>
37  	 */
38  	protected Operation() {
39  		super();
40  	}
41  
42  	/***
43  	 * return the next Expression read from the current offset
44  	 * 
45  	 * @param inputFile
46  	 *          is the file containing this expression
47  	 * @return the next Expression read from the current offset
48  	 * @throws IOException
49  	 *           if error occured during the reading process from the specified
50  	 *           input stream
51  	 */
52  	public abstract Expression readNextExpression(InputStream inputFile)
53  			throws IOException;
54  
55  	/***
56  	 * Process a binary operation with two values and return the result.
57  	 * 
58  	 * @param leftValue
59  	 *          the left value of binary operation
60  	 * @param rightValue
61  	 *          the right value of binary operation
62  	 * @return the result
63  	 */
64  	public abstract int process(int leftValue, int rightValue);
65  
66  	/***
67  	 * Return operator name
68  	 * 
69  	 * @return the operator name
70  	 */
71  	public abstract String getOperator();
72  
73  	/***
74  	 * Is this operation is useless or not
75  	 * 
76  	 * @param leftValue
77  	 *          the left value
78  	 * @param rightValue
79  	 *          the right value
80  	 * @return true if this operation will not modify the given left value
81  	 *         considering the right value.
82  	 */
83  	public boolean isUselessWith(int leftValue, int rightValue) {
84  		return leftValue == process(leftValue, rightValue);
85  	}
86  }