001 package net.sf.cpsolver.ifs.example.jobshop;
002
003 import java.util.*;
004
005 import net.sf.cpsolver.ifs.model.*;
006
007 /**
008 * Machine constraint.
009 * <br><br>
010 * Each machine contians a given set of operations (variables).
011 * A machine constraint is satisfied, if all operations on it do not overlap in time.
012 *
013 * @version
014 * IFS 1.1 (Iterative Forward Search)<br>
015 * Copyright (C) 2006 Tomáš Müller<br>
016 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
017 * Lazenska 391, 76314 Zlin, Czech Republic<br>
018 * <br>
019 * This library is free software; you can redistribute it and/or
020 * modify it under the terms of the GNU Lesser General Public
021 * License as published by the Free Software Foundation; either
022 * version 2.1 of the License, or (at your option) any later version.
023 * <br><br>
024 * This library is distributed in the hope that it will be useful,
025 * but WITHOUT ANY WARRANTY; without even the implied warranty of
026 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
027 * Lesser General Public License for more details.
028 * <br><br>
029 * You should have received a copy of the GNU Lesser General Public
030 * License along with this library; if not, write to the Free Software
031 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
032 */
033 public class Machine extends Constraint {
034 private int iMachineNumber = -1;
035
036 /**
037 * Constructor
038 * @param machineNumber machine number
039 */
040 public Machine(int machineNumber) {
041 super();
042 iMachineNumber = machineNumber;
043 }
044
045 /** Get machine number */
046 public int getMachineNumber() { return iMachineNumber; }
047
048
049 /**
050 * Adds conflicting operations into the set of conflicts.
051 */
052 public void computeConflicts(Value value, java.util.Set conflicts) {
053 Location location = (Location)value;
054 Operation operation = (Operation)value.variable();
055 for (Enumeration e=assignedVariables().elements();e.hasMoreElements();) {
056 Operation o = (Operation)e.nextElement();
057 if (o.getOperationNumber()==operation.getOperationNumber() && o.getJobNumber()==operation.getJobNumber()) continue;
058 Location l = (Location)o.getAssignment();
059 if (l.overlap(location)) conflicts.add(l);
060 }
061 }
062
063 /**
064 * True if there is an operation from the machine which violates with the given assignment.
065 */
066 public boolean inConflict(Value value) {
067 Location location = (Location)value;
068 Operation operation = (Operation)value.variable();
069 for (Enumeration e=assignedVariables().elements();e.hasMoreElements();) {
070 Operation o = (Operation)e.nextElement();
071 if (o.getOperationNumber()==operation.getOperationNumber() && o.getJobNumber()==operation.getJobNumber()) continue;
072 Location l = (Location)o.getAssignment();
073 if (l.overlap(location)) return true;
074 }
075 return false;
076 }
077
078 /**
079 * True if the two assignments (placement of opeartions of the machine in time) violates each other.
080 */
081 public boolean isConsistent(Value value1, Value value2) {
082 return !((Location)value1).overlap((Location)value2);
083 }
084
085 /** string representation -- for debuging and printing purposes */
086 public String toString() { return getName(); }
087
088 /**
089 * Name of the machine (e.g. M10 where 10 is the machine number)
090 */
091 public String getName() { return "M"+iMachineNumber; }
092 }