001 package net.sf.cpsolver.ifs.multi;
002
003 import java.util.Enumeration;
004 import java.util.Vector;
005
006 import net.sf.cpsolver.ifs.model.Value;
007 import net.sf.cpsolver.ifs.model.Variable;
008 import net.sf.cpsolver.ifs.model.VariableListener;
009
010 /**
011 * A variable containing multiple "normal" variables.
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 */
034
035 public class MultiVariable extends Variable implements VariableListener {
036 private Vector iVariables;
037 public static boolean sCacheValues = false;
038
039 /** Constructor
040 * @param variables list of "normal" variables
041 */
042 public MultiVariable(Vector variables) {
043 super();
044 iVariables = variables;
045 setValues(null);
046 }
047 public MultiVariable() {
048 this(new Vector());
049 }
050
051 /** Add "normal" variable */
052 public void addVariable(Variable variable) { variables().add(variable); setValues(null); }
053 /** Remove "normal" variable */
054 public void removeVariable(Variable variable) { variables().remove(variable); setValues(null); }
055 /** List of "normal" variables */
056 public Vector variables() { return iVariables; }
057 /** Number of "normal" variables */
058 public int size() { return variables().size(); }
059
060 private void computeValues(Vector ret, Value[] values, int idx) {
061 if (idx==ret.size()) {
062 ret.addElement(new MultiValue(this, (Value[])values.clone()));
063 return;
064 }
065 Variable var = (Variable)variables().elementAt(idx);
066 for (Enumeration e=var.values().elements();e.hasMoreElements();) {
067 Value value = (Value)e.nextElement();
068 boolean inConflict = false;
069 for (int f=0;f<idx;f++) {
070 if (values[f]!=null && !values[f].isConsistent(value)) {
071 inConflict = true; break;
072 }
073 }
074 if (inConflict) continue;
075 values[idx]=value;
076 computeValues(ret, values, idx+1);
077 values[idx]=null;
078 }
079 }
080
081 /** Variable domain -- Cartesian product of the domains of the "normal" variables */
082 public Vector computeValues() {
083 Vector values = new Vector();
084 computeValues(values, new Value[size()], 0);
085 return values;
086 }
087
088 public Vector values() {
089 if (sCacheValues) {
090 Vector ret = super.values();
091 if (ret==null) {
092 ret = computeValues();
093 setValues(ret);
094 }
095 return ret;
096 } else
097 return computeValues();
098 }
099
100 public void assign(long iteration, Value value) {
101 MultiValue m = (MultiValue)value;
102 for (int i=0;i<size();i++) {
103 Variable var = (Variable)variables().elementAt(i);
104 if (var.getAssignment()!=null) var.unassign(iteration);
105 }
106 for (int i=0;i<size();i++) {
107 Variable var = (Variable)variables().elementAt(i);
108 if (m.values()[i]!=null)
109 var.assign(iteration, m.values()[i]);
110 }
111 super.assign(iteration, m);
112 }
113
114 public void unassign(long iteration) {
115 for (Enumeration e=variables().elements();e.hasMoreElements();) {
116 Variable var = (Variable)e.nextElement();
117 if (var.getAssignment()!=null)
118 var.unassign(iteration);
119 }
120 super.unassign(iteration);
121 }
122
123 public String getName() {
124 StringBuffer sb = new StringBuffer("[");
125 for (Enumeration e=variables().elements();e.hasMoreElements();) {
126 Variable v = (Variable)e.nextElement();
127 sb.append(v==null?"null":v.getName());
128 if (e.hasMoreElements()) sb.append(",");
129 }
130 sb.append("]");
131 return sb.toString();
132 }
133
134
135 public void variableAssigned(long iteration, Value value) {}
136 public void variableUnassigned(long iteration, Value value) {
137 MultiValue mValue = (MultiValue)value.getExtra();
138 if (mValue!=null && mValue.variable().getAssignment()!=null)
139 mValue.variable().unassign(iteration);
140 }
141 public void valueRemoved(long iteration, Value value) {}
142 }