001package org.cpsolver.ifs.assignment; 002 003import java.util.Collection; 004import java.util.HashMap; 005import java.util.HashSet; 006import java.util.LinkedHashMap; 007import java.util.Map; 008import java.util.Set; 009 010import org.cpsolver.ifs.assignment.context.AssignmentContextHolderMap; 011import org.cpsolver.ifs.model.Value; 012import org.cpsolver.ifs.model.Variable; 013 014 015/** 016 * An assignment inherited from some other assignment with only a few local 017 * modifications. This can be used to pass a "copy" of an assignment to a neighbour 018 * selection. 019 * 020 * @see Assignment 021 * 022 * @version IFS 1.3 (Iterative Forward Search)<br> 023 * Copyright (C) 2014 Tomas Muller<br> 024 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br> 025 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br> 026 * <br> 027 * This library is free software; you can redistribute it and/or modify 028 * it under the terms of the GNU Lesser General Public License as 029 * published by the Free Software Foundation; either version 3 of the 030 * License, or (at your option) any later version. <br> 031 * <br> 032 * This library is distributed in the hope that it will be useful, but 033 * WITHOUT ANY WARRANTY; without even the implied warranty of 034 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 035 * Lesser General Public License for more details. <br> 036 * <br> 037 * You should have received a copy of the GNU Lesser General Public 038 * License along with this library; if not see <a href='http://www.gnu.org/licenses'>http://www.gnu.org/licenses</a>. 039 * @param <V> Variable 040 * @param <T> Value 041 **/ 042public class InheritedAssignment<V extends Variable<V, T>, T extends Value<V, T>> extends AssignmentAbstract<V, T> { 043 private Assignment<V, T> iParent; 044 private Map<V, T> iAssignments = new LinkedHashMap<V, T>(); 045 private Set<V> iDirty = new HashSet<V>(); 046 private Map<V, Long> iIteration = new HashMap<V, Long>(); 047 048 public InheritedAssignment(Assignment<V, T> parent) { 049 super(new AssignmentContextHolderMap<V, T>()); 050 iParent = parent; 051 } 052 053 @Override 054 public long getIteration(V variable) { 055 Long it = iIteration.get(variable); 056 return (it != null ? it : iDirty.contains(variable) ? 0 : iParent.getIteration(variable)); 057 } 058 059 @Override 060 public Collection<V> assignedVariables() { 061 Set<V> variables = new HashSet<V>(iParent.assignedVariables()); 062 variables.removeAll(iDirty); 063 variables.addAll(iAssignments.keySet()); 064 return variables; 065 } 066 067 @Override 068 public Collection<T> assignedValues() { 069 Set<T> values = new HashSet<T>(); 070 for (T val: iParent.assignedValues()) { 071 if (!iDirty.contains(val.variable())) 072 values.add(val); 073 } 074 values.addAll(iAssignments.values()); 075 return values; 076 } 077 078 @Override 079 public int nrAssignedVariables() { 080 return iAssignments.size() + iParent.nrAssignedVariables() - iDirty.size(); 081 } 082 083 @Override 084 protected T getValueInternal(V variable) { 085 T value = iAssignments.get(variable); 086 return (value != null ? value : iDirty.contains(variable) ? null : iParent.getValue(variable)); 087 } 088 089 @Override 090 protected void setValueInternal(long iteration, V variable, T value) { 091 if (value == null) { 092 iAssignments.remove(variable); 093 iIteration.remove(variable); 094 if (iParent.getValue(variable) != null) 095 iDirty.add(variable); 096 } else { 097 iAssignments.put(variable, value); 098 if (iteration > 0) 099 iIteration.put(variable, iteration); 100 iDirty.remove(variable); 101 } 102 } 103}