001package org.cpsolver.ifs.assignment.context; 002 003import org.cpsolver.ifs.assignment.Assignment; 004import org.cpsolver.ifs.model.Model; 005import org.cpsolver.ifs.model.Value; 006import org.cpsolver.ifs.model.Variable; 007 008/** 009 * An abstract implementation of an assignment context holding class. 010 * This works much like {@link ConstraintWithContext} or {@link VariableWithContext}, however, 011 * it is not tight to a particular class type. Instead {@link AbstractClassWithContext#getModel()} 012 * needs to be implemented. 013 * 014 * @version IFS 1.3 (Iterative Forward Search)<br> 015 * Copyright (C) 2014 Tomáš Müller<br> 016 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br> 017 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br> 018 * <br> 019 * This library is free software; you can redistribute it and/or modify 020 * it under the terms of the GNU Lesser General Public License as 021 * published by the Free Software Foundation; either version 3 of the 022 * License, or (at your option) any later version. <br> 023 * <br> 024 * This library is distributed in the hope that it will be useful, but 025 * 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. <br> 028 * <br> 029 * You should have received a copy of the GNU Lesser General Public 030 * License along with this library; if not see <a href='http://www.gnu.org/licenses'>http://www.gnu.org/licenses</a>. 031 * @param <V> Variable 032 * @param <T> Value 033 * @param <C> Assignment Context 034 **/ 035public abstract class AbstractClassWithContext<V extends Variable<V, T>, T extends Value<V, T>, C extends AssignmentContext> implements HasAssignmentContext<V, T, C>, CanHoldContext { 036 private AssignmentContextReference<V, T, C> iContextReference = null; 037 private AssignmentContext[] iContext = new AssignmentContext[CanHoldContext.sMaxSize]; 038 private C iSingleContextWhenNoModel = null; 039 040 /** 041 * Returns an assignment context associated with this object. If there is no 042 * assignment context associated with this object yet, one is created using the 043 * {@link ConstraintWithContext#createAssignmentContext(Assignment)} method. 044 * @param assignment given assignment 045 * @return assignment context associated with this object and the given assignment 046 */ 047 @Override 048 public C getContext(Assignment<V, T> assignment) { 049 if (getModel() == null) { 050 if (iSingleContextWhenNoModel == null) 051 iSingleContextWhenNoModel = createAssignmentContext(assignment); 052 return iSingleContextWhenNoModel; 053 } 054 return AssignmentContextHelper.getContext(this, assignment); 055 } 056 057 @Override 058 public synchronized AssignmentContextReference<V, T, C> getAssignmentContextReference() { 059 if (iContextReference == null) 060 iContextReference = getModel().createReference(this); 061 return iContextReference; 062 } 063 064 @Override 065 public void setAssignmentContextReference(AssignmentContextReference<V, T, C> reference) { iContextReference = reference; } 066 067 @Override 068 public AssignmentContext[] getContext() { return iContext; } 069 070 /** 071 * Get the model. This is used to create an assignment context if needed. 072 * @return model 073 */ 074 public abstract Model<V,T> getModel(); 075}