org.metacsp.framework.Constraint Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of meta-csp-framework Show documentation
Show all versions of meta-csp-framework Show documentation
A Java API for Meta-CSP based reasoning
/*******************************************************************************
* Copyright (c) 2010-2013 Federico Pecora
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
******************************************************************************/
package org.metacsp.framework;
import java.awt.Color;
import java.awt.Paint;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.util.HashSet;
import java.util.logging.Logger;
import org.metacsp.utility.logging.MetaCSPLogging;
/**
* This class is used to represent n-ary constraints in the MetaCSP framework.
* The scope of a constraint is the set of all {@link Variable}s involved in the constraint.
* An important subclass is {@link BinaryConstraint}, which provides support for constraints
* whose scope has size two.
*
* @author Federico Pecora
*
*/
public abstract class Constraint implements Cloneable, Serializable {
private static final long serialVersionUID = 8278654163054138810L;
private HashSet solversToSkip = null;
/**
* Progressive ID of a constraint
*/
public static int numIDs = 0;
protected boolean masked = false;
protected int id;
protected Variable[] scope;
protected Object annotation;
protected boolean autoRemovable = false;
protected Paint color= Color.black;
protected transient Logger logger = MetaCSPLogging.getLogger(this.getClass());
/**
* Provide a list of solvers that should not process this constraint.
* @param solvers Solvers that should not process this constraint.
*/
public void skipSolver(ConstraintSolver ... solvers) {
if (solversToSkip == null) solversToSkip = new HashSet();
for (ConstraintSolver solver : solvers) solversToSkip.add(solver);
}
/**
* Returns true iff this {@link Constraint} is invisible to the solver (masked).
* @return true iff this {@link Constraint} is invisible to the solver (masked).
*/
public boolean isMasked() { return masked; }
/**
* Makes this {@link Constraint} invisible to the solver (masked).
*/
public void mask() { this.masked = true; }
/**
* Makes this {@link Constraint} invisible to the solver (masked).
*/
public void unmask() { this.masked = false; }
/**
* Returns true iff this {@link Constraint}'s scope only refers to one {@link Variable}.
* @return true iff this {@link Constraint}'s scope only refers to one {@link Variable}.
*/
public boolean isUnary() {
Variable oneVar = this.scope[0];
for (int i = 1; i < this.scope.length; i++) {
if (!this.scope[i].equals(oneVar)) return false;
}
return true;
}
/**
* Assess whether a given solver is allowed to process this constraint.
* @param cs The {@link ConstraintSolver} to check.
* @return true iff the given solver will process this constraint.
*/
public boolean isSkippableSolver(ConstraintSolver cs) {
return solversToSkip != null && solversToSkip.contains(cs);
}
/**
* Get this {@link Constraint}'s annotation (can be any {@link Object} and used in any way).
* @return This {@link Constraint}'s annotation.
*/
public Object getAnnotation() { return annotation; }
/**
* Set this {@link Constraint}'s annotation (can be any {@link Object} and used in any way).
* @param o This {@link Constraint}'s annotation.
*/
public void setAnnotation(Object o) { annotation = o; }
/**
* Returns the ID of this {@link Constraint}.
* @return The ID of this {@link Constraint}.
*/
public int getID() {return this.id;}
/**
* Every {@link Constraint} should implement a toString method (used by the
* {@link ConstraintNetwork} rendering methods).
* @return the {@link String} representation of this {@link Constraint}.
*/
public abstract String toString();
/**
* Every {@link Constraint} should implement this method - its value is
* what is drawn by the {@link ConstraintNetwork} rendering methods.
* @return a {@link String} representation of the constraint to be used for
* {@link ConstraintNetwork} rendering.
*/
public abstract String getEdgeLabel();
/**
* Returns the scope of this {@link Constraint}.
* @return the scope of this {@link Constraint} (an array of size 2 if this is a
* {@link BinaryConstraint}).
*/
public Variable[] getScope() {
return scope;
}
/**
* Set the scope of this {@link Constraint} to a given array of {@link Variable}s.
* @param scope The desired new scope of this {@link Constraint}.
*/
public void setScope(Variable[] scope) {
this.scope = scope;
}
@Override
public abstract Object clone();
/**
* Method for assessing the "equivalence" between two constraints. This is not used
* for lookups nor comparisons (hence, it is not the equals method).
* @param c The {@link Constraint} to compare against.
* @return true iff the two constraints are considered to be equivalent.
*/
public abstract boolean isEquivalent(Constraint c);
/**
* Get the description of this {@link Constraint}'s type.
* @return The description of this {@link Constraint}'s type.
*/
public String getDescription() {
return this.getClass().getSimpleName();
}
public boolean isAutoRemovable() {
return autoRemovable;
}
public void setAutoRemovable(boolean autoRemovable) {
this.autoRemovable = autoRemovable;
}
public Paint getColor() {
return color;
}
public void setColor(Paint color) {
this.color = color;
}
private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
in.defaultReadObject();
logger = MetaCSPLogging.getLogger(this.getClass());
}
}