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A Java API for Meta-CSP based reasoning
package org.metacsp.multi.spatial.DE9IM;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.logging.Logger;
import org.metacsp.framework.Constraint;
import org.metacsp.framework.ConstraintNetwork;
import org.metacsp.framework.ConstraintSolver;
import org.metacsp.framework.Variable;
import org.metacsp.multi.spatial.DE9IM.DE9IMRelation.Type;
import org.metacsp.utility.logging.MetaCSPLogging;
/**
* A solver for constraint networks of {@link DE9IMRelation}s. This solver handles variables of type {@link GeometricShapeVariable}, which represent
* points, line strings, or polygons. The latter are not necessarily convex.
*
* @author Federico Pecora
*
*/
public class DE9IMRelationSolver extends ConstraintSolver {
protected Constraint[] addedConstraints = null;
protected boolean removedConstraints = false;
protected boolean addedVariables = false;
protected boolean removedVariables = false;
protected DE9IMRelationSolver(Class[] constraintTypes, Class variableType) {
super(constraintTypes, variableType);
}
/**
* Creates a new solver for {@link DE9IMRelation}s.
*/
public DE9IMRelationSolver() {
super(new Class[] {DE9IMRelation.class}, GeometricShapeVariable.class);
this.setOptions(OPTIONS.DOMAINS_AUTO_INSTANTIATED, OPTIONS.AUTO_PROPAGATE);
}
private static final long serialVersionUID = 2872228080625654304L;
/**
* Get all the implicit {@link DE9IMRelation}s that exist among the variables in this solver's {@link ConstraintNetwork}.
* @return All the implicit {@link DE9IMRelation}s that exist among the variables in this solver's {@link ConstraintNetwork}.
*/
public Constraint[] getAllImplicitRelations() {
return this.getAllImplicitRelations(false);
}
/**
* Get all the implicit {@link DE9IMRelation}s that exist among the variables in this solver's {@link ConstraintNetwork}. These
* are limited to the eight Jointly Exclusive, Pairwise Disjoint relations
*
* - Contains
* - Within
* - Covers
* - CoveredBy
* - Disjoint
* - Overlaps
* - Touches
* - Equals
*
* These eight relations are equivalent to te basic RCC8 relations (Cohn et al., 1997).
* @return All the implicit {@link DE9IMRelation}s that are also RCC8 relations existing among the variables in this solver's {@link ConstraintNetwork}.
*/
public Constraint[] getAllImplicitRCC8Relations() {
return this.getAllImplicitRelations(true);
}
private Constraint[] getAllImplicitRelations(boolean rcc8relations) {
ArrayList cons = new ArrayList();
Variable[] vars = this.getVariables();
for (int i = 0; i < vars.length; i++) {
GeometricShapeVariable g1 = (GeometricShapeVariable)vars[i];
for (int j = 0; j < vars.length; j++) {
if (i != j) {
GeometricShapeVariable g2 = (GeometricShapeVariable)vars[j];
Type[] rels = null;
if (!rcc8relations) rels = DE9IMRelation.getRelations(g1, g2);
else rels = DE9IMRelation.getRCC8Relations(g1, g2);
DE9IMRelation con = new DE9IMRelation(rels);
con.setFrom(g1);
con.setTo(g2);
cons.add(con);
}
}
}
return cons.toArray(new Constraint[cons.size()]);
}
@Override
public boolean propagate() {
if (addedConstraints != null) {
for (Constraint con : addedConstraints) {
if (con instanceof DE9IMRelation) {
if (!propagateEdge((DE9IMRelation)con)) return false;
}
}
addedConstraints = null;
return true;
}
if (removedConstraints) {
logger.fine("Propagation skipped because only removing constriants");
removedConstraints = false;
return true;
}
if (addedVariables) {
logger.fine("Propagation skipped because only adding variables");
addedVariables = false;
return true;
}
if (removedVariables) {
logger.fine("Propagation skipped because only removing variables");
removedVariables = false;
return true;
}
return propagateFull();
}
private boolean propagateEdge(DE9IMRelation con) {
logger.fine("Edge propagation performed");
GeometricShapeVariable g1 = (GeometricShapeVariable)con.getFrom();
GeometricShapeVariable g2 = (GeometricShapeVariable)con.getTo();
//Are explicit (given) relations compatible with implicit ones?
Type[] implicitRelsA = DE9IMRelation.getRelations(g1, g2);
HashSet implicitRels = new HashSet();
for (Type t : implicitRelsA) implicitRels.add(t);
for (Type t : con.getTypes()) {
//System.out.println(implicitRels + " contains " + t + "?");
if (!implicitRels.contains(t)) {
//System.out.println("... no!");
return false;
}
}
//... yes!
return true;
}
private boolean propagateFull() {
logger.fine("Full propagation performed");
Variable[] vars = this.getVariables();
for (int i = 0; i < vars.length; i++) {
GeometricShapeVariable g1 = (GeometricShapeVariable)vars[i];
for (int j = 0; j < vars.length; j++) {
if (i != j) {
GeometricShapeVariable g2 = (GeometricShapeVariable)vars[j];
//Are explicit (given) relations compatible with implicit ones?
Type[] implicitRelsA = DE9IMRelation.getRelations(g1, g2);
HashSet implicitRels = new HashSet();
for (Type t : implicitRelsA) implicitRels.add(t);
Constraint[] cons = this.getConstraints(g1, g2);
for (Constraint c : cons) {
for (Type t : ((DE9IMRelation)c).getTypes()) {
//System.out.println(implicitRels + " contains " + t + "?");
if (!implicitRels.contains(t)) {
//System.out.println("... no!");
return false;
}
}
}
//... yes!
}
}
}
return true;
}
private boolean propagateRCC8() {
Variable[] vars = this.getVariables();
for (int i = 0; i < vars.length; i++) {
GeometricShapeVariable g1 = (GeometricShapeVariable)vars[i];
for (int j = 0; j < vars.length; j++) {
if (i != j) {
GeometricShapeVariable g2 = (GeometricShapeVariable)vars[j];
//Are explicit (given, RCC8) relations compatible with implicit ones?
Type[] implicitRelsA = DE9IMRelation.getRCC8Relations(g1, g2);
HashSet implicitRels = new HashSet();
for (Type t : implicitRelsA) implicitRels.add(t);
Constraint[] cons = this.getConstraints(g1, g2);
for (Constraint c : cons) {
for (Type t : ((DE9IMRelation)c).getTypes()) {
if (!DE9IMRelation.isRCC8Relation(t)) {
//System.out.println(t + " is not RCC8, skipping...");
continue;
}
//System.out.println(implicitRels + " contains " + t + "?");
if (!implicitRels.contains(t)) {
//System.out.println("... no!");
return false;
}
}
}
//... yes!
}
}
}
return true;
}
@Override
protected boolean addConstraintsSub(Constraint[] c) {
addedConstraints = c;
return true;
}
@Override
protected void removeConstraintsSub(Constraint[] c) {
removedConstraints = true;
}
@Override
protected Variable[] createVariablesSub(int num) {
addedVariables = true;
Variable[] ret = new Variable[num];
for (int i = 0; i < num; i++) {
ret[i] = new GeometricShapeVariable(this, IDs++);
}
return ret;
}
@Override
protected void removeVariablesSub(Variable[] v) {
removedVariables = true;
}
@Override
public void registerValueChoiceFunctions() {
// TODO Auto-generated method stub
}
}