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authorJannis Harder <harder@informatik.uni-luebeck.de>2011-06-13 22:19:31 +0200
committerJannis Harder <harder@informatik.uni-luebeck.de>2011-06-13 22:19:31 +0200
commit2b4ad89e72fdf9612854b27bc8dd818c8f062d35 (patch)
treecf323935dd3e58f43cdd4b2c19660055639948e0 /src/jrummikub/ai
parenta15626ac3b86d3153e32b7b160403c9ab66b1034 (diff)
downloadJRummikub-2b4ad89e72fdf9612854b27bc8dd818c8f062d35.tar
JRummikub-2b4ad89e72fdf9612854b27bc8dd818c8f062d35.zip
Restructured fdsolver api and made first test succeed
git-svn-id: svn://sunsvr01.isp.uni-luebeck.de/swproj13/trunk@423 72836036-5685-4462-b002-a69064685172
Diffstat (limited to 'src/jrummikub/ai')
-rw-r--r--src/jrummikub/ai/fdsolver/Constraint.java8
-rw-r--r--src/jrummikub/ai/fdsolver/Constraints.java13
-rw-r--r--src/jrummikub/ai/fdsolver/LessThan.java9
-rw-r--r--src/jrummikub/ai/fdsolver/Propagator.java9
-rw-r--r--src/jrummikub/ai/fdsolver/Satisfiability.java5
-rw-r--r--src/jrummikub/ai/fdsolver/Solver.java192
-rw-r--r--src/jrummikub/ai/fdsolver/SolverMain.java42
-rw-r--r--src/jrummikub/ai/fdsolver/Var.java69
-rw-r--r--src/jrummikub/ai/fdsolver/constraint/ComparatorConstraint.java67
-rw-r--r--src/jrummikub/ai/fdsolver/constraint/ComparatorPropagator.java42
-rw-r--r--src/jrummikub/ai/fdsolver/constraint/Filter.java5
-rw-r--r--src/jrummikub/ai/fdsolver/constraint/FilterConstraint.java65
-rw-r--r--src/jrummikub/ai/fdsolver/constraint/FilterPropagator.java31
-rw-r--r--src/jrummikub/ai/fdsolver/constraint/GreaterThan.java18
-rw-r--r--src/jrummikub/ai/fdsolver/constraint/GreaterThanConst.java15
-rw-r--r--src/jrummikub/ai/fdsolver/constraint/LessThan.java17
-rw-r--r--src/jrummikub/ai/fdsolver/constraint/LessThanConst.java18
17 files changed, 583 insertions, 42 deletions
diff --git a/src/jrummikub/ai/fdsolver/Constraint.java b/src/jrummikub/ai/fdsolver/Constraint.java
index 0d4071d..f7955ce 100644
--- a/src/jrummikub/ai/fdsolver/Constraint.java
+++ b/src/jrummikub/ai/fdsolver/Constraint.java
@@ -1,5 +1,11 @@
package jrummikub.ai.fdsolver;
+import java.util.Collection;
+
public interface Constraint {
-
+ public Collection<Var<?>> getWatchedVars();
+
+ public Collection<Propagator> getPropagators(boolean negate);
+
+ public Satisfiability getSatisfiability();
}
diff --git a/src/jrummikub/ai/fdsolver/Constraints.java b/src/jrummikub/ai/fdsolver/Constraints.java
deleted file mode 100644
index 589ecb5..0000000
--- a/src/jrummikub/ai/fdsolver/Constraints.java
+++ /dev/null
@@ -1,13 +0,0 @@
-package jrummikub.ai.fdsolver;
-
-public class Constraints {
-
- public static <T extends Comparable<T>> void lessThan(Solver solver, Var<T> x, Var<T> y) {
- // TODO Auto-generated method stub
- }
-
- public static <T extends Comparable<T>> void lessThan(Solver solver, Var<T> x, T y) {
- // TODO Auto-generated method stub
- }
-
-}
diff --git a/src/jrummikub/ai/fdsolver/LessThan.java b/src/jrummikub/ai/fdsolver/LessThan.java
deleted file mode 100644
index 25acd9b..0000000
--- a/src/jrummikub/ai/fdsolver/LessThan.java
+++ /dev/null
@@ -1,9 +0,0 @@
-package jrummikub.ai.fdsolver;
-
-public class LessThan<T> implements Constraint {
-
- public LessThan(Var<T> x, Var<T> y) {
- // TODO Auto-generated constructor stub
- }
-
-}
diff --git a/src/jrummikub/ai/fdsolver/Propagator.java b/src/jrummikub/ai/fdsolver/Propagator.java
new file mode 100644
index 0000000..dfe720a
--- /dev/null
+++ b/src/jrummikub/ai/fdsolver/Propagator.java
@@ -0,0 +1,9 @@
+package jrummikub.ai.fdsolver;
+
+import java.util.Collection;
+
+public interface Propagator {
+ public abstract Collection<Var<?>> getWatchedVars();
+
+ public abstract void propagate();
+}
diff --git a/src/jrummikub/ai/fdsolver/Satisfiability.java b/src/jrummikub/ai/fdsolver/Satisfiability.java
new file mode 100644
index 0000000..9f3a23a
--- /dev/null
+++ b/src/jrummikub/ai/fdsolver/Satisfiability.java
@@ -0,0 +1,5 @@
+package jrummikub.ai.fdsolver;
+
+public enum Satisfiability {
+ TAUT, SAT, UNSAT
+}
diff --git a/src/jrummikub/ai/fdsolver/Solver.java b/src/jrummikub/ai/fdsolver/Solver.java
index 1164c36..6660467 100644
--- a/src/jrummikub/ai/fdsolver/Solver.java
+++ b/src/jrummikub/ai/fdsolver/Solver.java
@@ -1,25 +1,195 @@
package jrummikub.ai.fdsolver;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+
public class Solver {
+ Set<Var<?>> vars = new HashSet<Var<?>>();
+
+ Set<Var<?>> dirtyVars = new HashSet<Var<?>>();
+
+ Set<Var<?>> unsolvedVars = new HashSet<Var<?>>();
+
+ Set<Constraint> constraints = new HashSet<Constraint>();
+
+ ArrayList<StackFrame> stack = new ArrayList<StackFrame>();
+
+ boolean contradiction = false;
- public void add(Constraint constraint) {
- // TODO Auto-generated method stub
-
+ static private class StackFrame {
+ Map<Var<?>, HashSet<?>> invalidatedValues = new HashMap<Var<?>, HashSet<?>>();
+ Var<?> branchVar;
+ Object branchValue;
+
+ public <T> void invalidate(Var<T> var, T invalid) {
+ HashSet<T> values = (HashSet<T>) invalidatedValues.get(var);
+ if (values == null) {
+ invalidatedValues.put(var,
+ new HashSet<T>(Arrays.asList(invalid)));
+ } else {
+ values.add(invalid);
+ }
+ }
+
+ @Override
+ public String toString() {
+ return "StackItem [invalidatedValues=" + invalidatedValues + "]";
+ }
+ }
+
+ public Solver() {
+ stack.add(new StackFrame());
}
public boolean solve() {
- // TODO Auto-generated method stub
- return false;
+ do {
+ solveStep();
+ } while (!(contradiction || (dirtyVars.isEmpty() && unsolvedVars
+ .isEmpty())));
+ return !contradiction;
+ }
+
+ public void solveStep() {
+ if (unsolvedVars.isEmpty() && dirtyVars.isEmpty()) {
+ contradiction = true;
+ } else {
+ propagateAll();
+ }
+ if (contradiction) {
+ if (stack.size() == 1) {
+ return;
+ }
+ backtrack();
+ } else if (unsolvedVars.isEmpty()) {
+ return;
+ } else {
+ branch();
+ }
+ }
+
+ public void propagateOnce() {
+ Iterator<Var<?>> it = dirtyVars.iterator();
+ Var<?> dirtyVar = it.next();
+ it.remove();
+ outerLoop: for (Constraint constraint : constraints) {
+ if (constraint.getWatchedVars().contains(dirtyVar)) {
+ for (Propagator propagator : constraint.getPropagators(false)) {
+ if (propagator.getWatchedVars().contains(dirtyVar)) {
+ propagator.propagate();
+ if (contradiction) {
+ break outerLoop;
+ }
+ }
+ }
+ }
+ }
+ }
+
+ public void propagateAll() {
+ while (!(dirtyVars.isEmpty() || contradiction)) {
+ propagateOnce();
+ }
+ }
+
+ public void addVar(Var<?> var) {
+ vars.add(var);
+ if (var.getRange().size() != 1) {
+ unsolvedVars.add(var);
+ }
+ }
+
+ public void addConstraint(Constraint constraint) {
+ constraints.add(constraint);
+
+ for (Var<?> var : constraint.getWatchedVars()) {
+ var.makeDirty();
+ }
+ }
+
+ // backtracking and logging
+
+ void branch() {
+ branchOn(unsolvedVars.iterator().next());
+ }
+
+ @SuppressWarnings("unchecked")
+ void branchOn(Var<?> var) {
+ Object value = var.getRange().iterator().next();
+ branchWith((Var<Object>) var, value);
+ }
+
+ <T> void branchWith(Var<T> var, T value) {
+ StackFrame stackFrame = new StackFrame();
+ stackFrame.branchVar = var;
+ stackFrame.branchValue = value;
+ stack.add(stackFrame);
+ var.choose(value);
+ }
+
+ private StackFrame getTopStackFrame() {
+ return stack.get(stack.size() - 1);
+ }
+
+ <T> void logInvalidation(Var<T> var, T invalid) {
+ getTopStackFrame().invalidate(var, invalid);
+ if (var.getRange().size() == 1) {
+ unsolvedVars.remove(var);
+ }
+ }
+
+ @SuppressWarnings("unchecked")
+ // This would need rank-2 types which java lacks
+ private void rollback(StackFrame item) {
+ for (Map.Entry<Var<?>, HashSet<?>> entry : item.invalidatedValues
+ .entrySet()) {
+ Var<Object> var = (Var<Object>) entry.getKey();
+ HashSet<Object> values = (HashSet<Object>) entry.getValue();
+ var.getRange().addAll(values);
+ if (var.getRange().size() != 1) {
+ unsolvedVars.add(var);
+ } else {
+ unsolvedVars.remove(var);
+ }
+ }
+ }
+
+ @SuppressWarnings("unchecked")
+ void backtrack() {
+ contradiction = false;
+ StackFrame topFrame = getTopStackFrame();
+ rollback(topFrame);
+ stack.remove(stack.size() - 1);
+ ((Var<Object>) topFrame.branchVar).invalidate(topFrame.branchValue);
+ }
+
+ // factory methods for vars
+
+ public Var<Integer> makeRangeVar(int low, int high) {
+ ArrayList<Integer> range = new ArrayList<Integer>();
+ for (int i = low; i <= high; i++) {
+ range.add(i);
+ }
+ return makeVar(range);
+ }
+
+ public Var<Boolean> makeBoolVar() {
+ return makeVar(true, false);
}
- public void push() {
- // TODO Auto-generated method stub
-
+ public <T> Var<T> makeVar(Collection<T> range) {
+ Var<T> var = new Var<T>(this, range);
+ addVar(var);
+ return var;
}
- public void pop() {
- // TODO Auto-generated method stub
-
+ public <T> Var<T> makeVar(T... range) {
+ return makeVar(Arrays.asList(range));
}
}
diff --git a/src/jrummikub/ai/fdsolver/SolverMain.java b/src/jrummikub/ai/fdsolver/SolverMain.java
new file mode 100644
index 0000000..4750675
--- /dev/null
+++ b/src/jrummikub/ai/fdsolver/SolverMain.java
@@ -0,0 +1,42 @@
+package jrummikub.ai.fdsolver;
+
+
+public class SolverMain {
+
+ /*
+ * eingabe: liste handsteinen + liste tischsteinen
+ *
+ * foreach stein: stein id (durchlaufend nummeriert) Var<Boolean> onTable =
+ * tisch ? {true}, {true, false} Var<Integer> value = {N} Var<StoneColor>
+ * color = {C} Var<Integer> nachbarL,R = {-1, 0...steinanzahl} Var<Boolean>
+ * groupOrRun
+ *
+ * nachbarR != -1 => nachbarL[nachbarR[id]] == id nachbarL != -1 =>
+ * nachbarR[nachbarL[id]] == id
+ *
+ * nachbarR != -1 => gOR[nachbarR[id]] = gOR nachbarL != -1 =>
+ * gOR[nachbarL[id]] = gOR
+ *
+ * nachbar{R,L} != -1 => group <=> value[{R,L}] == value nachbar{R,L} != -1
+ * && group => color[{R,L}] {<,>} color // hier auch <=> ?
+ *
+ * nachbar{R,L} != -1 => run <=> color[{R,L}] == color nachbar{R,L} != -1 =>
+ * run <=> value[{R,L}] == value {+,-} 1
+ *
+ * Var<Integer> pos von {links, rechts} + constraints
+ *
+ * links + rechts >= 3
+ *
+ * foreach handstein: Var<Integer> badness = onTable ? ### (z. B. 1) : 0
+ *
+ * totalBadness = sum(all badness)
+ *
+ * foreach joker: Var<Integer> value = {-1, 1..13} Var<StoneColor> color =
+ * {F, C0..C3} onTable == false <=> value == -1 same with color
+ *
+ * joker sind sortiert
+ */
+ public static void main(String[] args) {
+ }
+
+}
diff --git a/src/jrummikub/ai/fdsolver/Var.java b/src/jrummikub/ai/fdsolver/Var.java
index a2b5cd7..eb6f432 100644
--- a/src/jrummikub/ai/fdsolver/Var.java
+++ b/src/jrummikub/ai/fdsolver/Var.java
@@ -2,24 +2,77 @@ package jrummikub.ai.fdsolver;
import java.util.Collection;
import java.util.HashSet;
-import java.util.Set;
+import java.util.Iterator;
public class Var<T> {
- Set<T> range;
-
+ private Solver solver;
+ private HashSet<T> range;
+
public Var(Solver solver, Collection<T> range) {
+ this.solver = solver;
this.range = new HashSet<T>(range);
}
- public static <T> Var<T> range(Solver solver, T low, T high) {
- // TODO todo todo todo
- return null;
- }
-
public T getValue() {
if (range.size() != 1)
return null;
return range.iterator().next();
}
+ public HashSet<T> getRange() {
+ return range;
+ }
+
+ public void choose(T value) {
+ for (Iterator<T> i = this.iterator(); i.hasNext();) {
+ if (i.next() != value) {
+ i.remove();
+ }
+ }
+ }
+
+ public void makeDirty() {
+ this.solver.dirtyVars.add(this);
+ }
+
+ public void invalidate(T value) {
+ range.remove(value);
+ solver.logInvalidation(this, value);
+ makeDirty();
+ }
+
+ public Iterator<T> iterator() {
+ final Iterator<T> iterator = range.iterator();
+ return new Iterator<T>() {
+ T lastValue;
+
+ @Override
+ public boolean hasNext() {
+ return iterator.hasNext();
+ }
+
+ @Override
+ public T next() {
+ lastValue = iterator.next();
+ return lastValue;
+ }
+
+ @Override
+ public void remove() {
+ // TODO logging
+ iterator.remove();
+ solver.logInvalidation(Var.this, lastValue);
+ makeDirty();
+ if (range.size() == 0) {
+ solver.contradiction = true;
+ }
+ }
+ };
+ }
+
+ @Override
+ public String toString() {
+ return "Var" + range;
+ }
+
}
diff --git a/src/jrummikub/ai/fdsolver/constraint/ComparatorConstraint.java b/src/jrummikub/ai/fdsolver/constraint/ComparatorConstraint.java
new file mode 100644
index 0000000..24e7ecf
--- /dev/null
+++ b/src/jrummikub/ai/fdsolver/constraint/ComparatorConstraint.java
@@ -0,0 +1,67 @@
+package jrummikub.ai.fdsolver.constraint;
+
+import static jrummikub.ai.fdsolver.Satisfiability.*;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+
+import jrummikub.ai.fdsolver.Constraint;
+import jrummikub.ai.fdsolver.Propagator;
+import jrummikub.ai.fdsolver.Satisfiability;
+import jrummikub.ai.fdsolver.Var;
+
+public class ComparatorConstraint<T> implements Constraint {
+ Var<T> x, y;
+ Comparator<T> comparator, reverseComparator;
+ ComparatorPropagator<T> trueX, trueY, falseX, falseY;
+ boolean allowEqual;
+
+ ComparatorConstraint(final Comparator<T> comparator, boolean allowEqual, Var<T> x, Var<T> y) {
+ this.x = x;
+ this.y = y;
+ this.comparator = comparator;
+ this.allowEqual = allowEqual;
+ reverseComparator = new Comparator<T>() {
+ @Override
+ public int compare(T o1, T o2) {
+ return comparator.compare(o2, o1);
+ }
+ };
+ trueX = new ComparatorPropagator<T>(comparator, allowEqual, x, y);
+ trueY = new ComparatorPropagator<T>(reverseComparator, allowEqual, y, x);
+ falseX = new ComparatorPropagator<T>(reverseComparator, !allowEqual, x, y);
+ falseY = new ComparatorPropagator<T>(comparator, !allowEqual, y, x);
+ }
+
+ @Override
+ public Collection<Var<?>> getWatchedVars() {
+ return Arrays.<Var<?>>asList(x,y);
+ }
+
+ @Override
+ public Collection<Propagator> getPropagators(boolean negate) {
+ if (negate) {
+ return Arrays.<Propagator>asList(falseX,falseY);
+ } else {
+ return Arrays.<Propagator>asList(trueX,trueY);
+ }
+ }
+
+ @Override
+ public Satisfiability getSatisfiability() {
+ T maxX = Collections.max(x.getRange(), comparator);
+ T minY = Collections.min(y.getRange(), comparator);
+ if (comparator.compare(maxX, minY) < (allowEqual ? 1 : 0)) {
+ return TAUT;
+ }
+ T minX = Collections.min(x.getRange(), comparator);
+ T maxY = Collections.max(y.getRange(), comparator);
+ if (comparator.compare(maxY, minX) < (allowEqual ? 0 : 1)) {
+ return UNSAT;
+ }
+ return SAT;
+ }
+
+}
diff --git a/src/jrummikub/ai/fdsolver/constraint/ComparatorPropagator.java b/src/jrummikub/ai/fdsolver/constraint/ComparatorPropagator.java
new file mode 100644
index 0000000..b3a3089
--- /dev/null
+++ b/src/jrummikub/ai/fdsolver/constraint/ComparatorPropagator.java
@@ -0,0 +1,42 @@
+package jrummikub.ai.fdsolver.constraint;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+
+import jrummikub.ai.fdsolver.Propagator;
+import jrummikub.ai.fdsolver.Var;
+
+public class ComparatorPropagator<T> implements Propagator {
+ private Var<T> x, y;
+ private Comparator<T> comparator;
+ private boolean allowEqual;
+ public ComparatorPropagator(Comparator<T> comparator, boolean allowEqual, Var<T> x, Var<T> y) {
+ this.comparator = comparator;
+ this.allowEqual = allowEqual;
+ this.x = x;
+ this.y = y;
+ }
+
+ @Override
+ public Collection<Var<?>> getWatchedVars() {
+ return Arrays.<Var<?>>asList(y);
+ }
+
+ @Override
+ public void propagate() {
+ T maxY = Collections.max(y.getRange(), comparator);
+
+ for(Iterator<T> i = x.iterator(); i.hasNext();) {
+ T value = i.next();
+ int comparision = comparator.compare(value, maxY);
+ if (comparision > 0 || comparision == 0 && !allowEqual) {
+ i.remove();
+ }
+ }
+ }
+}
diff --git a/src/jrummikub/ai/fdsolver/constraint/Filter.java b/src/jrummikub/ai/fdsolver/constraint/Filter.java
new file mode 100644
index 0000000..59c880a
--- /dev/null
+++ b/src/jrummikub/ai/fdsolver/constraint/Filter.java
@@ -0,0 +1,5 @@
+package jrummikub.ai.fdsolver.constraint;
+
+public interface Filter<T> {
+ public boolean accept(T value);
+}
diff --git a/src/jrummikub/ai/fdsolver/constraint/FilterConstraint.java b/src/jrummikub/ai/fdsolver/constraint/FilterConstraint.java
new file mode 100644
index 0000000..e676882
--- /dev/null
+++ b/src/jrummikub/ai/fdsolver/constraint/FilterConstraint.java
@@ -0,0 +1,65 @@
+package jrummikub.ai.fdsolver.constraint;
+
+import static jrummikub.ai.fdsolver.Satisfiability.SAT;
+import static jrummikub.ai.fdsolver.Satisfiability.TAUT;
+import static jrummikub.ai.fdsolver.Satisfiability.UNSAT;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import jrummikub.ai.fdsolver.Constraint;
+import jrummikub.ai.fdsolver.Propagator;
+import jrummikub.ai.fdsolver.Satisfiability;
+import jrummikub.ai.fdsolver.Var;
+
+public class FilterConstraint<T> implements Constraint {
+ private Var<T> var;
+ private Propagator trueProp, falseProp;
+ private Filter<T> filter;
+
+ public FilterConstraint(final Filter<T> filter, Var<T> var) {
+ this.var = var;
+ this.filter = filter;
+ trueProp = new FilterPropagator<T>(filter, var);
+ falseProp = new FilterPropagator<T>(new Filter<T>() {
+ @Override
+ public boolean accept(T value) {
+ return !filter.accept(value);
+ }
+ }, var);
+ }
+
+ @Override
+ public Collection<Var<?>> getWatchedVars() {
+ return Arrays.<Var<?>> asList(var);
+ }
+
+ @Override
+ public Collection<Propagator> getPropagators(boolean negate) {
+ return Arrays.asList(negate ? falseProp : trueProp);
+ }
+
+ @Override
+ public Satisfiability getSatisfiability() {
+ boolean any = false;
+ boolean all = true;
+
+ for (T value : var.getRange()) {
+ boolean accepted = filter.accept(value);
+ if (accepted) {
+ any = true;
+ } else {
+ all = false;
+ }
+ }
+
+ if (all && any) {
+ return TAUT;
+ } else if (any) {
+ return SAT;
+ } else {
+ return UNSAT;
+ }
+ }
+
+}
diff --git a/src/jrummikub/ai/fdsolver/constraint/FilterPropagator.java b/src/jrummikub/ai/fdsolver/constraint/FilterPropagator.java
new file mode 100644
index 0000000..80518c9
--- /dev/null
+++ b/src/jrummikub/ai/fdsolver/constraint/FilterPropagator.java
@@ -0,0 +1,31 @@
+package jrummikub.ai.fdsolver.constraint;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Iterator;
+
+import jrummikub.ai.fdsolver.Propagator;
+import jrummikub.ai.fdsolver.Var;
+
+public class FilterPropagator<T> implements Propagator {
+ private Filter<T> filter;
+ private Var<T> var;
+
+ public FilterPropagator(Filter<T> filter, Var<T> var) {
+ this.filter = filter;
+ this.var = var;
+ }
+
+ @Override
+ public Collection<Var<?>> getWatchedVars() {
+ return Arrays.<Var<?>>asList(var);
+ }
+
+ @Override
+ public void propagate() {
+ for(Iterator<T> i = var.iterator(); i.hasNext();) {
+ if(!filter.accept(i.next()))
+ i.remove();
+ }
+ }
+}
diff --git a/src/jrummikub/ai/fdsolver/constraint/GreaterThan.java b/src/jrummikub/ai/fdsolver/constraint/GreaterThan.java
new file mode 100644
index 0000000..9bdccd2
--- /dev/null
+++ b/src/jrummikub/ai/fdsolver/constraint/GreaterThan.java
@@ -0,0 +1,18 @@
+package jrummikub.ai.fdsolver.constraint;
+
+import java.util.Comparator;
+
+import jrummikub.ai.fdsolver.Var;
+
+public class GreaterThan<T extends Comparable<T>> extends
+ ComparatorConstraint<T> {
+
+ public GreaterThan(boolean allowEqual, Var<T> x, Var<T> y) {
+ super(new Comparator<T>() {
+ @Override
+ public int compare(T o1, T o2) {
+ return o2.compareTo(o1);
+ }
+ }, allowEqual, x, y);
+ }
+}
diff --git a/src/jrummikub/ai/fdsolver/constraint/GreaterThanConst.java b/src/jrummikub/ai/fdsolver/constraint/GreaterThanConst.java
new file mode 100644
index 0000000..6b00ee3
--- /dev/null
+++ b/src/jrummikub/ai/fdsolver/constraint/GreaterThanConst.java
@@ -0,0 +1,15 @@
+package jrummikub.ai.fdsolver.constraint;
+
+import jrummikub.ai.fdsolver.Var;
+
+public class GreaterThanConst<T extends Comparable<T>> extends
+ FilterConstraint<T> {
+ public GreaterThanConst(final boolean allowEqual, Var<T> x, final T y) {
+ super(new Filter<T>() {
+ @Override
+ public boolean accept(T value) {
+ return y.compareTo(value) < (allowEqual ? 1 : 0);
+ }
+ }, x);
+ }
+}
diff --git a/src/jrummikub/ai/fdsolver/constraint/LessThan.java b/src/jrummikub/ai/fdsolver/constraint/LessThan.java
new file mode 100644
index 0000000..b79252c
--- /dev/null
+++ b/src/jrummikub/ai/fdsolver/constraint/LessThan.java
@@ -0,0 +1,17 @@
+package jrummikub.ai.fdsolver.constraint;
+
+import java.util.Comparator;
+
+import jrummikub.ai.fdsolver.Var;
+
+public class LessThan<T extends Comparable<T>> extends ComparatorConstraint<T> {
+
+ public LessThan(boolean allowEqual, Var<T> x, Var<T> y) {
+ super(new Comparator<T>() {
+ @Override
+ public int compare(T o1, T o2) {
+ return o1.compareTo(o2);
+ }
+ }, allowEqual, x, y);
+ }
+}
diff --git a/src/jrummikub/ai/fdsolver/constraint/LessThanConst.java b/src/jrummikub/ai/fdsolver/constraint/LessThanConst.java
new file mode 100644
index 0000000..18d8827
--- /dev/null
+++ b/src/jrummikub/ai/fdsolver/constraint/LessThanConst.java
@@ -0,0 +1,18 @@
+package jrummikub.ai.fdsolver.constraint;
+
+import java.util.Collection;
+
+import jrummikub.ai.fdsolver.Propagator;
+import jrummikub.ai.fdsolver.Solver;
+import jrummikub.ai.fdsolver.Var;
+
+public class LessThanConst<T extends Comparable<T>> extends FilterConstraint<T> {
+ public LessThanConst(final boolean allowEqual, Var<T> x, final T y) {
+ super(new Filter<T>() {
+ @Override
+ public boolean accept(T value) {
+ return value.compareTo(y) < (allowEqual ? 1 : 0);
+ }
+ }, x);
+ }
+}