Minor cleanup in CSP package.

aima-core/src/main/java/aima/core/search/csp/Assignment.java

@@ -1,7 +1,6 @@
 package aima.core.search.csp;
 
 import java.util.*;
-import java.util.stream.Collectors;
 
 /**
  * An assignment assigns values to some or all variables of a CSP.
@@ -15,7 +14,7 @@ public class Assignment<VAR extends Variable, VAL> implements Cloneable {
     private LinkedHashMap<VAR, VAL> variableToValueMap = new LinkedHashMap<>();
 
     public List<VAR> getVariables() {
-        return variableToValueMap.keySet().stream().collect(Collectors.toList());
+        return new ArrayList<>(variableToValueMap.keySet());
     }
 
     public VAL getValue(VAR var) {
@@ -40,21 +39,15 @@ public boolean contains(VAR var) {
      * <code>constraints</code>.
      */
     public boolean isConsistent(List<Constraint<VAR, VAL>> constraints) {
-        for (Constraint<VAR, VAL> cons : constraints)
-            if (!cons.isSatisfiedWith(this))
-                return false;
-        return true;
+        return constraints.stream().allMatch(cons -> cons.isSatisfiedWith(this));
     }
 
     /**
      * Returns true if this assignment assigns values to every variable of
      * <code>vars</code>.
      */
     public boolean isComplete(List<VAR> vars) {
-        for (VAR var : vars)
-            if (!contains(var))
-                return false;
-        return true;
+        return vars.stream().allMatch(this::contains);
     }
 
     /**

aima-core/src/main/java/aima/core/search/csp/CSP.java

@@ -154,8 +154,7 @@ public CSP<VAR, VAL> copyDomains() {
         CSP<VAR, VAL> result;
         try {
             result = (CSP<VAR, VAL>) clone();
-            result.domains = new ArrayList<>(domains.size());
-            result.domains.addAll(domains);
+            result.domains = new ArrayList<>(domains);
         } catch (CloneNotSupportedException e) {
             throw new UnsupportedOperationException("Could not copy domains.");
         }

aima-core/src/main/java/aima/core/search/csp/CspSolver.java

@@ -51,7 +51,6 @@ public void removeCspListener(CspListener<VAR, VAL> listener) {
 
     /** Informs all registered listeners about a state change. */
     protected void fireStateChanged(CSP<VAR, VAL> csp, Assignment<VAR, VAL> assignment, VAR variable) {
-        for (CspListener<VAR, VAL> listener : listeners)
-            listener.stateChanged(csp, assignment, variable);
+        listeners.forEach(listener -> listener.stateChanged(csp, assignment, variable));
     }
 }

aima-core/src/main/java/aima/core/search/csp/MinConflictsSolver.java

@@ -79,8 +79,7 @@ private Assignment<VAR, VAL> generateRandomAssignment(CSP<VAR, VAL> csp) {
 	private Set<VAR> getConflictedVariables(Assignment<VAR, VAL> assignment, CSP<VAR, VAL> csp) {
 		Set<VAR> result = new LinkedHashSet<>();
 		csp.getConstraints().stream().filter(constraint -> !constraint.isSatisfiedWith(assignment)).
-				forEach(constraint -> constraint.getScope().stream().filter(var -> !result.contains(var)).
-						forEach(result::add));
+				map(Constraint::getScope).forEach(result::addAll);
 		return result;
 	}
 

aima-core/src/main/java/aima/core/search/csp/Variable.java

@@ -23,7 +23,7 @@ public String toString() {
     /** Variables with equal names are equal. */
     @Override
     public final boolean equals(Object obj) {
-        return obj instanceof Variable && this.name.equals(((Variable) obj).name);
+        return (obj != null && obj.getClass() == getClass()) && name.equals(((Variable) obj).name);
     }
 
     @Override

aima-core/src/main/java/aima/core/search/csp/examples/NotEqualConstraint.java

@@ -33,7 +33,7 @@ public List<VAR> getScope() {
 
 	@Override
 	public boolean isSatisfiedWith(Assignment<VAR, VAL> assignment) {
-		Object value1 = assignment.getValue(var1);
+		VAL value1 = assignment.getValue(var1);
 		return value1 == null || !value1.equals(assignment.getValue(var2));
 	}
 }