1 files changed, 53 insertions, 0 deletions
diff --git a/javaparser-symbol-solver-core/src/main/java/com/github/javaparser/symbolsolver/resolution/typeinference/ConstraintFormulaSet.java b/javaparser-symbol-solver-core/src/main/java/com/github/javaparser/symbolsolver/resolution/typeinference/ConstraintFormulaSet.java
new file mode 100644
index 000000000..bca6e12e4
--- /dev/null
+++ b/javaparser-symbol-solver-core/src/main/java/com/github/javaparser/symbolsolver/resolution/typeinference/ConstraintFormulaSet.java
@@ -0,0 +1,53 @@
+package com.github.javaparser.symbolsolver.resolution.typeinference;
+
+import com.github.javaparser.symbolsolver.model.resolution.TypeSolver;
+
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * @author Federico Tomassetti
+ */
+public class ConstraintFormulaSet {
+    private List<ConstraintFormula> constraintFormulas;
+
+    public ConstraintFormulaSet withConstraint(ConstraintFormula constraintFormula) {
+        ConstraintFormulaSet newInstance = new ConstraintFormulaSet();
+        newInstance.constraintFormulas.addAll(this.constraintFormulas);
+        newInstance.constraintFormulas.add(constraintFormula);
+        return newInstance;
+    }
+
+    private static final ConstraintFormulaSet EMPTY = new ConstraintFormulaSet();
+
+    public static ConstraintFormulaSet empty() {
+        return EMPTY;
+    }
+
+    private ConstraintFormulaSet() {
+        constraintFormulas = new LinkedList<>();
+    }
+
+    /**
+     * Takes a compatibility assertion about an expression or type, called a constraint formula, and reduces it to a
+     * set of bounds on inference variables. Often, a constraint formula reduces to other constraint formulas,
+     * which must be recursively reduced. A procedure is followed to identify these additional constraint formulas and,
+     * ultimately, to express via a bound set the conditions under which the choices for inferred types would render
+     * each constraint formula true.
+     */
+    public BoundSet reduce(TypeSolver typeSolver) {
+        List<ConstraintFormula> constraints = new LinkedList<>(constraintFormulas);
+        BoundSet boundSet = BoundSet.empty();
+        while (constraints.size() > 0) {
+            ConstraintFormula constraintFormula = constraints.remove(0);
+            ConstraintFormula.ReductionResult reductionResult = constraintFormula.reduce(boundSet);
+            constraints.addAll(reductionResult.getConstraintFormulas());
+            boundSet.incorporate(reductionResult.getBoundSet(), typeSolver);
+        }
+        return boundSet;
+    }
+
+    public boolean isEmpty() {
+        return constraintFormulas.isEmpty();
+    }
+}