1 package com.github.javaparser.symbolsolver.resolution.typeinference; 2 3 import com.github.javaparser.symbolsolver.model.resolution.TypeSolver; 4 5 import java.util.LinkedList; 6 import java.util.List; 7 8 /** 9 * @author Federico Tomassetti 10 */ 11 public class ConstraintFormulaSet { 12 private List<ConstraintFormula> constraintFormulas; 13 14 public ConstraintFormulaSet withConstraint(ConstraintFormula constraintFormula) { 15 ConstraintFormulaSet newInstance = new ConstraintFormulaSet(); 16 newInstance.constraintFormulas.addAll(this.constraintFormulas); 17 newInstance.constraintFormulas.add(constraintFormula); 18 return newInstance; 19 } 20 21 private static final ConstraintFormulaSet EMPTY = new ConstraintFormulaSet(); 22 23 public static ConstraintFormulaSet empty() { 24 return EMPTY; 25 } 26 27 private ConstraintFormulaSet() { 28 constraintFormulas = new LinkedList<>(); 29 } 30 31 /** 32 * Takes a compatibility assertion about an expression or type, called a constraint formula, and reduces it to a 33 * set of bounds on inference variables. Often, a constraint formula reduces to other constraint formulas, 34 * which must be recursively reduced. A procedure is followed to identify these additional constraint formulas and, 35 * ultimately, to express via a bound set the conditions under which the choices for inferred types would render 36 * each constraint formula true. 37 */ 38 public BoundSet reduce(TypeSolver typeSolver) { 39 List<ConstraintFormula> constraints = new LinkedList<>(constraintFormulas); 40 BoundSet boundSet = BoundSet.empty(); 41 while (constraints.size() > 0) { 42 ConstraintFormula constraintFormula = constraints.remove(0); 43 ConstraintFormula.ReductionResult reductionResult = constraintFormula.reduce(boundSet); 44 constraints.addAll(reductionResult.getConstraintFormulas()); 45 boundSet.incorporate(reductionResult.getBoundSet(), typeSolver); 46 } 47 return boundSet; 48 } 49 50 public boolean isEmpty() { 51 return constraintFormulas.isEmpty(); 52 } 53 } 54
