refacto: dry up the static and median default grade tallies

src/main/java/fr/mieuxvoter/mj/MedianDefaultTally.java

@@ -3,7 +3,7 @@ package fr.mieuxvoter.mj;
 import java.math.BigInteger;
 
 /**
- * Fill the missing judgments into the median grade.
+ * Fill the missing judgments into the median grade of each proposal.
  * Useful when the proposals have not received the exact same amount of votes and
  * the median grade is considered a sane default.
  */

src/main/java/fr/mieuxvoter/mj/TallyWithDefaultGrade.java

@@ -2,10 +2,28 @@ package fr.mieuxvoter.mj;
 
 import java.math.BigInteger;
 
-public class TallyWithDefaultGrade extends Tally implements TallyInterface {
-
+public class TallyWithDefaultGrade extends DefaultGradeTally implements TallyInterface {
+
+	/**
+	 * Grades are represented as numbers, as indices in a list.
+	 * Grades start from 0 ("worst" grade, most conservative) and go upwards.
+	 * Values out of the range of grades defined in the tally will yield errors.
+	 * 
+	 * Example:
+	 * 
+	 *     0 == REJECT
+	 *     1 == PASSABLE
+	 *     2 == GOOD
+	 *     3 == EXCELLENT
+	 */
 	protected Integer defaultGrade = 0;
 
+	public TallyWithDefaultGrade(TallyInterface tally, Integer defaultGrade) {
+		super(tally.getProposalsTallies(), tally.getAmountOfJudges());
+		this.defaultGrade = defaultGrade;
+		fillWithDefaultGrade();
+	}
+	
 	public TallyWithDefaultGrade(ProposalTallyInterface[] proposalsTallies, BigInteger amountOfJudges, Integer defaultGrade) {
 		super(proposalsTallies, amountOfJudges);
 		this.defaultGrade = defaultGrade;
@@ -24,18 +42,9 @@ public class TallyWithDefaultGrade extends Tally implements TallyInterface {
 		fillWithDefaultGrade();
 	}
 
-	protected void fillWithDefaultGrade() {
-		int amountOfProposals = getAmountOfProposals();
-		for (int i = 0 ; i < amountOfProposals ; i++) {
-			ProposalTallyInterface proposal = getProposalsTallies()[i];
-			BigInteger amountOfJudgments = proposal.getAmountOfJudgments();
-			BigInteger missingAmount = this.amountOfJudges.subtract(amountOfJudgments);
-			int missingSign = missingAmount.compareTo(BigInteger.ZERO);
-			assert(0 <= missingSign);  // ERROR: More judgments than judges!
-			if (0 < missingSign) {
-				proposal.getTally()[this.defaultGrade] = proposal.getTally()[this.defaultGrade].add(missingAmount); 
-			}
-		}
+	@Override
+	protected Integer getDefaultGrade(ProposalTallyInterface proposalTally) {
+		return this.defaultGrade;
 	}
 
 }