Implemented stochastic grammar. Work in progress.

src/dk/itu/mario/level/grammar/OrClause.java

@@ -0,0 +1,59 @@
+package dk.itu.mario.level.grammar;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class OrClause implements Clause {
+	private double[] chances;
+	private List<Clause> subClauses = new ArrayList<Clause>();
+
+	public OrClause(double[] chances, Clause... subClauses) {
+		this.chances = chances;
+		double chanceTotal = 0.0;
+		for (double chance : chances) {
+			chanceTotal += chance;
+		}
+		if (Math.abs(chanceTotal - 1.0) > 0.01) {
+			throw new IllegalArgumentException(
+					"Total or-clause chances must sum to 1.0.");
+		}
+		for (Clause clause : subClauses) {
+			this.subClauses.add(clause);
+		}
+	}
+	
+	@Override
+	public boolean isChoice() {
+		return true;
+	}
+
+	@Override
+	public boolean isTerminal() {
+		return false;
+	}
+	@Override
+	public Clause makeRandomChoice() {
+		double rand = Math.random();
+		for (int i = 0; i < chances.length; i++) {
+			if (rand < chances[i]) {
+				return subClauses.get(i);
+			}
+			rand -= chances[i];
+		}
+		return subClauses.get(chances.length - 1);
+	}
+
+	@Override
+	public int getNumSubClauses() {
+		return subClauses.size();
+	}
+	
+	public Clause getSubClause(int index) {
+		throw new UnsupportedOperationException();
+	}
+	
+	@Override
+	public boolean isVariable() {
+		return false;
+	}
+}