Add BooleanCovariate

src/main/java/ca/joeltherrien/randomforest/BooleanCovariate.java

@@ -0,0 +1,72 @@
+package ca.joeltherrien.randomforest;
+
+import ca.joeltherrien.randomforest.exceptions.MissingValueException;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+import java.util.*;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.stream.Collectors;
+
+@RequiredArgsConstructor
+public class BooleanCovariate implements Covariate<Boolean>{
+
+    @Getter
+    private final String name;
+
+    private final BooleanSplitRule splitRule = new BooleanSplitRule(); // there's only one possible rule for BooleanCovariates.
+
+    @Override
+    public Collection<BooleanSplitRule> generateSplitRules(List<Value<Boolean>> data, int number) {
+        return Collections.singleton(splitRule);
+    }
+
+    @Override
+    public BooleanValue createValue(Boolean value) {
+        return new BooleanValue(value);
+    }
+
+    public class BooleanValue implements Value<Boolean>{
+
+        private final boolean value;
+
+        private BooleanValue(final boolean value){
+            this.value = value;
+        }
+
+        @Override
+        public BooleanCovariate getParent() {
+            return BooleanCovariate.this;
+        }
+
+        @Override
+        public Boolean getValue() {
+            return value;
+        }
+    }
+
+    public class BooleanSplitRule implements SplitRule<Boolean>{
+
+        @Override
+        public final String toString() {
+            return "BooleanSplitRule";
+        }
+
+        @Override
+        public BooleanCovariate getParent() {
+            return BooleanCovariate.this;
+        }
+
+        @Override
+        public boolean isLeftHand(CovariateRow row) {
+            final Value<?> x = row.getCovariateValue(getParent().getName());
+            if(x == null) {
+                throw new MissingValueException(row, this);
+            }
+
+            final boolean xBoolean = (Boolean) x.getValue();
+
+            return !xBoolean;
+        }
+    }
+}