### Question:
CategoricalDecision extends Decision { @Override public boolean isPositive(Example example) { CategoricalFeature feature = (CategoricalFeature) example.getFeature(getFeatureNumber()); if (feature == null) { return defaultDecision; } int encoding = feature.getEncoding(); if (encoding >= activeCategoryEncodings.size()) { return defaultDecision; } return activeCategoryEncodings.get(encoding); } CategoricalDecision(int featureNumber,
                             BitSet activeCategoryEncodings,
                             boolean defaultDecision); @Override boolean getDefaultDecision(); BitSet getActiveCategoryEncodings(); @Override boolean isPositive(Example example); @Override FeatureType getType(); @Override boolean equals(Object o); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void testDecision() { BitSet activeCategories = new BitSet(10); activeCategories.set(2); activeCategories.set(5); Decision decision = new CategoricalDecision(0, activeCategories, true); for (int i = 0; i < 10; i++) { assertEquals(activeCategories.get(i), decision.isPositive(new Example(null, CategoricalFeature.forEncoding(i)))); } assertTrue(decision.isPositive(new Example(null, new Feature[] {null}))); }