15.1 AN EXAMPLE CLASSIFIER 479
*
* @param level the level at which the tree is to be printed
*/
private String toString(int level) {StringBuffer text = new StringBuffer();if (m_Attribute == null) {
if (Instance.isMissingValue(m_ClassValue)) {
text.append(": null");
} else {
text.append(": " + m_ClassAttribute.value((int) m_ClassValue));
}
} else {
for (int j = 0; j < m_Attribute.numValues(); j++) {
text.append("\n");
for (int i = 0; i < level; i++) {
text.append("| ");
}
text.append(m_Attribute.name() + " = " + m_Attribute.value(j));
text.append(m_Successors[j].toString(level + 1));
}
}
return text.toString();
}/**
* Main method.
*
* @param args the options for the classifier
*/
public static void main(String[] args) {try {
System.out.println(Evaluation.evaluateModel(new Id3(), args));
} catch (Exception e) {
System.err.println(e.getMessage());
}
}
}Figure 15.1(continued)