XmlToPathTransformerImpl.java

package com.sandwich.koan.path.xmltransformation;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.LinkedHashMap;
import java.util.Map;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.DOMException;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import com.sandwich.koan.path.PathToEnlightenment.Path;

public class XmlToPathTransformerImpl implements XmlToPathTransformer {

	private final File xmlFile;
	private final String suiteName;
	private final String methodName;

	public XmlToPathTransformerImpl(){
		xmlFile = null;
		suiteName = null;
		methodName = null;
	}

	public XmlToPathTransformerImpl(String xmlFileLocation, String suiteName, String methodName) throws FileNotFoundException {
		this.xmlFile = new File(xmlFileLocation);
		this.suiteName = suiteName;
		this.methodName = methodName;
		if(!xmlFile.exists()){
			throw new FileNotFoundException(xmlFile.getAbsolutePath()
				+ " was not found. it may have been deleted, renamed.");
		}
	}
	
	public Path transform(){
		try{
			DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
			DocumentBuilder db = dbf.newDocumentBuilder();
			Document doc = db.parse(xmlFile);
			doc.getDocumentElement().normalize();
			NodeList nodeLst = doc.getElementsByTagName("package");
			/*	
			 * Map of string values read from xml in following form
			 * package
			 * 	  |-suite class name
			 * 		      |-method name
			 * 				     |-method attributes from xml
			 */
			Map<String, Map<String, Map<String, KoanElementAttributes>>> koans = 
				new LinkedHashMap<String, Map<String, Map<String, KoanElementAttributes>>>();
			for(int i = 0; i < nodeLst.getLength(); i++){
				Node node = nodeLst.item(i);
				String packageTitle = node.getAttributes().getNamedItem("name").getNodeValue();
				String pkg = node.getAttributes().getNamedItem("pkg").getNodeValue();
				koans.put(packageTitle, getKoanElementAttributesByMethodNameBySuite(pkg, node.getChildNodes()));
			}
			return new Path(methodName, koans);
		}catch(Exception x){
			throw new RuntimeException(x);
		}
	}
	
	Map<String, Map<String, KoanElementAttributes>> getKoanElementAttributesByMethodNameBySuite(String pkg,
			NodeList childNodes) throws DOMException, ClassNotFoundException,
			InstantiationException, IllegalAccessException {
		Map<String, Map<String, KoanElementAttributes>> koansByMethodNameByClass = 
			new LinkedHashMap<String, Map<String, KoanElementAttributes>>();
		for (int i = 0; i < childNodes.getLength(); i++) {
			Node node = childNodes.item(i);
			if ("suite".equalsIgnoreCase(node.getNodeName())) {
				String className = pkg + '.' + node.getAttributes().getNamedItem("class").getNodeValue();
				if (suiteName == null || suiteName.equalsIgnoreCase(className)) {
					koansByMethodNameByClass.put(className, extractKoansAndRawLessons(className, node.getChildNodes()));
				}
			}
		}
		return koansByMethodNameByClass;
	}

	Map<String, KoanElementAttributes> extractKoansAndRawLessons(
			String className, NodeList nodes) {
		Map<String, KoanElementAttributes> rawKoanAttributesByMethodName = new LinkedHashMap<String, KoanElementAttributes>();
		for (int i = 0; i < nodes.getLength(); i++) {
			Node node = nodes.item(i);
			if ("koan".equalsIgnoreCase(node.getNodeName())) {
				NamedNodeMap attributes = node.getAttributes();
				String name = attributes.getNamedItem("name").getNodeValue();
				Node displayKoanIncompleteExceptionNode = attributes
						.getNamedItem("displayIncompleteKoanException");
				String displayIncompleteKoanException = displayKoanIncompleteExceptionNode == null ? null
						: displayKoanIncompleteExceptionNode.getNodeValue();
				if (rawKoanAttributesByMethodName.containsKey(name)) {
					throw new DuplicateKoanException(className, name);
				}
				rawKoanAttributesByMethodName.put(name, new KoanElementAttributes(
					name, displayIncompleteKoanException, className));
			}
		}
		return rawKoanAttributesByMethodName;
	}

	static class DuplicateKoanException extends RuntimeException {
		private static final long serialVersionUID = 3846796580641690961L;
		public DuplicateKoanException(String className, String name){
			super("Duplicate koans in the same suite: "+className+" with the name "+name);
		}
	}

}