PomXml.java

package org.vaadin.mideaas.frontend;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.LinkedList;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerFactoryConfigurationError;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

public class PomXml {
	
	public static class Dependency {
		public String groupId;
		public String artifactId;
		public String version;
		public Dependency(String groupId, String artifactId, String version) {
			this.groupId = groupId;
			this.artifactId = artifactId;
			this.version = version;
		}
		public Dependency() {
			// TODO Auto-generated constructor stub
		}
		@Override
		public boolean equals(Object obj) {
			if (obj instanceof Dependency) {
				Dependency od = (Dependency)obj;
				return groupId.equals(od.groupId) && artifactId.equals(od.artifactId) && version.equals(od.version);
			}
			return false;
		}
		@Override
		public int hashCode() {
			return groupId.hashCode(); // XXX
		}
	}
	
	private Document doc;
	private String str;
	private boolean dirty;
	
	public PomXml(String value) throws ParserConfigurationException, SAXException, IOException {
		setValue(value);
	}
	
	public String getAsString() throws TransformerFactoryConfigurationError, TransformerException {
		if (dirty) {
			docToString();
		}
		return str;
	}
	
	private void docToString() throws TransformerFactoryConfigurationError, TransformerException {
		Transformer trer = TransformerFactory.newInstance().newTransformer();
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		StreamResult result = new StreamResult(baos);
		trer.transform(new DOMSource(doc), result);
		str = baos.toString();
	}
	
	public void setValue(String value) throws ParserConfigurationException, SAXException, IOException {
		if(value.equals(str)) {
			return;
		}
		DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
		doc = builder.parse(new InputSource(new ByteArrayInputStream(value.getBytes("utf-8"))));
		dirty = true;
	}
	
	public void addDependency(String groupId, String artifactId, String version) {
		Element d = doc.createElement("dependency");

		Element gid = doc.createElement("groupId");
		gid.appendChild(doc.createTextNode(groupId));
		d.appendChild(gid);
		
		Element aid = doc.createElement("artifactId");
		aid.appendChild(doc.createTextNode(artifactId));
		d.appendChild(aid);
		
		Element vid = doc.createElement("version");
		vid.appendChild(doc.createTextNode(version));
		d.appendChild(vid);
		
		getDepsNode().appendChild(d);
		
		dirty = true;
	}
	

	
	public void addDependency(String xmlSnippet) throws ParserConfigurationException, UnsupportedEncodingException, SAXException, IOException {
		DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
		Document doc = builder.parse(new InputSource(new ByteArrayInputStream(xmlSnippet.getBytes("utf-8"))));
		String groupId = doc.getElementsByTagName("groupId").item(0).getFirstChild().getNodeValue();
		String artifactId = doc.getElementsByTagName("artifactId").item(0).getFirstChild().getNodeValue();
		String version = doc.getElementsByTagName("version").item(0).getFirstChild().getNodeValue();
		addDependency(groupId, artifactId, version);
	}
	
	public List<Dependency> getDependencies() {
		NodeList deps = getDepsNode().getChildNodes();
		LinkedList<Dependency> dl = new LinkedList<Dependency>();
		for (int i=0; i<deps.getLength(); i++) {
			Dependency dep = depFromNode(deps.item(i));
			if (dep!=null) {
				dl.add(dep);
			}
		}
		return dl;
	}
	
	private Node getDepsNode() {
		return doc.getElementsByTagName("dependencies").item(0);
	}
	
	public void removeDependency(Dependency dep) {
		NodeList deps = getDepsNode().getChildNodes();
		for (int i=0; i<deps.getLength(); i++) {
			Dependency d2 = depFromNode(deps.item(i)); // XXX
			if (d2 != null && d2.equals(dep)) {
				getDepsNode().removeChild(deps.item(i));
				break;
			}
		}
	}
	
	private static Dependency depFromNode(Node node) {
		NodeList children = node.getChildNodes();
		Dependency dep = new Dependency();
		int all = 0;
		for (int i=0; i<children.getLength(); i++) {
			Node c = children.item(i);
			if (c.getFirstChild()==null) {
				continue;
			}
			if ("groupId".equals(c.getNodeName())) {
				dep.groupId = c.getFirstChild().getNodeValue();
				all |= 1;
			}
			else if ("artifactId".equals(c.getNodeName())) {
				dep.artifactId = c.getFirstChild().getNodeValue();
				all |= 2;
			}
			else if ("version".equals(c.getNodeName())) {
				dep.version = c.getFirstChild().getNodeValue();
				all |= 4;
			}
		}
		
		return all==7 ? dep : null;
	}
	
	
}