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Data Importer

Data Importer. The Main Routine. In these notes I call it DataImporter . It contains: A main routine the creates an instance of IndexerData , the root of our data model. It has two supplemental static methods that make our job much easier. ArrayList <Element> getChildElements (Node)

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Data Importer

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  1. Data Importer

  2. The Main Routine • In these notes I call it DataImporter. It contains: • A main routine the creates an instance of IndexerData, the root of our data model. • It has two supplemental static methods that make our job much easier. • ArrayList<Element> getChildElements(Node) • String getValue(Element)

  3. Setting It Up // When in conflict use the class from org.w3c.dom. // Examples: Document, Element, Node, NodeList File xmlFile = new File("Records.xml"); DocumentBuilderFactorydbFactory = DocumentBuilderFactory.newInstance(); DocumentBuilderdBuilder = dbFactory.newDocumentBuilder(); Document doc = dBuilder.parse(xmlFile); //Can use URI instead of xmlFile //optional, but recommended. Read this // http://stackoverflow.com/questions/13786607/normalization-in-dom-parsing-with-java-how-does-it-work doc.getDocumentElement().normalize(); Element root = doc.getDocumentElement(); indexerData = new IndexerData(root);

  4. getChildElements(not needed if you only usegetElementsbyTagName(String)) public static ArrayList<Element> getChildElements(Node node) { ArrayList<Element> result = new ArrayList<Element>(); NodeListchildren = node.getChildNodes(); for(inti = 0; i < children.getLength(); i++) { Node child = children.item(i); if(child.getNodeType() == Node.ELEMENT_NODE){ result.add((Element)child); } } return result; }

  5. getValue public static String getValue(Element element) { String result = ""; Node child = element.getFirstChild(); result = child.getNodeValue(); return result; }

  6. The Class IndexerData //An Example of how to use “DataImporter.getChildElements(Element) public class IndexerData { private ArrayList<User> users = new ArrayList<User>(); private ArrayList<Project> projects = new ArrayList<Project>(); public IndexerData(Element root) { ArrayList<Element> rootElements = DataImporter.getChildElements(root); ArrayList<Element> userElements = DataImporter.getChildElements(rootElements.get(0)); for(Element userElement : userElements) { users.add(new User(userElement)); } ArrayList<Element> projectElements = DataImporter.getChildElements(rootElements.get(1)); for(Element projectElement : projectElements) { projects.add(new Project(projectElement)); } } }

  7. Using “getElementsByTagName” and“DataImporter.getValue(Element), public class Project { private String title = null; private intrecordsPerImage = -1; private intfirstYCoord = -1; private intrecordHeight = -1; ArrayList<Field> fields = new ArrayList<Field>(); ArrayList<Image> images = new ArrayList<Image>(); public Project(Element projectElement) { title = DataImporter.getValue((Element)projectElement.getElementsByTagName("title").item(0)); recordsPerImage = Integer.parseInt(DataImporter.getValue( (Element)projectElement.getElementsByTagName("recordsperimage").item(0))); firstYCoord = Integer.parseInt(DataImporter.getValue( (Element)projectElement.getElementsByTagName("firstycoord").item(0))); recordHeight = Integer.parseInt(DataImporter.getValue( (Element)projectElement.getElementsByTagName("recordheight").item(0))); Element fieldsElement = (Element)projectElement.getElementsByTagName("fields").item(0); NodeListfieldElements = fieldsElement.getElementsByTagName("field"); for(inti = 0; i < fieldElements.getLength(); i++) { fields.add(new Field((Element)fieldElements.item(i))); } ElementimagesElement = (Element)projectElement.getElementsByTagName("images").item(0); NodeListimageElements = imagesElement.getElementsByTagName("image"); for(inti = 0; i < imageElements.getLength(); i++) { images.add(new Image((Element)imageElements.item(i))); } } }

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