Tutorial: Casablanca

Question 1: Director

The input for this program is the file casablanca.xml

We are initially interested in the element:

<director>Michael Curtiz</director>

Observe that the program prints the director of the movie.
Change the program so that it outputs the title of the movie followed by the year in brackets. Casablanca (1944) Note that this data is held in a node:
```
<title year="1942">Casablanca</title>
```
Hint
- You will need to create a global variable to store the year every time you start an element with name title. yr = atts.getValue("year"); - yr must be declared outside the method.
- Change the printOn so it is set for title elements rather than director elements.
- Change the println to include the title. System.out.println((new String (t,s,l)) + "(" + yr + ")");
Change the program so that is prints the name of the actor playing "Victor Laszlo".
Hint
- We can rely on the fact that the text node that comes before "Victor Laszlo" will be the name of the actor playing that part. All we need do is record the "previous" text node.:
```
    if ("Victor Laszlo".equals(new String(t,s,l)))
       System.out.println(prevText);
    prevText = new String(t,s,l);
```
  prevText must be declared outside the method.
The previous example was fixed! The casablance.xml file has no redundant white space in it. The file casablanca2.xml does have redundant white space (as is common in XML documents). Change class S so that loads casablanca2.xml Does it still work?
Hint

Two possible solutions...
(A) switch on validation - this forces the ignorable white space to be prcessed by calls to ignorableWhiteSpace and not come through characters. See http://www.saxproject.org/apidoc/org/xml/sax/XMLReader.html#getFeature(java. lang.String) for details.
(B) Only set prevText is prevNode is actor - you will have to set prevNode in startElement

Content Handler

import org.xml.sax.*;

public class MyHandler implements ContentHandler {

boolean printOn;

public void startDocument() throws SAXException
  {
    printOn=false;
  }

public void startElement(String namespaceURI, String localName,
   String qualifiedName, Attributes atts) throws SAXException
  {
    printOn = (localName.equals("director"));
  }

public void characters(char[] t, int s, int l) throws SAXException
  {
    if (printOn)
      System.out.print(new String(t,s,l));
    printOn=false;
  }

// Do-nothing methods
  public void endDocument() throws SAXException { }
  public void endElement(String namespaceURI, String localName,
   String qualifiedName) throws SAXException { }
  public void endPrefixMapping(String p) throws SAXException {}
  public void processingInstruction(String t, String d) throws SAXException {}
  public void setDocumentLocator(Locator l) {}
  public void skippedEntity(String n) throws SAXException {}
  public void startPrefixMapping(String p, String u) throws SAXException {}
  public void ignorableWhitespace(char[] t, int s, int l)throws SAXException{}
}

A Gentle Introduction to xml

Casablanca

Question 1: Director

Content Handler

Java SAX