Event Example (The Java EE 5 Tutorial)

The Java EE 5 Tutorial

Event Example

Located in the tut-install/javaeetutorial5/examples/stax/event/ directory, EventParse.java demonstrates how to use the StAX event API to read an XML document.

Creating an Input Factory

The first step is to create a new instance of XMLInputFactory:

XMLInputFactory factory = XMLInputFactory.newInstance();
System.out.println("FACTORY: " + factory);

Creating an Event Reader

The next step is to create an instance of XMLEventReader:

XMLEventReader r = factory.createXMLEventReader(filename,
     new FileInputStream(filename));

Creating an Event Iterator

The third step is to create an event iterator:

XMLEventReader r = factory.createXMLEventReader(filename,
     new FileInputStream(filename));
while(r.hasNext()) {
    XMLEvent e = r.nextEvent();
    System.out.println(e.toString());
}

Getting the Event Stream

The final step is to get the underlying event stream:

public final static String getEventTypeString(int eventType) {
    switch (eventType) {
        case XMLEvent.START_ELEMENT:
            return "START_ELEMENT";
        case XMLEvent.END_ELEMENT:
            return "END_ELEMENT";
        case XMLEvent.PROCESSING_INSTRUCTION:
            return "PROCESSING_INSTRUCTION";
        case XMLEvent.CHARACTERS:
            return "CHARACTERS";
        case XMLEvent.COMMENT:
            return "COMMENT";
        case XMLEvent.START_DOCUMENT:
            return "START_DOCUMENT";
        case XMLEvent.END_DOCUMENT:
            return "END_DOCUMENT";
        case XMLEvent.ENTITY_REFERENCE:
            return "ENTITY_REFERENCE";
        case XMLEvent.ATTRIBUTE:
            return "ATTRIBUTE";
        case XMLEvent.DTD:
            return "DTD";
        case XMLEvent.CDATA:
            return "CDATA";
        case XMLEvent.SPACE:
            return "SPACE";
    }
    return "UNKNOWN_EVENT_TYPE " + "," + eventType;
}

Returning the Output

When you run the Event example, the EventParse class is compiled, and the XML stream is parsed as events and returned to STDOUT. For example, an instance of the Author element is returned as:

<[’http://www.publishing.org’]::Author>
    Dhirendra Brahmachari
</[’http://www.publishing.org’]::Author>

Note in this example that the event comprises an opening and closing tag, both of which include the namespace. The content of the element is returned as a string within the tags.

Similarly, an instance of the Cost element is returned as:

<[’http://www.publishing.org’]::Cost currency=’INR’>
    11.50
</[’http://www.publishing.org’]::Cost>

In this case, the currency attribute and value are returned in the opening tag for the event.

Building and Running the Event Example Using NetBeans IDE

Follow these instructions to build and run the Event example on your Application Server instance using the NetBeans IDE.

In NetBeans IDE, select File->Open Project.
In the Open Project dialog, navigate to the tut-install/javaeetutorial5/examples/stax/ directory.
Select the event folder.
Select the Open as Main Project check box.
Click Open Project.
In the Projects tab, right-click the event project and select Properties. The Project Properties dialog is displayed.
Enter the following in the Arguments field:
BookCatalog.xml
Click OK.
Right-click the event project and select Run.

Building and Running the Event Example Using Ant

To compile and run the Event example using Ant, in a terminal window, go to the tut-install/javaeetutorial5/examples/stax/event/ directory and type the following:

ant run-event