parseevent.java

一个即时消息系统的源码（J2ME编程部分）。

package org.kxml.parser;


import java.util.*;
import java.io.IOException;

import org.kxml.*;


/** Abstract superclass for all pull parser events.  In order to avoid
    some typecasts, this class already provides most of the content
    access methods filled in the specialized subclasses.  */
 

public abstract class ParseEvent {

    int lineNumber = -1;

 

    /** returns the line number of the event */

    public int getLineNumber () {
	return lineNumber;
    }

    /** returns the event type integer constant assigned to this
        event.  Possible event types are Xml.START_TAG, Xml.END_TAG,
        Xml.TEXT, Xml.PROCESSING_INSTRUCTION, Xml.COMMENT,
        Xml.DOCTYPE, and Xml.END_DOCUMENT */
	
    public abstract int getType ();

    
    /** returns true if the event is the matching endtag, false if the
	event is an empty(!) text event, a comment or a processing
	instruction.  Throws an exception if the event is not
	ignoreable. Useful in the default handler of a case construct
	when all relevant events are already picked out */

    public abstract boolean endCheck (StartTag start); 

    
    /** sets the line number of the event. Used by the parser only. */

    public void setLineNumber (int lineNumber) {
	this.lineNumber = lineNumber;
    }


   /** In the event type is START_TAG, this method returns the attribute 
       at the given index position. For all other event
       types, or if the index is out of range, an exception is thrown. */


    public Attribute getAttribute (int index) {
	throw new RuntimeException ("Only start tag events can have attributes.");
    }
    
    
    /** convenience method for getAttribute (null, name). */

    public Attribute getAttribute (String name) {
	return null;
    }


    /** If the event type is START_TAG, the local attribute with the
	given namespace and name is returned.  For all other event
	types, the return value is null. */

    public Attribute getAttribute (String namespace, String name) {

	return null;
    }


    /** If the event type is START_TAG, the number of attributes is
	returned. For all other event types, the return value is null */

    public int getAttributeCount () {
	return 0;
    }


    /** returns the attribute vector. Returns null if not 
        instance of startTag */

    public Vector getAttributes () {
	return null;
    }

    /** returns the (local) name of the element started if
        instance of StartTag, null otherwise. */

    public String getName () {
	return null;
    }


    /** returns namespace if instance of StartTag, null
        otherwise. */ 

    public String getNamespace () {
	return null;
    }


    /** Returns the value of the attribute with the given name.
	Throws an exception if not instanceof StartTag or if not
	existing. In order to get a null value for not existing
	attributes, please call getValueDefault (attrName, null)
	instead. */

    public String getValue (String attrname) {
	throw new RuntimeException ("Only start tags events can have attributes");
    }


    /** Returns the value of the given attribute or the given
	default value, if the attribute is not existing. */

    public String getValueDefault (String attrName, String dflt) {
	return dflt;
    }


    /** If the event type is TEXT, PROCESSING_INSTRUCTION,
	or DOCTYPE, the corresponding string is returned. For
	all othe event types, null is returned. */

    public String getText () {
	return null;
    }
}