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https://issues.apache.org/jira/browse/XERCESJ-1429?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13051579#comment-13051579
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Thiwanka Somasiri commented on XERCESJ-1429:
--------------------------------------------
Hi Michael,
I have modified the class to add and remove listeners & made the changes
you have asked. I used a similar way to add and remove listeners as it is in
DocumentImpl class implementation. The modified class is as follows.
Note: When a user tries to use the AsyncLSParser, he can check whether the
parser is busy using the getBusy() method. But, if the user tries to access the
parse() method without checking the busy flag, it should not be allowed. So I
suggest to throw an exception when trying to set the busy flag(when invoking
setBusyFlag() in parse() method) in to "true" where it is already set to
"true". Hope your opinion on this.
public class AsynchronousDOMParserImpl extends DOMParserImpl implements
EventTarget{
//Create the HashSet to hold the event listeners that the users are
subscribed to
private Hashtable eventListeners;
private DOMParserImpl parser;
private volatile boolean fBusy = false;//TODO make this volatile to avoid
other threads using the async parser when busy
//private LSInput ls;
//Call the super class constructors - there are four constructors in the
DOMParserImpl class
public AsynchronousDOMParserImpl(String configuration, String schemaType){
super(configuration, schemaType); //Check whether these super()
should be removed or not
parser = new DOMParserImpl(configuration, schemaType);
}
public AsynchronousDOMParserImpl(XMLParserConfiguration config){
super(config);
parser = new DOMParserImpl(config);
}
public AsynchronousDOMParserImpl(SymbolTable symbolTable){
super(symbolTable);
parser = new DOMParserImpl(symbolTable);
}
public AsynchronousDOMParserImpl(SymbolTable symbolTable, XMLGrammarPool
grammarPool){
super(symbolTable, grammarPool);
parser = new DOMParserImpl(symbolTable, grammarPool);
}
public void addEventListener(String type, EventListener listener, boolean
useCapture){
if (type == null || type.length() == 0 || listener == null)
return;
//Remove the previous entry for the same EventListener
//removeEventListener(type, listener, useCapture);
Vector listeners = getEventListeners(type);
if(listeners == null) {
listeners = new Vector();
setEventListeners(type, listeners);
}
listeners .addElement(new ListenerHolder(listener, useCapture));
}
private Vector getEventListeners(String type){
if (eventListeners == null) {
return null;
}
return (Vector) eventListeners.get(type);
}
private void setEventListeners(String type, Vector listeners){
if (eventListeners == null) {
eventListeners = new Hashtable();
}
eventListeners.put(type, listeners);
}
public void removeEventListener(String type, EventListener listener,
boolean useCapture){
if (type == null || type.length() == 0 || listener == null)
return;
//If the vector is null for a particular type it will return
Vector listeners = getEventListeners(type);
if (listeners == null)
return;
//If the vector is not null, compare the listener and useCapture and
remove the listener
for(int i = 0; i < listeners.size(); i++){
ListenerHolder lh = (ListenerHolder) listeners.get(i);
if(lh.useCapture == useCapture && lh.el == listener){
listeners.removeElementAt(i);
//TODO assign null value in to hashtable when the vector is
empty
break;
}
}
}
public boolean dispatchEvent(Event evt){
return false;//TODO change the return value
}
public Document parse(LSInput is){
final LSInput ls = is;
setBusyFlag();
//____________________________________
Runnable target = new Runnable() {
@Override
public void run() {
try{
parser.parse(ls);
}catch(LSException e){
e.printStackTrace();
}finally{
resetBusyFlag();
}
}
};
//____________________________________
//AsynchronousDOMParserImpl.AsyncInnerParser target = new
AsynchronousDOMParserImpl.AsyncInnerParser();
Thread t = new Thread(target);
t.start();
return null;
}
public void setBusyFlag(){
fBusy = true;
}
public void resetBusyFlag(){
fBusy = false;
}
public boolean getBusy () {
return fBusy;
}
/*class AsyncInnerParser implements Runnable{
public void run(){
try{
parser.parse(ls);
}catch(LSException e){
e.printStackTrace();
}finally{
resetBusyFlag();
}
}
}*/
//This structure holds the EventListner associated with it
class ListenerHolder{
EventListener el;
boolean useCapture;
ListenerHolder(EventListener el, boolean useCapture) {
this.el = el;
this.useCapture = useCapture;
}
}
}
> [GSoC]: Asynchronous LSParser and parseWithContext
> --------------------------------------------------
>
> Key: XERCESJ-1429
> URL: https://issues.apache.org/jira/browse/XERCESJ-1429
> Project: Xerces2-J
> Issue Type: New Feature
> Components: DOM (Level 3 Load & Save)
> Affects Versions: 2.9.1
> Reporter: Michael Glavassevich
> Labels: gsoc2011
>
> The goal of this project is to complete the implementation of the DOM Level 3
> LSParser. Though Xerces has a functional LSParser, there are a couple parts
> of the spec which still need to be implemented. This includes an asynchronous
> [1] version which returns from the parse method immediately and builds the
> DOM tree on another thread as well as parseWithContext [2] which allows a
> document fragment to be parsed and attached to an existing DOM.
> Possible Mentors: Michael Glavassevich
> [1]
> http://www.w3.org/TR/2004/REC-DOM-Level-3-LS-20040407/load-save.html#LS-LSParser
> [2]
> http://www.w3.org/TR/2004/REC-DOM-Level-3-LS-20040407/load-save.html#LS-LSParser-parseWithContext
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