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Hi,
I modified the example from WIKI Long Operations/Use Event Queues a bit for my issue but it does not work as expected.
<window title="test of long operation" border="normal">
<html><![CDATA[
<ul>
<li>Click the button it will start a long operation.</li>
<li>With this implementation, you can press the button again even if
the long operation is still being processed</li>
</ul>
]]></html>
<zscript>
void print(String msg) {
new Label(msg).setParent(inf);
}
</zscript>
<button label="async long op">
<attribute name="onClick"><![CDATA[
if (EventQueues.exists("longop")) {
print("It is busy. Please wait");
return; //busy
}
EventQueue eq = EventQueues.lookup("longop"); //create a queue
String result;
//subscribe async listener to handle long operation
eq.subscribe(new EventListener() {
public void onEvent(Event evt) {
if ("doLongOp".equals(evt.getName())) {
eq.publish(new Event("reloadView")); //notify
org.zkoss.lang.Threads.sleep(5000); //simulate a long operation
result = "success"; //store the result
eq.publish(new Event("endLongOp")); //notify it is done
}
}
}, true); //asynchronous
//subscribe a normal listener to show the resul to the browser
eq.subscribe(new EventListener() {
public void onEvent(Event evt) {
if ("endLongOp".equals(evt.getName())) {
print(result); //show the result to the browser
EventQueues.remove("longop");
}
if ("reloadView".equals(evt.getName())) {
print("TIMER: " + new Date().getSeconds());
Thread.sleep(1000);
eq.publish(new Event("reloadView")); // notify to reload of view
}
}
}); //synchronous
print("Wait for 5 seconds");
eq.publish(new Event("doLongOp")); //kick off the long operation
]]></attribute>
</button>
<vbox id="inf"></vbox>
</window>
What I want to do is:
While the long operation runs (in my real case I import data from a file into a database table), I want to refresh a listbox that shows a log table from database.
So my idea was to publish another event to the queue that does the refresh every second.
In the code above simulated by the
print("TIMER: " + new Date().getSeconds());
After one second I publish the event again.
My expectation was to see the word TIMER every second.
But it only shows up once at the end of the long operation.
What am I doing wrong?
Thanks for any help!
You should either use a working thread, or a Timer. The problem is that there is only one execution thread in ZK (by default configuration), thus when thread sleeps, nothing happens. Below is the working code with Timer implementation:
<window title="test of long operation" border="normal">
<html><![CDATA[
<ul>
<li>Click the button it will start a long operation.</li>
<li>With this implementation, you can press the button again even if
the long operation is still being processed</li>
</ul>
]]></html>
<zscript>
void print(String msg) {
new Label(msg).setParent(inf);
}
</zscript>
<button label="async long op">
<attribute name="onClick"><![CDATA[
if (EventQueues.exists("longop")) {
print("It is busy. Please wait");
return; //busy
}
EventQueue eq = EventQueues.lookup("longop"); //create a queue
String result;
timer.start();
//subscribe async listener to handle long operation
eq.subscribe(new org.zkoss.zk.ui.event.EventListener() {
public void onEvent(Event evt) {
if ("doLongOp".equals(evt.getName())) {
org.zkoss.lang.Threads.sleep(5000); //simulate a long operation
result = "success"; //store the result
eq.publish(new Event("endLongOp")); //notify it is done
}
}
}, true); //asynchronous
//subscribe a normal listener to show the resul to the browser
eq.subscribe(new org.zkoss.zk.ui.event.EventListener() {
public void onEvent(Event evt) {
if ("endLongOp".equals(evt.getName())) {
timer.stop();
print(result); //show the result to the browser
EventQueues.remove("longop");
}
}
}); //synchronous
print("Wait for 5 seconds");
eq.publish(new Event("doLongOp")); //kick off the long operation
]]></attribute>
</button>
<vbox id="inf"></vbox>
<timer id="timer" running="false" delay="1000" repeats="true">
<attribute name="onTimer">
print("timer called.");
</attribute>
</timer>
</window>
Asked: 2012-09-04 19:13:38 +0800
Seen: 183 times
Last updated: Sep 10 '12