/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.wicket.ajax;
import org.apache.wicket.Page;
import org.apache.wicket.RequestCycle;
import org.apache.wicket.markup.html.IHeaderResponse;
import org.apache.wicket.protocol.http.WebRequest;
import org.apache.wicket.util.time.Duration;
/**
* A behavior that generates an AJAX update callback at a regular interval.
*
* @since 1.2
*
* @author Igor Vaynberg (ivaynberg)
*
*/
public abstract class AbstractAjaxTimerBehavior extends AbstractDefaultAjaxBehavior
{
/**
*
*/
private static final long serialVersionUID = 1L;
/** The update interval */
private Duration updateInterval;
private boolean stopped = false;
private boolean headRendered = false;
/**
* Construct.
*
* @param updateInterval
* Duration between AJAX callbacks
*/
public AbstractAjaxTimerBehavior(final Duration updateInterval)
{
if (updateInterval == null || updateInterval.getMilliseconds() <= 0)
{
throw new IllegalArgumentException("Invalid update interval");
}
this.updateInterval = updateInterval;
}
/**
* Stops the timer
*/
public final void stop()
{
stopped = true;
}
/**
* Sets the update interval duration. This method should only be called within the
* {@link #onTimer(AjaxRequestTarget)} method.
*
* @param updateInterval
*/
protected final void setUpdateInterval(Duration updateInterval)
{
if (updateInterval == null || updateInterval.getMilliseconds() <= 0)
{
throw new IllegalArgumentException("Invalid update interval");
}
this.updateInterval = updateInterval;
}
/**
* Returns the update interval
*
* @return The update interval
*/
public final Duration getUpdateInterval()
{
return updateInterval;
}
/**
* @see org.apache.wicket.behavior.AbstractAjaxBehavior#renderHead(org.apache.wicket.markup.html.IHeaderResponse)
*/
public void renderHead(IHeaderResponse response)
{
super.renderHead(response);
WebRequest request = (WebRequest)RequestCycle.get().getRequest();
if (!stopped && (!headRendered || !request.isAjax()))
{
headRendered = true;
response.renderOnLoadJavascript(getJsTimeoutCall(updateInterval));
}
}
/**
* @param updateInterval
* Duration between AJAX callbacks
* @return JS script
*/
protected final String getJsTimeoutCall(final Duration updateInterval)
{
// this might look strange, but it is necessary for IE not to leak :(
return "setTimeout(\"" + getCallbackScript() + "\", " + updateInterval.getMilliseconds() +
");";
}
protected CharSequence getCallbackScript()
{
return generateCallbackScript("wicketAjaxGet('" + getCallbackUrl(onlyTargetActivePage()) +
"'");
}
/**
* @see org.apache.wicket.ajax.AbstractDefaultAjaxBehavior#getPreconditionScript()
*/
protected CharSequence getPreconditionScript()
{
String precondition = null;
if (!(getComponent() instanceof Page))
{
String componentId = getComponent().getMarkupId();
precondition = "var c = Wicket.$('" + componentId +
"'); return typeof(c) != 'undefined' && c != null";
}
return precondition;
}
protected boolean onlyTargetActivePage()
{
return true;
}
/**
*
* @see org.apache.wicket.ajax.AbstractDefaultAjaxBehavior#respond(org.apache.wicket.ajax.AjaxRequestTarget)
*/
protected final void respond(final AjaxRequestTarget target)
{
onTimer(target);
if (!stopped)
{
target.getHeaderResponse().renderOnLoadJavascript(getJsTimeoutCall(updateInterval));
}
}
/**
* Listener method for the AJAX timer event.
*
* @param target
* The request target
*/
protected abstract void onTimer(final AjaxRequestTarget target);
}