/*
* 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.Application;
import org.apache.wicket.Component;
import org.apache.wicket.Page;
import org.apache.wicket.behavior.AbstractAjaxBehavior;
import org.apache.wicket.markup.html.IHeaderContributor;
import org.apache.wicket.markup.html.IHeaderResponse;
import org.apache.wicket.markup.html.WicketEventReference;
import org.apache.wicket.protocol.http.WebApplication;
import org.apache.wicket.request.Url;
import org.apache.wicket.request.cycle.RequestCycle;
import org.apache.wicket.request.resource.JavaScriptResourceReference;
import org.apache.wicket.request.resource.PackageResourceReference;
import org.apache.wicket.request.resource.ResourceReference;
import org.apache.wicket.settings.IDebugSettings;
import org.apache.wicket.util.string.AppendingStringBuffer;
import org.apache.wicket.util.string.Strings;
import org.apache.wicket.util.time.Duration;
/**
* The base class for Wicket's default AJAX implementation.
*
* @since 1.2
*
* @author Igor Vaynberg (ivaynberg)
*
*/
public abstract class AbstractDefaultAjaxBehavior extends AbstractAjaxBehavior
{
private static final long serialVersionUID = 1L;
/** reference to the default indicator gif file. */
public static final ResourceReference INDICATOR = new PackageResourceReference(
AbstractDefaultAjaxBehavior.class, "indicator.gif");
/** reference to the default ajax debug support javascript file. */
private static final ResourceReference JAVASCRIPT_DEBUG = new JavaScriptResourceReference(
AbstractDefaultAjaxBehavior.class, "wicket-ajax-debug.js");
/**
* Subclasses should call super.onBind()
*
* @see org.apache.wicket.behavior.AbstractAjaxBehavior#onBind()
*/
@Override
protected void onBind()
{
getComponent().setOutputMarkupId(true);
}
/**
* @see org.apache.wicket.behavior.AbstractAjaxBehavior#renderHead(Component,org.apache.wicket.markup.html.IHeaderResponse)
*/
@Override
public void renderHead(Component component, IHeaderResponse response)
{
super.renderHead(component, response);
response.renderJavaScriptReference(WicketEventReference.INSTANCE);
response.renderJavaScriptReference(WicketAjaxReference.INSTANCE);
final IDebugSettings debugSettings = Application.get().getDebugSettings();
if (debugSettings.isAjaxDebugModeEnabled())
{
response.renderJavaScriptReference(JAVASCRIPT_DEBUG);
response.renderJavaScript("wicketAjaxDebugEnable=true;", "wicket-ajax-debug-enable");
}
Url baseUrl = RequestCycle.get().getUrlRenderer().getBaseUrl();
CharSequence ajaxBaseUrl = Strings.escapeMarkup(baseUrl.toString());
response.renderJavaScript("Wicket.Ajax.baseUrl=\"" + ajaxBaseUrl + "\";",
"wicket-ajax-base-url");
final IAjaxCallDecorator ajaxCallDecorator = getAjaxCallDecorator();
if (ajaxCallDecorator instanceof IHeaderContributor)
{
IHeaderContributor contributor = (IHeaderContributor)ajaxCallDecorator;
contributor.renderHead(component, response);
}
}
/**
* @return ajax call decorator used to decorate the call generated by this behavior or null for
* none
*/
protected IAjaxCallDecorator getAjaxCallDecorator()
{
return null;
}
/**
* @return javascript that will generate an ajax GET request to this behavior
*/
protected CharSequence getCallbackScript()
{
return generateCallbackScript("wicketAjaxGet('" + getCallbackUrl() + "'");
}
/**
* @return an optional javascript expression that determines whether the request will actually
* execute (in form of return XXX;);
*/
protected CharSequence getPreconditionScript()
{
if (getComponent() instanceof Page)
{
return "return true;";
}
else
{
return "return Wicket.$('" + getComponent().getMarkupId() + "') != null;";
}
}
/**
* @return javascript that will run when the ajax call finishes with an error status
*/
protected CharSequence getFailureScript()
{
return null;
}
/**
* @return javascript that will run when the ajax call finishes successfully
*/
protected CharSequence getSuccessScript()
{
return null;
}
/**
* Returns javascript that performs an ajax callback to this behavior. The script is decorated
* by the ajax callback decorator from
* {@link AbstractDefaultAjaxBehavior#getAjaxCallDecorator()}.
*
* @param partialCall
* JavaScript of a partial call to the function performing the actual ajax callback.
* Must be in format <code>function(params,</code> with signature
* <code>function(params, onSuccessHandler, onFailureHandler</code>. Example:
* <code>wicketAjaxGet('callbackurl'</code>
*
* @return script that performs ajax callback to this behavior
*/
protected CharSequence generateCallbackScript(final CharSequence partialCall)
{
final CharSequence onSuccessScript = getSuccessScript();
final CharSequence onFailureScript = getFailureScript();
final CharSequence precondition = getPreconditionScript();
final IAjaxCallDecorator decorator = getAjaxCallDecorator();
String indicatorId = findIndicatorId();
CharSequence success = (onSuccessScript == null) ? "" : onSuccessScript;
CharSequence failure = (onFailureScript == null) ? "" : onFailureScript;
if (decorator != null)
{
success = decorator.decorateOnSuccessScript(getComponent(), success);
}
if (!Strings.isEmpty(indicatorId))
{
String hide = ";Wicket.hideIncrementally('" + indicatorId + "');";
success = success + hide;
failure = failure + hide;
}
if (decorator != null)
{
failure = decorator.decorateOnFailureScript(getComponent(), failure);
}
AppendingStringBuffer buff = new AppendingStringBuffer(256);
buff.append("var ").append(IAjaxCallDecorator.WICKET_CALL_RESULT_VAR).append("=");
buff.append(partialCall);
buff.append(",function() { ").append(success).append("}.bind(this)");
buff.append(",function() { ").append(failure).append("}.bind(this)");
if (precondition != null)
{
buff.append(", function() {");
buff.append(precondition);
buff.append("}.bind(this)");
}
String channel = getChannelName();
if (channel != null)
{
if (precondition == null)
{
buff.append(", null");
}
buff.append(", '");
buff.append(channel);
buff.append("'");
}
buff.append(");");
CharSequence call = buff;
if (!Strings.isEmpty(indicatorId))
{
final AppendingStringBuffer indicatorWithPrecondition = new AppendingStringBuffer(
"if (");
if (precondition != null)
{
indicatorWithPrecondition.append("function(){")
.append(precondition)
.append("}.bind(this)()");
}
else
{
indicatorWithPrecondition.append("true");
}
indicatorWithPrecondition.append(") { Wicket.showIncrementally('")
.append(indicatorId)
.append("');}")
.append(call);
call = indicatorWithPrecondition;
}
if (decorator != null)
{
call = decorator.decorateScript(getComponent(), call);
}
return call;
}
protected String getChannelName()
{
return null;
}
/**
* Finds the markup id of the indicator. The default search order is: component, behavior,
* component's parent hierarchy.
*
* @return markup id or <code>null</code> if no indicator found
*/
protected String findIndicatorId()
{
if (getComponent() instanceof IAjaxIndicatorAware)
{
return ((IAjaxIndicatorAware)getComponent()).getAjaxIndicatorMarkupId();
}
if (this instanceof IAjaxIndicatorAware)
{
return ((IAjaxIndicatorAware)this).getAjaxIndicatorMarkupId();
}
Component parent = getComponent().getParent();
while (parent != null)
{
if (parent instanceof IAjaxIndicatorAware)
{
return ((IAjaxIndicatorAware)parent).getAjaxIndicatorMarkupId();
}
parent = parent.getParent();
}
return null;
}
/**
* @see org.apache.wicket.behavior.IBehaviorListener#onRequest()
*/
public final void onRequest()
{
WebApplication app = (WebApplication)getComponent().getApplication();
AjaxRequestTarget target = app.newAjaxRequestTarget(getComponent().getPage());
RequestCycle requestCycle = RequestCycle.get();
requestCycle.scheduleRequestHandlerAfterCurrent(target);
respond(target);
}
/**
* @param target
* The AJAX target
*/
// TODO rename this to onEvent or something? respond is mostly the same as
// onRender
// this is not the case this is still the event handling period. respond is
// called
// in the RequestCycle on the AjaxRequestTarget..
protected abstract void respond(AjaxRequestTarget target);
/**
* Wraps the provided javascript with a throttled block. Throttled behaviors only execute once
* within the given delay even though they are triggered multiple times.
* <p>
* For example, this is useful when attaching an event behavior to the onkeypress event. It is
* not desirable to have an ajax call made every time the user types so we throttle that call to
* a desirable delay, such as once per second. This gives us a near real time ability to provide
* feedback without overloading the server with ajax calls.
*
* @param script
* javascript to be throttled
* @param throttleId
* the id of the throttle to be used. Usually this should remain constant for the
* same javascript block.
* @param throttleDelay
* time span within which the javascript block will only execute once
* @return wrapped javascript
*/
public static CharSequence throttleScript(CharSequence script, String throttleId,
Duration throttleDelay)
{
if (Strings.isEmpty(script))
{
throw new IllegalArgumentException("script cannot be empty");
}
if (Strings.isEmpty(throttleId))
{
throw new IllegalArgumentException("throttleId cannot be empty");
}
if (throttleDelay == null)
{
throw new IllegalArgumentException("throttleDelay cannot be null");
}
return new AppendingStringBuffer("wicketThrottler.throttle( '").append(throttleId)
.append("', ")
.append(throttleDelay.getMilliseconds())
.append(", function() { ")
.append(script)
.append("}.bind(this));");
}
}