/*
* 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.examples.compref;
import org.apache.wicket.AttributeModifier;
import org.apache.wicket.examples.WicketExamplePage;
import org.apache.wicket.markup.html.basic.Label;
import org.apache.wicket.markup.html.link.Link;
import org.apache.wicket.model.Model;
import org.apache.wicket.model.PropertyModel;
/**
* Page with examples on {@link org.apache.wicket.markup.html.link.Link}.
*
* @author Eelco Hillenius
*/
public class LinkPage extends WicketExamplePage
{
/**
* Constructor
*/
public LinkPage()
{
// power to the annonymous classes!
// first create a simple value holder object
final Count count1 = new Count();
// add a link which, when clicked, increases our counter when a link is clicked, its onClick
// method is called
Link link1 = new Link("link1")
{
@Override
public void onClick()
{
count1.increment();
}
};
add(link1);
// add a counter label to the link so that we can display it in the body of the link
link1.add(new Label("label1", new Model<String>()
{
@Override
public String getObject()
{
return count1.toString();
}
}));
final Count count2 = new Count();
// Same idea as above, but now we record a state change. Note that the URL will change
// because of this, and pressing the back button and clicking the link again would revert to
// the older value. The same thing could have been achieved by using setModelObject,
// which implicitly registers a state change (of type ComponentModelChange).
Link linkWithStateChange = new Link("linkWithStateChange")
{
@Override
public void onClick()
{
count2.increment();
addStateChange();
}
};
add(linkWithStateChange);
linkWithStateChange.add(new Label("label", new PropertyModel<>(count2, "count")));
// we can attach Link components to any HTML tag we want. If it is an anchor (<a href...),
// the url to this component is put in the href attribute. For other components, a onclick
// javascript event handler is created that triggers the round trip
// it is of course possible to - instead of the above approach - hide as much of the
// component as possible within a class.
class CustomLink extends Link
{
final Count count2;
/**
* Construct.
*
* @param id
*/
public CustomLink(String id)
{
super(id);
count2 = new Count();
add(new ClickCountLabel("label2", count2));
}
@Override
public void onClick()
{
count2.increment();
}
}
add(new CustomLink("link2"));
// and if we know we are going to attach it to a <input type="button> tag, we shouldn't use
// a label, but an AttributeModifier instead.
class ButtonLink extends Link
{
final Count count3;
/**
* Construct.
*
* @param id
*/
public ButtonLink(String id)
{
super(id);
count3 = new Count();
add(new AttributeModifier("value", new Model<String>()
{
@Override
public String getObject()
{
// we just replace the whole string. You could use custom AttributeModifiers
// to e.g. just replace one part of the string if you want
return "this button is clicked " + count3.getCount() + " times";
}
}));
}
@Override
public void onClick()
{
count3.increment();
}
}
add(new ButtonLink("link3"));
}
/**
* Simple custom label that displays the link click count.
*/
private static class ClickCountLabel extends Label
{
/**
* Construct.
*
* @param id
* component id
* @param clickCount
* the count object
*/
public ClickCountLabel(String id, final Count clickCount)
{
// call super with a simple annonymous class model that displays the
// current number of clicks
super(id, new Model<String>()
{
@Override
public String getObject()
{
return clickCount.toString();
}
});
}
}
// ----------
final Count count1 = new Count(); // simple counter object
Link link1 = new Link("link1")
{
@Override
public void onClick()
{
count1.increment();
}
};
/**
* Override base method to provide an explanation
*/
@Override
protected void explain()
{
String html = "<a href=\"#\" wicket:id=\"link1\">this link is clicked <span wicket:id=\"label1\">n</span> times</a>";
String code = " final Count count1 = new Count(); // simple counter object\n"
+ " Link link1 = new Link(\"link1\") {\n"
+ " public void onClick() {\n"
+ " count1.increment();\n"
+ " }\n"
+ " };\n"
+ " link1.add(new Label(\"label1\", new Model<String>() {\n"
+ " public Object getObject() {\n"
+ " return count1.toString();\n"
+ " }\n"
+ " }));\n"
+ " add(link1);";
add(new ExplainPanel(html, code));
}
}