THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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It often occurs that multiple wicket behaviors must be used to obtain a certain effect. An example can be a tooltip that requires both a javascript header contribution and an attribute modifier. Another example is that of a confirmation popup when someone clicks on an certain button. Using a composite behavior, which is an example of the composite design pattern, it is posisble possible to realize things like this by adding just a single composite behavior object to a component (e.g. ToolTipBehavior, ConfirmationBehavior) instead of having to add multiple behaviors just to obtain one effect in the user interface. This enhances readability and maintainability of the code.
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Composite behavior, first attempt
A solution is to use the composite design pattern and create a composite behavior is fairly easy to implement. .
This can be done as follows:
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import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import wicket.Component;
import wicket.Response;
import wicket.behavior.IBehavior;
import wicket.markup.ComponentTag;
import wicket.markup.html.IHeaderContributor;
/**
* Represents a composite behavior allowing the user to attach multiple behaviors to a
* component at once.
*
*/
public class CompositeBehavior implements IBehavior, IHeaderContributor {
private List<IBehavior> _behaviors;
public CompositeBehavior(IBehavior[] aBehaviors) {
_behaviors = new ArrayList<IBehavior>(Arrays.asList(aBehaviors));
}
public void add(IBehavior aBehavior) {
_behaviors.add(aBehavior);
}
public void bind(Component aComponent) {
for (IBehavior behavior: _behaviors) {
behavior.bind(aComponent);
}
}
public void detachModel(Component aComponent) {
for (IBehavior behavior: _behaviors) {
behavior.detachModel(aComponent);
}
}
public void exception(Component aComponent, RuntimeException aException) {
for (IBehavior behavior: _behaviors) {
behavior.exception(aComponent, aException);
}
}
public void onComponentTag(Component aComponent, ComponentTag aTag) {
for (IBehavior behavior: _behaviors) {
behavior.onComponentTag(aComponent, aTag);
}
}
public void rendered(Component aComponent) {
for (IBehavior behavior: _behaviors) {
behavior.rendered(aComponent);
}
}
public void renderHead(Response aResponse) {
for (IBehavior behavior: _behaviors) {
if ( behavior instanceof IHeaderContributor) {
((IHeaderContributor)behavior).renderHead(aResponse);
}
}
}
}
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