package net.sf.tacos.components;

 import java.util.HashMap;

 import java.util.Map;

 import org.apache.tapestry.AbstractComponent;

 import org.apache.tapestry.IActionListener;

 import org.apache.tapestry.IDirect;

 import org.apache.tapestry.IMarkupWriter;

 import org.apache.tapestry.IRequestCycle;

 import org.apache.tapestry.IScript;

 import org.apache.tapestry.Tapestry;

 import org.apache.tapestry.TapestryUtils;

 import org.apache.tapestry.engine.DirectServiceParameter;

 import org.apache.tapestry.engine.IEngineService;

 import org.apache.tapestry.engine.ILink;

 import org.apache.tapestry.listener.ListenerInvoker;

 /**

  * A component for creating a javascript function whose body

  * is a call of an url definied by the direct service. This component is similar to

  * <a href="http://tapestry.apache.org/tapestry4.1/components/link/directlink.html">DirectLink</a>

  * component but allows you to call listener methods from javascript code without to click on any link or button.

  * <p>The required parameters are: a listener method and the name of the function to generate.</p>

  * <pre>

  *<span jwcid="@tacos:ClientLink" listener="listener:onClick" function="myFunction"/>

  *</pre>

  *<p>The generated function can be used like this:</p>

  *<pre>

  *function test(){

  *        ...

  *        myFunction();

  *}

  *</pre>

  * 

  * @author Igor Drobiazko

  *

  */

 public abstract class ClientLink extends AbstractComponent implements IDirect{

         /**

          * {@inheritDoc}

          */

         protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle) {                

         renderBody(writer, cycle);

         if (!cycle.isRewinding()) {

             Map params = new HashMap();

             params.put("url", getLink().getURL());        

             params.put("function", getFunction());

             getScript().execute(this, cycle, TapestryUtils.getPageRenderSupport(cycle, this), params);

         }

         }

         /**

          * {@inheritDoc}

          */

         public void trigger(IRequestCycle cycle) {

         IActionListener listener = getListener();

         if (listener == null)

             throw Tapestry.createRequiredParameterException(this, "listener");

         getListenerInvoker().invokeListener(listener, this, cycle);

         }

         /**Returns a link*/

         private ILink getLink(){

                 DirectServiceParameter dsp = new DirectServiceParameter(this);

                 return getEngine().getLink(isStateful(), dsp);

         }

     /** The required listener parameter. */

     public abstract IActionListener getListener();

     /** Name of the javascript function to generate. */

     public abstract String getFunction();

     /** Injected script. */

     public abstract IScript getScript();

     /** Injected listener invoker. */

     public abstract ListenerInvoker getListenerInvoker();

     /** Injected engine service . */

     public abstract IEngineService getEngine();

 }