// Copyright 2008 Thiago H. de Paula Figueiredo

 //

 // Licensed 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 br.com.arsmachina.tapestrycrud.components;

 import org.apache.tapestry5.BindingConstants;

 import org.apache.tapestry5.ComponentResources;

 import org.apache.tapestry5.Field;

 import org.apache.tapestry5.MarkupWriter;

 import org.apache.tapestry5.ValidationDecorator;

 import org.apache.tapestry5.annotations.AfterRender;

 import org.apache.tapestry5.annotations.BeginRender;

 import org.apache.tapestry5.annotations.Environmental;

 import org.apache.tapestry5.annotations.IncludeStylesheet;

 import org.apache.tapestry5.annotations.Mixin;

 import org.apache.tapestry5.annotations.Parameter;

 import org.apache.tapestry5.annotations.SupportsInformalParameters;

 import org.apache.tapestry5.corelib.components.Label;

 import org.apache.tapestry5.corelib.mixins.DiscardBody;

 import org.apache.tapestry5.dom.Element;

 import org.apache.tapestry5.ioc.annotations.Inject;

 import org.apache.tapestry5.services.Heartbeat;

 import br.com.arsmachina.tapestrycrud.Constants;

 /**

  * <p>

  * {@link Label} subclass that always ignores its body and generates the label name from the

  * corresponding field id.

  * </p>

  * <p>

  * This class' code was initially copied from {@link Label}, as one of its methods (<code>afterRender</code>)

  * has package visibility and thus cannot be overriden.

  * </p>

  * 

  * @author Thiago H. de Paula Figueiredo

  */

 @SupportsInformalParameters

 @IncludeStylesheet(Constants.TAPESTRY_CRUD_CSS_ASSET)

 public class ImprovedLabel {

         /**

          * Discards the body of this class.

          */

         @SuppressWarnings("unused")

         @Mixin

         private DiscardBody discardBody;

         /**

          * The for parameter is used to identify the {@link Field} linked to this label (it is named

          * this way because it results in the for attribute of the label element).

          */

         @Parameter(name = "for", required = true, defaultPrefix = BindingConstants.COMPONENT)

         private Field field;

         @Environmental

         private Heartbeat heartbeat;

         @Environmental

         private ValidationDecorator decorator;

         @Inject

         private ComponentResources resources;

         private Element labelElement;

         @BeginRender

         void begin(MarkupWriter writer) {

                 final Field field = this.field;

                 decorator.beforeLabel(field);

                 labelElement = writer.element("label");

                 resources.renderInformalParameters(writer);

                 // Since we don't know if the field has rendered yet, we need to defer writing the for and

                 // id

                 // attributes until we know the field has rendered (and set its clientId property). That's

                 // exactly what Heartbeat is for.

                 Runnable command = new Runnable() {

                         public void run() {

                                 String fieldId = field.getClientId();

                                 labelElement.forceAttributes("for", fieldId, "id", fieldId + ":label");

                                 decorator.insideLabel(field, labelElement);

                         }

                 };

                 heartbeat.defer(command);

         }

         @AfterRender

         void after(MarkupWriter writer) {

                 // If the Label element has a body that renders some non-blank output, that takes

                 // precendence

                 // over the label string provided by the field.

                 // removed code from label. the rest was not modified.

                 // boolean bodyIsBlank = InternalUtils.isBlank(labelElement.getChildMarkup());

                 //

                 // if (bodyIsBlank)

                 // writer.write(field.getLabel());

                 writer.write(field.getLabel());

                 writer.end(); // label

                 decorator.afterLabel(field);

         }

 }