/*

  * 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.myfaces.view.facelets.tag.jsf;

 import javax.el.MethodExpression;

 import javax.faces.component.EditableValueHolder;

 import javax.faces.component.UIComponent;

 import javax.faces.context.FacesContext;

 import javax.faces.event.MethodExpressionValueChangeListener;

 import javax.faces.event.ValueChangeEvent;

 import javax.faces.validator.MethodExpressionValidator;

 import javax.faces.view.facelets.FaceletContext;

 import javax.faces.view.facelets.MetaRule;

 import javax.faces.view.facelets.Metadata;

 import javax.faces.view.facelets.MetadataTarget;

 import javax.faces.view.facelets.TagAttribute;

 import org.apache.myfaces.view.facelets.FaceletCompositionContext;

 /**

  * 

  * @author Jacob Hookom

  * @version $Id$

  */

 public final class EditableValueHolderRule extends MetaRule

 {

     final static class LiteralValidatorMetadata extends Metadata

     {

         private final String validatorId;

         public LiteralValidatorMetadata(String validatorId)

         {

             this.validatorId = validatorId;

         }

         public void applyMetadata(FaceletContext ctx, Object instance)

         {

             ((EditableValueHolder) instance).addValidator(ctx.getFacesContext().getApplication()

                     .createValidator(this.validatorId));

         }

     }

     final static class ValueChangedExpressionMetadata extends Metadata

     {

         private final TagAttribute attr;

         public ValueChangedExpressionMetadata(TagAttribute attr)

         {

             this.attr = attr;

         }

         public void applyMetadata(FaceletContext ctx, Object instance)

         {

             // From JSF 2.0 it is possible to have valueChangeListener method without ValueChangeEvent parameter. 

             // It seems that MethodExpressionValueChangeListener from API contains support for it but there is one big

             // problem - one-arg constructor will not preserve the current VariableMapper.

             // This is a problem when using facelets and <ui:decorate/> with EL params (see MYFACES-2541 for details).

             // So we must create two MethodExpressions here - both are created from the current 

             // facelets context and thus variable mapping will work.

             final MethodExpression methodExpressionOneArg = attr.getMethodExpression(ctx, null, VALUECHANGE_SIG);

             final MethodExpression methodExpressionZeroArg = attr.getMethodExpression(ctx, null, EMPTY_CLASS_ARRAY);

             if (FaceletCompositionContext.getCurrentInstance(ctx).isUsingPSSOnThisView())

             {

                 ((EditableValueHolder) instance).addValueChangeListener(

                       new PartialMethodExpressionValueChangeListener(methodExpressionOneArg, methodExpressionZeroArg));

             }

             else

             {

                 ((EditableValueHolder) instance).addValueChangeListener(

                         new MethodExpressionValueChangeListener(methodExpressionOneArg, methodExpressionZeroArg));

             }

         }

     }

     final static class ValidatorExpressionMetadata extends Metadata

     {

         private final TagAttribute attr;

         public ValidatorExpressionMetadata(TagAttribute attr)

         {

             this.attr = attr;

         }

         public void applyMetadata(FaceletContext ctx, Object instance)

         {

             if (FaceletCompositionContext.getCurrentInstance(ctx).isUsingPSSOnThisView())

             {

                 ((EditableValueHolder) instance).addValidator(new PartialMethodExpressionValidator(this.attr

                         .getMethodExpression(ctx, null, VALIDATOR_SIG)));

             }

             else

             {

                 ((EditableValueHolder) instance).addValidator(new MethodExpressionValidator(this.attr

                         .getMethodExpression(ctx, null, VALIDATOR_SIG)));

             }

         }

     }

     private final static Class<?>[] VALIDATOR_SIG = new Class[] { FacesContext.class, UIComponent.class, Object.class };

     private final static Class<?>[] VALUECHANGE_SIG = new Class[] { ValueChangeEvent.class };

     private final static Class<?>[] EMPTY_CLASS_ARRAY = new Class[0];

     public final static EditableValueHolderRule INSTANCE = new EditableValueHolderRule();

     public Metadata applyRule(String name, TagAttribute attribute, MetadataTarget meta)

     {

         if (meta.isTargetInstanceOf(EditableValueHolder.class))

         {

             if ("validator".equals(name))

             {

                 if (attribute.isLiteral())

                 {

                     return new LiteralValidatorMetadata(attribute.getValue());

                 }

                 else

                 {

                     return new ValidatorExpressionMetadata(attribute);

                 }

             }

             if ("valueChangeListener".equals(name))

             {

                 return new ValueChangedExpressionMetadata(attribute);

             }

         }

         return null;

     }

 }