// Copyright 2006, 2007 The Apache Software Foundation

 //

 // 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 org.apache.tapestry5.internal.parser;

 import org.apache.tapestry5.ioc.Location;

 /**

  * The start element of a component within the template. Will be followed by a series of {@link

  * org.apache.tapestry5.internal.parser.AttributeToken}s for any attributes (outside of id and type), and eventually

  * will be balanced by an {@link org.apache.tapestry5.internal.parser.EndElementToken}.

  */

 public class StartComponentToken extends TemplateToken

 {

     private final String elementName;

     private final String id;

     private final String componentType;

     private final String mixins;

     /**

      * @param elementName the name of the element from which this component was parsed, or null if the element was the

      *                    t:comp placeholder

      * @param id          the id of the component (may be null for anonymous components)

      * @param type        the type of component (may be null if the component type is specified outside the template)

      * @param mixins      a comma-separated list of mixins (possibly null)

      * @param location    the location within the template at which the element was parsed

      */

     public StartComponentToken(String elementName, String id, String type, String mixins,

                                Location location)

     {

         super(TokenType.START_COMPONENT, location);

         // TODO: id or type may be null, but not both!

         this.elementName = elementName;

         this.id = id;

         componentType = type;

         this.mixins = mixins;

     }

     /**

      * Returns the element for this component. When using the <t:comp> placeholder, this value will be null. When

      * using "invisible instrumentation", where t:id or t:type attributes are added to existing elements, this is the

      * local name of the element so attached.

      *

      * @return the element name or null

      */

     public String getElementName()

     {

         return elementName;

     }

     /**

      * Returns a non-blank id if one was provided in the template. If the id attribute was missing (or the value was

      * blank), returns null.

      */

     public String getId()

     {

         return id;

     }

     /**

      * Returns a non-blank component type if one was provided in the template. If the type attribute was missing (or the

      * value was blank), returns null.

      */

     public String getComponentType()

     {

         return componentType;

     }

     @Override

     public String toString()

     {

         StringBuilder builder = new StringBuilder();

         add(builder, "element", elementName);

         add(builder, "id", id);

         add(builder, "type", componentType);

         add(builder, "mixins", mixins);

         builder.insert(0, "StartComponentToken[");

         builder.append("]");

         return builder.toString();

     }

     private void add(StringBuilder builder, String label, String value)

     {

         if (value == null)

             return;

         if (builder.length() > 0)

             builder.append(" ");

         builder.append(label);

         builder.append("=");

         builder.append(value);

     }

     /**

      * Returns the list of mixins for this component instance, or null for no mixins.

      */

     public String getMixins()

     {

         return mixins;

     }

 }