// Copyright 2009 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.pageload;

 import org.apache.tapestry5.internal.parser.TemplateToken;

 import org.apache.tapestry5.internal.parser.TokenType;

 import org.apache.tapestry5.ioc.internal.util.CollectionFactory;

 import org.apache.tapestry5.runtime.RenderCommand;

 import java.util.List;

 /**

  * Used when constructing a {@link org.apache.tapestry5.internal.pageload.AssemblerContext}, encapsulating the

  * assembler, the {@link org.apache.tapestry5.internal.pageload.TokenStream} for the component's template, and helping

  * to consolidate composable render commands (that is, a series of render commands that are not components can be

  * replaced with a single {@link org.apache.tapestry5.internal.pageload.CompositeRenderCommand} which reduces the number

  * of render operations for the page).

  */

 class AssemblerContext implements TokenStream

 {

     final ComponentAssembler assembler;

     final TokenStream stream;

     private final List<RenderCommand> composable = CollectionFactory.newList();

     AssemblerContext(ComponentAssembler assembler, TokenStream stream)

     {

         this.assembler = assembler;

         this.stream = stream;

     }

     public boolean more()

     {

         return stream.more();

     }

     public TemplateToken next()

     {

         return stream.next();

     }

     public <T extends TemplateToken> T next(Class<T> type)

     {

         return stream.next(type);

     }

     public TokenType peekType()

     {

         return stream.peekType();

     }

     void addComposable(RenderCommand command)

     {

         composable.add(command);

     }

     void flushComposable()

     {

         switch (composable.size())

         {

             case 0:

                 return;

             case 1:

                 addRenderCommand(composable.get(0));

                 break;

             default:

                 addRenderCommand(new CompositeRenderCommand(composable.toArray(new RenderCommand[composable.size()])));

                 break;

         }

         composable.clear();

     }

     void add(PageAssemblyAction action)

     {

         flushComposable();

         assembler.add(action);

     }

     private void addRenderCommand(final RenderCommand command)

     {

         assembler.add(new PageAssemblyAction()

         {

             public void execute(PageAssembly pageAssembly)

             {

                 pageAssembly.addRenderCommand(command);

             }

         });

     }

 }