001// Copyright 2007, 2008 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007//     http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.internal.structure;
016
017import org.apache.tapestry5.Block;
018import org.apache.tapestry5.MarkupWriter;
019import org.apache.tapestry5.ioc.BaseLocatable;
020import org.apache.tapestry5.ioc.Location;
021import org.apache.tapestry5.ioc.internal.util.CollectionFactory;
022import org.apache.tapestry5.runtime.RenderCommand;
023import org.apache.tapestry5.runtime.RenderQueue;
024
025import java.util.List;
026
027public class BlockImpl extends BaseLocatable implements Block, BodyPageElement, RenderCommand
028{
029    // We could lazily create this, but for (parameter) block elements the case
030    // for an empty block is extremely rare.
031
032    private final List<RenderCommand> elements = CollectionFactory.newList();
033
034    private final String description;
035
036    public BlockImpl(Location location, String description)
037    {
038        super(location);
039
040        this.description = description;
041    }
042
043    public void addToBody(RenderCommand element)
044    {
045        elements.add(element);
046    }
047
048    /**
049     * Pushes all the elements of the body of this block onto the queue in appropriate order.
050     */
051    public void render(MarkupWriter writer, RenderQueue queue)
052    {
053        int count = elements.size();
054        for (int i = count - 1; i >= 0; i--)
055            queue.push(elements.get(i));
056    }
057
058    @Override
059    public String toString()
060    {
061        return String.format("Block[%s, at %s]", description, getLocation());
062    }
063}