    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.commons.Location;
    020import org.apache.tapestry5.commons.util.CollectionFactory;
    021import org.apache.tapestry5.ioc.BaseLocatable;
    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}