001// Copyright 2004, 2005 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.tapestry.wml;
016
017import org.apache.hivemind.HiveMind;
018import org.apache.tapestry.AbstractComponent;
019import org.apache.tapestry.IMarkupWriter;
020import org.apache.tapestry.IRequestCycle;
021
022/**
023 * The do element provides a general mechanism for the user to act upon the current card, in other
024 * words a card-level user interface element. The representation of the do element is user agent
025 * dependent and the author must only assume that the element is mapped to a unique user interface
026 * widget that the user can activate. For example, the widget mapping may be to a graphically
027 * rendered button, a soft or function key, a voice-activated command sequence, or any other
028 * interface that has a simple "activate" operation with no inter-operation persistent state. The do
029 * element may appear at both the card and deck-level.
030 * 
031 * @author David Solis
032 * @since 3.0
033 */
034
035public abstract class Do extends AbstractComponent
036{
037    /**
038     * @see AbstractComponent#renderComponent(IMarkupWriter, IRequestCycle)
039     */
040
041    protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
042    {
043        boolean render = !cycle.isRewinding();
044
045        if (render)
046        {
047            writer.begin("do");
048
049            writer.attribute("type", getType());
050
051            String label = getLabel();
052            if (HiveMind.isNonBlank(label))
053                writer.attribute("label", label);
054
055            renderInformalParameters(writer, cycle);
056        }
057
058        renderBody(writer, cycle);
059
060        if (render)
061            writer.end();
062    }
063
064    public abstract String getType();
065
066    public abstract String getLabel();
067}